[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/drivers/block/xen-blkback/Makefile b/src/kernel/linux/v4.14/drivers/block/xen-blkback/Makefile
new file mode 100644
index 0000000..e491c1b
--- /dev/null
+++ b/src/kernel/linux/v4.14/drivers/block/xen-blkback/Makefile
@@ -0,0 +1,3 @@
+obj-$(CONFIG_XEN_BLKDEV_BACKEND) := xen-blkback.o
+
+xen-blkback-y := blkback.o xenbus.o
diff --git a/src/kernel/linux/v4.14/drivers/block/xen-blkback/blkback.c b/src/kernel/linux/v4.14/drivers/block/xen-blkback/blkback.c
new file mode 100644
index 0000000..c1d1b94
--- /dev/null
+++ b/src/kernel/linux/v4.14/drivers/block/xen-blkback/blkback.c
@@ -0,0 +1,1503 @@
+/******************************************************************************
+ *
+ * Back-end of the driver for virtual block devices. This portion of the
+ * driver exports a 'unified' block-device interface that can be accessed
+ * by any operating system that implements a compatible front end. A
+ * reference front-end implementation can be found in:
+ * drivers/block/xen-blkfront.c
+ *
+ * Copyright (c) 2003-2004, Keir Fraser & Steve Hand
+ * Copyright (c) 2005, Christopher Clark
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#define pr_fmt(fmt) "xen-blkback: " fmt
+
+#include <linux/spinlock.h>
+#include <linux/kthread.h>
+#include <linux/list.h>
+#include <linux/delay.h>
+#include <linux/freezer.h>
+#include <linux/bitmap.h>
+
+#include <xen/events.h>
+#include <xen/page.h>
+#include <xen/xen.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/hypercall.h>
+#include <xen/balloon.h>
+#include <xen/grant_table.h>
+#include "common.h"
+
+/*
+ * Maximum number of unused free pages to keep in the internal buffer.
+ * Setting this to a value too low will reduce memory used in each backend,
+ * but can have a performance penalty.
+ *
+ * A sane value is xen_blkif_reqs * BLKIF_MAX_SEGMENTS_PER_REQUEST, but can
+ * be set to a lower value that might degrade performance on some intensive
+ * IO workloads.
+ */
+
+static int xen_blkif_max_buffer_pages = 1024;
+module_param_named(max_buffer_pages, xen_blkif_max_buffer_pages, int, 0644);
+MODULE_PARM_DESC(max_buffer_pages,
+"Maximum number of free pages to keep in each block backend buffer");
+
+/*
+ * Maximum number of grants to map persistently in blkback. For maximum
+ * performance this should be the total numbers of grants that can be used
+ * to fill the ring, but since this might become too high, specially with
+ * the use of indirect descriptors, we set it to a value that provides good
+ * performance without using too much memory.
+ *
+ * When the list of persistent grants is full we clean it up using a LRU
+ * algorithm.
+ */
+
+static int xen_blkif_max_pgrants = 1056;
+module_param_named(max_persistent_grants, xen_blkif_max_pgrants, int, 0644);
+MODULE_PARM_DESC(max_persistent_grants,
+ "Maximum number of grants to map persistently");
+
+/*
+ * Maximum number of rings/queues blkback supports, allow as many queues as there
+ * are CPUs if user has not specified a value.
+ */
+unsigned int xenblk_max_queues;
+module_param_named(max_queues, xenblk_max_queues, uint, 0644);
+MODULE_PARM_DESC(max_queues,
+ "Maximum number of hardware queues per virtual disk." \
+ "By default it is the number of online CPUs.");
+
+/*
+ * Maximum order of pages to be used for the shared ring between front and
+ * backend, 4KB page granularity is used.
+ */
+unsigned int xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
+module_param_named(max_ring_page_order, xen_blkif_max_ring_order, int, S_IRUGO);
+MODULE_PARM_DESC(max_ring_page_order, "Maximum order of pages to be used for the shared ring");
+/*
+ * The LRU mechanism to clean the lists of persistent grants needs to
+ * be executed periodically. The time interval between consecutive executions
+ * of the purge mechanism is set in ms.
+ */
+#define LRU_INTERVAL 100
+
+/*
+ * When the persistent grants list is full we will remove unused grants
+ * from the list. The percent number of grants to be removed at each LRU
+ * execution.
+ */
+#define LRU_PERCENT_CLEAN 5
+
+/* Run-time switchable: /sys/module/blkback/parameters/ */
+static unsigned int log_stats;
+module_param(log_stats, int, 0644);
+
+#define BLKBACK_INVALID_HANDLE (~0)
+
+/* Number of free pages to remove on each call to gnttab_free_pages */
+#define NUM_BATCH_FREE_PAGES 10
+
+static inline int get_free_page(struct xen_blkif_ring *ring, struct page **page)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ring->free_pages_lock, flags);
+ if (list_empty(&ring->free_pages)) {
+ BUG_ON(ring->free_pages_num != 0);
+ spin_unlock_irqrestore(&ring->free_pages_lock, flags);
+ return gnttab_alloc_pages(1, page);
+ }
+ BUG_ON(ring->free_pages_num == 0);
+ page[0] = list_first_entry(&ring->free_pages, struct page, lru);
+ list_del(&page[0]->lru);
+ ring->free_pages_num--;
+ spin_unlock_irqrestore(&ring->free_pages_lock, flags);
+
+ return 0;
+}
+
+static inline void put_free_pages(struct xen_blkif_ring *ring, struct page **page,
+ int num)
+{
+ unsigned long flags;
+ int i;
+
+ spin_lock_irqsave(&ring->free_pages_lock, flags);
+ for (i = 0; i < num; i++)
+ list_add(&page[i]->lru, &ring->free_pages);
+ ring->free_pages_num += num;
+ spin_unlock_irqrestore(&ring->free_pages_lock, flags);
+}
+
+static inline void shrink_free_pagepool(struct xen_blkif_ring *ring, int num)
+{
+ /* Remove requested pages in batches of NUM_BATCH_FREE_PAGES */
+ struct page *page[NUM_BATCH_FREE_PAGES];
+ unsigned int num_pages = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ring->free_pages_lock, flags);
+ while (ring->free_pages_num > num) {
+ BUG_ON(list_empty(&ring->free_pages));
+ page[num_pages] = list_first_entry(&ring->free_pages,
+ struct page, lru);
+ list_del(&page[num_pages]->lru);
+ ring->free_pages_num--;
+ if (++num_pages == NUM_BATCH_FREE_PAGES) {
+ spin_unlock_irqrestore(&ring->free_pages_lock, flags);
+ gnttab_free_pages(num_pages, page);
+ spin_lock_irqsave(&ring->free_pages_lock, flags);
+ num_pages = 0;
+ }
+ }
+ spin_unlock_irqrestore(&ring->free_pages_lock, flags);
+ if (num_pages != 0)
+ gnttab_free_pages(num_pages, page);
+}
+
+#define vaddr(page) ((unsigned long)pfn_to_kaddr(page_to_pfn(page)))
+
+static int do_block_io_op(struct xen_blkif_ring *ring);
+static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
+ struct blkif_request *req,
+ struct pending_req *pending_req);
+static void make_response(struct xen_blkif_ring *ring, u64 id,
+ unsigned short op, int st);
+
+#define foreach_grant_safe(pos, n, rbtree, node) \
+ for ((pos) = container_of(rb_first((rbtree)), typeof(*(pos)), node), \
+ (n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL; \
+ &(pos)->node != NULL; \
+ (pos) = container_of(n, typeof(*(pos)), node), \
+ (n) = (&(pos)->node != NULL) ? rb_next(&(pos)->node) : NULL)
+
+
+/*
+ * We don't need locking around the persistent grant helpers
+ * because blkback uses a single-thread for each backend, so we
+ * can be sure that this functions will never be called recursively.
+ *
+ * The only exception to that is put_persistent_grant, that can be called
+ * from interrupt context (by xen_blkbk_unmap), so we have to use atomic
+ * bit operations to modify the flags of a persistent grant and to count
+ * the number of used grants.
+ */
+static int add_persistent_gnt(struct xen_blkif_ring *ring,
+ struct persistent_gnt *persistent_gnt)
+{
+ struct rb_node **new = NULL, *parent = NULL;
+ struct persistent_gnt *this;
+ struct xen_blkif *blkif = ring->blkif;
+
+ if (ring->persistent_gnt_c >= xen_blkif_max_pgrants) {
+ if (!blkif->vbd.overflow_max_grants)
+ blkif->vbd.overflow_max_grants = 1;
+ return -EBUSY;
+ }
+ /* Figure out where to put new node */
+ new = &ring->persistent_gnts.rb_node;
+ while (*new) {
+ this = container_of(*new, struct persistent_gnt, node);
+
+ parent = *new;
+ if (persistent_gnt->gnt < this->gnt)
+ new = &((*new)->rb_left);
+ else if (persistent_gnt->gnt > this->gnt)
+ new = &((*new)->rb_right);
+ else {
+ pr_alert_ratelimited("trying to add a gref that's already in the tree\n");
+ return -EINVAL;
+ }
+ }
+
+ bitmap_zero(persistent_gnt->flags, PERSISTENT_GNT_FLAGS_SIZE);
+ set_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags);
+ /* Add new node and rebalance tree. */
+ rb_link_node(&(persistent_gnt->node), parent, new);
+ rb_insert_color(&(persistent_gnt->node), &ring->persistent_gnts);
+ ring->persistent_gnt_c++;
+ atomic_inc(&ring->persistent_gnt_in_use);
+ return 0;
+}
+
+static struct persistent_gnt *get_persistent_gnt(struct xen_blkif_ring *ring,
+ grant_ref_t gref)
+{
+ struct persistent_gnt *data;
+ struct rb_node *node = NULL;
+
+ node = ring->persistent_gnts.rb_node;
+ while (node) {
+ data = container_of(node, struct persistent_gnt, node);
+
+ if (gref < data->gnt)
+ node = node->rb_left;
+ else if (gref > data->gnt)
+ node = node->rb_right;
+ else {
+ if(test_bit(PERSISTENT_GNT_ACTIVE, data->flags)) {
+ pr_alert_ratelimited("requesting a grant already in use\n");
+ return NULL;
+ }
+ set_bit(PERSISTENT_GNT_ACTIVE, data->flags);
+ atomic_inc(&ring->persistent_gnt_in_use);
+ return data;
+ }
+ }
+ return NULL;
+}
+
+static void put_persistent_gnt(struct xen_blkif_ring *ring,
+ struct persistent_gnt *persistent_gnt)
+{
+ if(!test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags))
+ pr_alert_ratelimited("freeing a grant already unused\n");
+ set_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags);
+ clear_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags);
+ atomic_dec(&ring->persistent_gnt_in_use);
+}
+
+static void free_persistent_gnts(struct xen_blkif_ring *ring, struct rb_root *root,
+ unsigned int num)
+{
+ struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct persistent_gnt *persistent_gnt;
+ struct rb_node *n;
+ int segs_to_unmap = 0;
+ struct gntab_unmap_queue_data unmap_data;
+
+ unmap_data.pages = pages;
+ unmap_data.unmap_ops = unmap;
+ unmap_data.kunmap_ops = NULL;
+
+ foreach_grant_safe(persistent_gnt, n, root, node) {
+ BUG_ON(persistent_gnt->handle ==
+ BLKBACK_INVALID_HANDLE);
+ gnttab_set_unmap_op(&unmap[segs_to_unmap],
+ (unsigned long) pfn_to_kaddr(page_to_pfn(
+ persistent_gnt->page)),
+ GNTMAP_host_map,
+ persistent_gnt->handle);
+
+ pages[segs_to_unmap] = persistent_gnt->page;
+
+ if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST ||
+ !rb_next(&persistent_gnt->node)) {
+
+ unmap_data.count = segs_to_unmap;
+ BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
+
+ put_free_pages(ring, pages, segs_to_unmap);
+ segs_to_unmap = 0;
+ }
+
+ rb_erase(&persistent_gnt->node, root);
+ kfree(persistent_gnt);
+ num--;
+ }
+ BUG_ON(num != 0);
+}
+
+void xen_blkbk_unmap_purged_grants(struct work_struct *work)
+{
+ struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct persistent_gnt *persistent_gnt;
+ int segs_to_unmap = 0;
+ struct xen_blkif_ring *ring = container_of(work, typeof(*ring), persistent_purge_work);
+ struct gntab_unmap_queue_data unmap_data;
+
+ unmap_data.pages = pages;
+ unmap_data.unmap_ops = unmap;
+ unmap_data.kunmap_ops = NULL;
+
+ while(!list_empty(&ring->persistent_purge_list)) {
+ persistent_gnt = list_first_entry(&ring->persistent_purge_list,
+ struct persistent_gnt,
+ remove_node);
+ list_del(&persistent_gnt->remove_node);
+
+ gnttab_set_unmap_op(&unmap[segs_to_unmap],
+ vaddr(persistent_gnt->page),
+ GNTMAP_host_map,
+ persistent_gnt->handle);
+
+ pages[segs_to_unmap] = persistent_gnt->page;
+
+ if (++segs_to_unmap == BLKIF_MAX_SEGMENTS_PER_REQUEST) {
+ unmap_data.count = segs_to_unmap;
+ BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
+ put_free_pages(ring, pages, segs_to_unmap);
+ segs_to_unmap = 0;
+ }
+ kfree(persistent_gnt);
+ }
+ if (segs_to_unmap > 0) {
+ unmap_data.count = segs_to_unmap;
+ BUG_ON(gnttab_unmap_refs_sync(&unmap_data));
+ put_free_pages(ring, pages, segs_to_unmap);
+ }
+}
+
+static void purge_persistent_gnt(struct xen_blkif_ring *ring)
+{
+ struct persistent_gnt *persistent_gnt;
+ struct rb_node *n;
+ unsigned int num_clean, total;
+ bool scan_used = false, clean_used = false;
+ struct rb_root *root;
+
+ if (ring->persistent_gnt_c < xen_blkif_max_pgrants ||
+ (ring->persistent_gnt_c == xen_blkif_max_pgrants &&
+ !ring->blkif->vbd.overflow_max_grants)) {
+ goto out;
+ }
+
+ if (work_busy(&ring->persistent_purge_work)) {
+ pr_alert_ratelimited("Scheduled work from previous purge is still busy, cannot purge list\n");
+ goto out;
+ }
+
+ num_clean = (xen_blkif_max_pgrants / 100) * LRU_PERCENT_CLEAN;
+ num_clean = ring->persistent_gnt_c - xen_blkif_max_pgrants + num_clean;
+ num_clean = min(ring->persistent_gnt_c, num_clean);
+ if ((num_clean == 0) ||
+ (num_clean > (ring->persistent_gnt_c - atomic_read(&ring->persistent_gnt_in_use))))
+ goto out;
+
+ /*
+ * At this point, we can assure that there will be no calls
+ * to get_persistent_grant (because we are executing this code from
+ * xen_blkif_schedule), there can only be calls to put_persistent_gnt,
+ * which means that the number of currently used grants will go down,
+ * but never up, so we will always be able to remove the requested
+ * number of grants.
+ */
+
+ total = num_clean;
+
+ pr_debug("Going to purge %u persistent grants\n", num_clean);
+
+ BUG_ON(!list_empty(&ring->persistent_purge_list));
+ root = &ring->persistent_gnts;
+purge_list:
+ foreach_grant_safe(persistent_gnt, n, root, node) {
+ BUG_ON(persistent_gnt->handle ==
+ BLKBACK_INVALID_HANDLE);
+
+ if (clean_used) {
+ clear_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags);
+ continue;
+ }
+
+ if (test_bit(PERSISTENT_GNT_ACTIVE, persistent_gnt->flags))
+ continue;
+ if (!scan_used &&
+ (test_bit(PERSISTENT_GNT_WAS_ACTIVE, persistent_gnt->flags)))
+ continue;
+
+ rb_erase(&persistent_gnt->node, root);
+ list_add(&persistent_gnt->remove_node,
+ &ring->persistent_purge_list);
+ if (--num_clean == 0)
+ goto finished;
+ }
+ /*
+ * If we get here it means we also need to start cleaning
+ * grants that were used since last purge in order to cope
+ * with the requested num
+ */
+ if (!scan_used && !clean_used) {
+ pr_debug("Still missing %u purged frames\n", num_clean);
+ scan_used = true;
+ goto purge_list;
+ }
+finished:
+ if (!clean_used) {
+ pr_debug("Finished scanning for grants to clean, removing used flag\n");
+ clean_used = true;
+ goto purge_list;
+ }
+
+ ring->persistent_gnt_c -= (total - num_clean);
+ ring->blkif->vbd.overflow_max_grants = 0;
+
+ /* We can defer this work */
+ schedule_work(&ring->persistent_purge_work);
+ pr_debug("Purged %u/%u\n", (total - num_clean), total);
+
+out:
+ return;
+}
+
+/*
+ * Retrieve from the 'pending_reqs' a free pending_req structure to be used.
+ */
+static struct pending_req *alloc_req(struct xen_blkif_ring *ring)
+{
+ struct pending_req *req = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&ring->pending_free_lock, flags);
+ if (!list_empty(&ring->pending_free)) {
+ req = list_entry(ring->pending_free.next, struct pending_req,
+ free_list);
+ list_del(&req->free_list);
+ }
+ spin_unlock_irqrestore(&ring->pending_free_lock, flags);
+ return req;
+}
+
+/*
+ * Return the 'pending_req' structure back to the freepool. We also
+ * wake up the thread if it was waiting for a free page.
+ */
+static void free_req(struct xen_blkif_ring *ring, struct pending_req *req)
+{
+ unsigned long flags;
+ int was_empty;
+
+ spin_lock_irqsave(&ring->pending_free_lock, flags);
+ was_empty = list_empty(&ring->pending_free);
+ list_add(&req->free_list, &ring->pending_free);
+ spin_unlock_irqrestore(&ring->pending_free_lock, flags);
+ if (was_empty)
+ wake_up(&ring->pending_free_wq);
+}
+
+/*
+ * Routines for managing virtual block devices (vbds).
+ */
+static int xen_vbd_translate(struct phys_req *req, struct xen_blkif *blkif,
+ int operation)
+{
+ struct xen_vbd *vbd = &blkif->vbd;
+ int rc = -EACCES;
+
+ if ((operation != REQ_OP_READ) && vbd->readonly)
+ goto out;
+
+ if (likely(req->nr_sects)) {
+ blkif_sector_t end = req->sector_number + req->nr_sects;
+
+ if (unlikely(end < req->sector_number))
+ goto out;
+ if (unlikely(end > vbd_sz(vbd)))
+ goto out;
+ }
+
+ req->dev = vbd->pdevice;
+ req->bdev = vbd->bdev;
+ rc = 0;
+
+ out:
+ return rc;
+}
+
+static void xen_vbd_resize(struct xen_blkif *blkif)
+{
+ struct xen_vbd *vbd = &blkif->vbd;
+ struct xenbus_transaction xbt;
+ int err;
+ struct xenbus_device *dev = xen_blkbk_xenbus(blkif->be);
+ unsigned long long new_size = vbd_sz(vbd);
+
+ pr_info("VBD Resize: Domid: %d, Device: (%d, %d)\n",
+ blkif->domid, MAJOR(vbd->pdevice), MINOR(vbd->pdevice));
+ pr_info("VBD Resize: new size %llu\n", new_size);
+ vbd->size = new_size;
+again:
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ pr_warn("Error starting transaction\n");
+ return;
+ }
+ err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
+ (unsigned long long)vbd_sz(vbd));
+ if (err) {
+ pr_warn("Error writing new size\n");
+ goto abort;
+ }
+ /*
+ * Write the current state; we will use this to synchronize
+ * the front-end. If the current state is "connected" the
+ * front-end will get the new size information online.
+ */
+ err = xenbus_printf(xbt, dev->nodename, "state", "%d", dev->state);
+ if (err) {
+ pr_warn("Error writing the state\n");
+ goto abort;
+ }
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err == -EAGAIN)
+ goto again;
+ if (err)
+ pr_warn("Error ending transaction\n");
+ return;
+abort:
+ xenbus_transaction_end(xbt, 1);
+}
+
+/*
+ * Notification from the guest OS.
+ */
+static void blkif_notify_work(struct xen_blkif_ring *ring)
+{
+ ring->waiting_reqs = 1;
+ wake_up(&ring->wq);
+}
+
+irqreturn_t xen_blkif_be_int(int irq, void *dev_id)
+{
+ blkif_notify_work(dev_id);
+ return IRQ_HANDLED;
+}
+
+/*
+ * SCHEDULER FUNCTIONS
+ */
+
+static void print_stats(struct xen_blkif_ring *ring)
+{
+ pr_info("(%s): oo %3llu | rd %4llu | wr %4llu | f %4llu"
+ " | ds %4llu | pg: %4u/%4d\n",
+ current->comm, ring->st_oo_req,
+ ring->st_rd_req, ring->st_wr_req,
+ ring->st_f_req, ring->st_ds_req,
+ ring->persistent_gnt_c,
+ xen_blkif_max_pgrants);
+ ring->st_print = jiffies + msecs_to_jiffies(10 * 1000);
+ ring->st_rd_req = 0;
+ ring->st_wr_req = 0;
+ ring->st_oo_req = 0;
+ ring->st_ds_req = 0;
+}
+
+int xen_blkif_schedule(void *arg)
+{
+ struct xen_blkif_ring *ring = arg;
+ struct xen_blkif *blkif = ring->blkif;
+ struct xen_vbd *vbd = &blkif->vbd;
+ unsigned long timeout;
+ int ret;
+
+ set_freezable();
+ while (!kthread_should_stop()) {
+ if (try_to_freeze())
+ continue;
+ if (unlikely(vbd->size != vbd_sz(vbd)))
+ xen_vbd_resize(blkif);
+
+ timeout = msecs_to_jiffies(LRU_INTERVAL);
+
+ timeout = wait_event_interruptible_timeout(
+ ring->wq,
+ ring->waiting_reqs || kthread_should_stop(),
+ timeout);
+ if (timeout == 0)
+ goto purge_gnt_list;
+ timeout = wait_event_interruptible_timeout(
+ ring->pending_free_wq,
+ !list_empty(&ring->pending_free) ||
+ kthread_should_stop(),
+ timeout);
+ if (timeout == 0)
+ goto purge_gnt_list;
+
+ ring->waiting_reqs = 0;
+ smp_mb(); /* clear flag *before* checking for work */
+
+ ret = do_block_io_op(ring);
+ if (ret > 0)
+ ring->waiting_reqs = 1;
+ if (ret == -EACCES)
+ wait_event_interruptible(ring->shutdown_wq,
+ kthread_should_stop());
+
+purge_gnt_list:
+ if (blkif->vbd.feature_gnt_persistent &&
+ time_after(jiffies, ring->next_lru)) {
+ purge_persistent_gnt(ring);
+ ring->next_lru = jiffies + msecs_to_jiffies(LRU_INTERVAL);
+ }
+
+ /* Shrink if we have more than xen_blkif_max_buffer_pages */
+ shrink_free_pagepool(ring, xen_blkif_max_buffer_pages);
+
+ if (log_stats && time_after(jiffies, ring->st_print))
+ print_stats(ring);
+ }
+
+ /* Drain pending purge work */
+ flush_work(&ring->persistent_purge_work);
+
+ if (log_stats)
+ print_stats(ring);
+
+ ring->xenblkd = NULL;
+
+ return 0;
+}
+
+/*
+ * Remove persistent grants and empty the pool of free pages
+ */
+void xen_blkbk_free_caches(struct xen_blkif_ring *ring)
+{
+ /* Free all persistent grant pages */
+ if (!RB_EMPTY_ROOT(&ring->persistent_gnts))
+ free_persistent_gnts(ring, &ring->persistent_gnts,
+ ring->persistent_gnt_c);
+
+ BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts));
+ ring->persistent_gnt_c = 0;
+
+ /* Since we are shutting down remove all pages from the buffer */
+ shrink_free_pagepool(ring, 0 /* All */);
+}
+
+static unsigned int xen_blkbk_unmap_prepare(
+ struct xen_blkif_ring *ring,
+ struct grant_page **pages,
+ unsigned int num,
+ struct gnttab_unmap_grant_ref *unmap_ops,
+ struct page **unmap_pages)
+{
+ unsigned int i, invcount = 0;
+
+ for (i = 0; i < num; i++) {
+ if (pages[i]->persistent_gnt != NULL) {
+ put_persistent_gnt(ring, pages[i]->persistent_gnt);
+ continue;
+ }
+ if (pages[i]->handle == BLKBACK_INVALID_HANDLE)
+ continue;
+ unmap_pages[invcount] = pages[i]->page;
+ gnttab_set_unmap_op(&unmap_ops[invcount], vaddr(pages[i]->page),
+ GNTMAP_host_map, pages[i]->handle);
+ pages[i]->handle = BLKBACK_INVALID_HANDLE;
+ invcount++;
+ }
+
+ return invcount;
+}
+
+static void xen_blkbk_unmap_and_respond_callback(int result, struct gntab_unmap_queue_data *data)
+{
+ struct pending_req *pending_req = (struct pending_req *)(data->data);
+ struct xen_blkif_ring *ring = pending_req->ring;
+ struct xen_blkif *blkif = ring->blkif;
+
+ /* BUG_ON used to reproduce existing behaviour,
+ but is this the best way to deal with this? */
+ BUG_ON(result);
+
+ put_free_pages(ring, data->pages, data->count);
+ make_response(ring, pending_req->id,
+ pending_req->operation, pending_req->status);
+ free_req(ring, pending_req);
+ /*
+ * Make sure the request is freed before releasing blkif,
+ * or there could be a race between free_req and the
+ * cleanup done in xen_blkif_free during shutdown.
+ *
+ * NB: The fact that we might try to wake up pending_free_wq
+ * before drain_complete (in case there's a drain going on)
+ * it's not a problem with our current implementation
+ * because we can assure there's no thread waiting on
+ * pending_free_wq if there's a drain going on, but it has
+ * to be taken into account if the current model is changed.
+ */
+ if (atomic_dec_and_test(&ring->inflight) && atomic_read(&blkif->drain)) {
+ complete(&blkif->drain_complete);
+ }
+ xen_blkif_put(blkif);
+}
+
+static void xen_blkbk_unmap_and_respond(struct pending_req *req)
+{
+ struct gntab_unmap_queue_data* work = &req->gnttab_unmap_data;
+ struct xen_blkif_ring *ring = req->ring;
+ struct grant_page **pages = req->segments;
+ unsigned int invcount;
+
+ invcount = xen_blkbk_unmap_prepare(ring, pages, req->nr_segs,
+ req->unmap, req->unmap_pages);
+
+ work->data = req;
+ work->done = xen_blkbk_unmap_and_respond_callback;
+ work->unmap_ops = req->unmap;
+ work->kunmap_ops = NULL;
+ work->pages = req->unmap_pages;
+ work->count = invcount;
+
+ gnttab_unmap_refs_async(&req->gnttab_unmap_data);
+}
+
+
+/*
+ * Unmap the grant references.
+ *
+ * This could accumulate ops up to the batch size to reduce the number
+ * of hypercalls, but since this is only used in error paths there's
+ * no real need.
+ */
+static void xen_blkbk_unmap(struct xen_blkif_ring *ring,
+ struct grant_page *pages[],
+ int num)
+{
+ struct gnttab_unmap_grant_ref unmap[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *unmap_pages[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ unsigned int invcount = 0;
+ int ret;
+
+ while (num) {
+ unsigned int batch = min(num, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+
+ invcount = xen_blkbk_unmap_prepare(ring, pages, batch,
+ unmap, unmap_pages);
+ if (invcount) {
+ ret = gnttab_unmap_refs(unmap, NULL, unmap_pages, invcount);
+ BUG_ON(ret);
+ put_free_pages(ring, unmap_pages, invcount);
+ }
+ pages += batch;
+ num -= batch;
+ }
+}
+
+static int xen_blkbk_map(struct xen_blkif_ring *ring,
+ struct grant_page *pages[],
+ int num, bool ro)
+{
+ struct gnttab_map_grant_ref map[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct page *pages_to_gnt[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct persistent_gnt *persistent_gnt = NULL;
+ phys_addr_t addr = 0;
+ int i, seg_idx, new_map_idx;
+ int segs_to_map = 0;
+ int ret = 0;
+ int last_map = 0, map_until = 0;
+ int use_persistent_gnts;
+ struct xen_blkif *blkif = ring->blkif;
+
+ use_persistent_gnts = (blkif->vbd.feature_gnt_persistent);
+
+ /*
+ * Fill out preq.nr_sects with proper amount of sectors, and setup
+ * assign map[..] with the PFN of the page in our domain with the
+ * corresponding grant reference for each page.
+ */
+again:
+ for (i = map_until; i < num; i++) {
+ uint32_t flags;
+
+ if (use_persistent_gnts) {
+ persistent_gnt = get_persistent_gnt(
+ ring,
+ pages[i]->gref);
+ }
+
+ if (persistent_gnt) {
+ /*
+ * We are using persistent grants and
+ * the grant is already mapped
+ */
+ pages[i]->page = persistent_gnt->page;
+ pages[i]->persistent_gnt = persistent_gnt;
+ } else {
+ if (get_free_page(ring, &pages[i]->page))
+ goto out_of_memory;
+ addr = vaddr(pages[i]->page);
+ pages_to_gnt[segs_to_map] = pages[i]->page;
+ pages[i]->persistent_gnt = NULL;
+ flags = GNTMAP_host_map;
+ if (!use_persistent_gnts && ro)
+ flags |= GNTMAP_readonly;
+ gnttab_set_map_op(&map[segs_to_map++], addr,
+ flags, pages[i]->gref,
+ blkif->domid);
+ }
+ map_until = i + 1;
+ if (segs_to_map == BLKIF_MAX_SEGMENTS_PER_REQUEST)
+ break;
+ }
+
+ if (segs_to_map) {
+ ret = gnttab_map_refs(map, NULL, pages_to_gnt, segs_to_map);
+ BUG_ON(ret);
+ }
+
+ /*
+ * Now swizzle the MFN in our domain with the MFN from the other domain
+ * so that when we access vaddr(pending_req,i) it has the contents of
+ * the page from the other domain.
+ */
+ for (seg_idx = last_map, new_map_idx = 0; seg_idx < map_until; seg_idx++) {
+ if (!pages[seg_idx]->persistent_gnt) {
+ /* This is a newly mapped grant */
+ BUG_ON(new_map_idx >= segs_to_map);
+ if (unlikely(map[new_map_idx].status != 0)) {
+ pr_debug("invalid buffer -- could not remap it\n");
+ put_free_pages(ring, &pages[seg_idx]->page, 1);
+ pages[seg_idx]->handle = BLKBACK_INVALID_HANDLE;
+ ret |= 1;
+ goto next;
+ }
+ pages[seg_idx]->handle = map[new_map_idx].handle;
+ } else {
+ continue;
+ }
+ if (use_persistent_gnts &&
+ ring->persistent_gnt_c < xen_blkif_max_pgrants) {
+ /*
+ * We are using persistent grants, the grant is
+ * not mapped but we might have room for it.
+ */
+ persistent_gnt = kmalloc(sizeof(struct persistent_gnt),
+ GFP_KERNEL);
+ if (!persistent_gnt) {
+ /*
+ * If we don't have enough memory to
+ * allocate the persistent_gnt struct
+ * map this grant non-persistenly
+ */
+ goto next;
+ }
+ persistent_gnt->gnt = map[new_map_idx].ref;
+ persistent_gnt->handle = map[new_map_idx].handle;
+ persistent_gnt->page = pages[seg_idx]->page;
+ if (add_persistent_gnt(ring,
+ persistent_gnt)) {
+ kfree(persistent_gnt);
+ persistent_gnt = NULL;
+ goto next;
+ }
+ pages[seg_idx]->persistent_gnt = persistent_gnt;
+ pr_debug("grant %u added to the tree of persistent grants, using %u/%u\n",
+ persistent_gnt->gnt, ring->persistent_gnt_c,
+ xen_blkif_max_pgrants);
+ goto next;
+ }
+ if (use_persistent_gnts && !blkif->vbd.overflow_max_grants) {
+ blkif->vbd.overflow_max_grants = 1;
+ pr_debug("domain %u, device %#x is using maximum number of persistent grants\n",
+ blkif->domid, blkif->vbd.handle);
+ }
+ /*
+ * We could not map this grant persistently, so use it as
+ * a non-persistent grant.
+ */
+next:
+ new_map_idx++;
+ }
+ segs_to_map = 0;
+ last_map = map_until;
+ if (map_until != num)
+ goto again;
+
+ return ret;
+
+out_of_memory:
+ pr_alert("%s: out of memory\n", __func__);
+ put_free_pages(ring, pages_to_gnt, segs_to_map);
+ for (i = last_map; i < num; i++)
+ pages[i]->handle = BLKBACK_INVALID_HANDLE;
+ return -ENOMEM;
+}
+
+static int xen_blkbk_map_seg(struct pending_req *pending_req)
+{
+ int rc;
+
+ rc = xen_blkbk_map(pending_req->ring, pending_req->segments,
+ pending_req->nr_segs,
+ (pending_req->operation != BLKIF_OP_READ));
+
+ return rc;
+}
+
+static int xen_blkbk_parse_indirect(struct blkif_request *req,
+ struct pending_req *pending_req,
+ struct seg_buf seg[],
+ struct phys_req *preq)
+{
+ struct grant_page **pages = pending_req->indirect_pages;
+ struct xen_blkif_ring *ring = pending_req->ring;
+ int indirect_grefs, rc, n, nseg, i;
+ struct blkif_request_segment *segments = NULL;
+
+ nseg = pending_req->nr_segs;
+ indirect_grefs = INDIRECT_PAGES(nseg);
+ BUG_ON(indirect_grefs > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
+
+ for (i = 0; i < indirect_grefs; i++)
+ pages[i]->gref = req->u.indirect.indirect_grefs[i];
+
+ rc = xen_blkbk_map(ring, pages, indirect_grefs, true);
+ if (rc)
+ goto unmap;
+
+ for (n = 0, i = 0; n < nseg; n++) {
+ uint8_t first_sect, last_sect;
+
+ if ((n % SEGS_PER_INDIRECT_FRAME) == 0) {
+ /* Map indirect segments */
+ if (segments)
+ kunmap_atomic(segments);
+ segments = kmap_atomic(pages[n/SEGS_PER_INDIRECT_FRAME]->page);
+ }
+ i = n % SEGS_PER_INDIRECT_FRAME;
+
+ pending_req->segments[n]->gref = segments[i].gref;
+
+ first_sect = READ_ONCE(segments[i].first_sect);
+ last_sect = READ_ONCE(segments[i].last_sect);
+ if (last_sect >= (XEN_PAGE_SIZE >> 9) || last_sect < first_sect) {
+ rc = -EINVAL;
+ goto unmap;
+ }
+
+ seg[n].nsec = last_sect - first_sect + 1;
+ seg[n].offset = first_sect << 9;
+ preq->nr_sects += seg[n].nsec;
+ }
+
+unmap:
+ if (segments)
+ kunmap_atomic(segments);
+ xen_blkbk_unmap(ring, pages, indirect_grefs);
+ return rc;
+}
+
+static int dispatch_discard_io(struct xen_blkif_ring *ring,
+ struct blkif_request *req)
+{
+ int err = 0;
+ int status = BLKIF_RSP_OKAY;
+ struct xen_blkif *blkif = ring->blkif;
+ struct block_device *bdev = blkif->vbd.bdev;
+ unsigned long secure;
+ struct phys_req preq;
+
+ xen_blkif_get(blkif);
+
+ preq.sector_number = req->u.discard.sector_number;
+ preq.nr_sects = req->u.discard.nr_sectors;
+
+ err = xen_vbd_translate(&preq, blkif, REQ_OP_WRITE);
+ if (err) {
+ pr_warn("access denied: DISCARD [%llu->%llu] on dev=%04x\n",
+ preq.sector_number,
+ preq.sector_number + preq.nr_sects, blkif->vbd.pdevice);
+ goto fail_response;
+ }
+ ring->st_ds_req++;
+
+ secure = (blkif->vbd.discard_secure &&
+ (req->u.discard.flag & BLKIF_DISCARD_SECURE)) ?
+ BLKDEV_DISCARD_SECURE : 0;
+
+ err = blkdev_issue_discard(bdev, req->u.discard.sector_number,
+ req->u.discard.nr_sectors,
+ GFP_KERNEL, secure);
+fail_response:
+ if (err == -EOPNOTSUPP) {
+ pr_debug("discard op failed, not supported\n");
+ status = BLKIF_RSP_EOPNOTSUPP;
+ } else if (err)
+ status = BLKIF_RSP_ERROR;
+
+ make_response(ring, req->u.discard.id, req->operation, status);
+ xen_blkif_put(blkif);
+ return err;
+}
+
+static int dispatch_other_io(struct xen_blkif_ring *ring,
+ struct blkif_request *req,
+ struct pending_req *pending_req)
+{
+ free_req(ring, pending_req);
+ make_response(ring, req->u.other.id, req->operation,
+ BLKIF_RSP_EOPNOTSUPP);
+ return -EIO;
+}
+
+static void xen_blk_drain_io(struct xen_blkif_ring *ring)
+{
+ struct xen_blkif *blkif = ring->blkif;
+
+ atomic_set(&blkif->drain, 1);
+ do {
+ if (atomic_read(&ring->inflight) == 0)
+ break;
+ wait_for_completion_interruptible_timeout(
+ &blkif->drain_complete, HZ);
+
+ if (!atomic_read(&blkif->drain))
+ break;
+ } while (!kthread_should_stop());
+ atomic_set(&blkif->drain, 0);
+}
+
+static void __end_block_io_op(struct pending_req *pending_req,
+ blk_status_t error)
+{
+ /* An error fails the entire request. */
+ if (pending_req->operation == BLKIF_OP_FLUSH_DISKCACHE &&
+ error == BLK_STS_NOTSUPP) {
+ pr_debug("flush diskcache op failed, not supported\n");
+ xen_blkbk_flush_diskcache(XBT_NIL, pending_req->ring->blkif->be, 0);
+ pending_req->status = BLKIF_RSP_EOPNOTSUPP;
+ } else if (pending_req->operation == BLKIF_OP_WRITE_BARRIER &&
+ error == BLK_STS_NOTSUPP) {
+ pr_debug("write barrier op failed, not supported\n");
+ xen_blkbk_barrier(XBT_NIL, pending_req->ring->blkif->be, 0);
+ pending_req->status = BLKIF_RSP_EOPNOTSUPP;
+ } else if (error) {
+ pr_debug("Buffer not up-to-date at end of operation,"
+ " error=%d\n", error);
+ pending_req->status = BLKIF_RSP_ERROR;
+ }
+
+ /*
+ * If all of the bio's have completed it is time to unmap
+ * the grant references associated with 'request' and provide
+ * the proper response on the ring.
+ */
+ if (atomic_dec_and_test(&pending_req->pendcnt))
+ xen_blkbk_unmap_and_respond(pending_req);
+}
+
+/*
+ * bio callback.
+ */
+static void end_block_io_op(struct bio *bio)
+{
+ __end_block_io_op(bio->bi_private, bio->bi_status);
+ bio_put(bio);
+}
+
+
+
+/*
+ * Function to copy the from the ring buffer the 'struct blkif_request'
+ * (which has the sectors we want, number of them, grant references, etc),
+ * and transmute it to the block API to hand it over to the proper block disk.
+ */
+static int
+__do_block_io_op(struct xen_blkif_ring *ring)
+{
+ union blkif_back_rings *blk_rings = &ring->blk_rings;
+ struct blkif_request req;
+ struct pending_req *pending_req;
+ RING_IDX rc, rp;
+ int more_to_do = 0;
+
+ rc = blk_rings->common.req_cons;
+ rp = blk_rings->common.sring->req_prod;
+ rmb(); /* Ensure we see queued requests up to 'rp'. */
+
+ if (RING_REQUEST_PROD_OVERFLOW(&blk_rings->common, rp)) {
+ rc = blk_rings->common.rsp_prod_pvt;
+ pr_warn("Frontend provided bogus ring requests (%d - %d = %d). Halting ring processing on dev=%04x\n",
+ rp, rc, rp - rc, ring->blkif->vbd.pdevice);
+ return -EACCES;
+ }
+ while (rc != rp) {
+
+ if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
+ break;
+
+ if (kthread_should_stop()) {
+ more_to_do = 1;
+ break;
+ }
+
+ pending_req = alloc_req(ring);
+ if (NULL == pending_req) {
+ ring->st_oo_req++;
+ more_to_do = 1;
+ break;
+ }
+
+ switch (ring->blkif->blk_protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ memcpy(&req, RING_GET_REQUEST(&blk_rings->native, rc), sizeof(req));
+ break;
+ case BLKIF_PROTOCOL_X86_32:
+ blkif_get_x86_32_req(&req, RING_GET_REQUEST(&blk_rings->x86_32, rc));
+ break;
+ case BLKIF_PROTOCOL_X86_64:
+ blkif_get_x86_64_req(&req, RING_GET_REQUEST(&blk_rings->x86_64, rc));
+ break;
+ default:
+ BUG();
+ }
+ blk_rings->common.req_cons = ++rc; /* before make_response() */
+
+ /* Apply all sanity checks to /private copy/ of request. */
+ barrier();
+
+ switch (req.operation) {
+ case BLKIF_OP_READ:
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_WRITE_BARRIER:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ case BLKIF_OP_INDIRECT:
+ if (dispatch_rw_block_io(ring, &req, pending_req))
+ goto done;
+ break;
+ case BLKIF_OP_DISCARD:
+ free_req(ring, pending_req);
+ if (dispatch_discard_io(ring, &req))
+ goto done;
+ break;
+ default:
+ if (dispatch_other_io(ring, &req, pending_req))
+ goto done;
+ break;
+ }
+
+ /* Yield point for this unbounded loop. */
+ cond_resched();
+ }
+done:
+ return more_to_do;
+}
+
+static int
+do_block_io_op(struct xen_blkif_ring *ring)
+{
+ union blkif_back_rings *blk_rings = &ring->blk_rings;
+ int more_to_do;
+
+ do {
+ more_to_do = __do_block_io_op(ring);
+ if (more_to_do)
+ break;
+
+ RING_FINAL_CHECK_FOR_REQUESTS(&blk_rings->common, more_to_do);
+ } while (more_to_do);
+
+ return more_to_do;
+}
+/*
+ * Transmutation of the 'struct blkif_request' to a proper 'struct bio'
+ * and call the 'submit_bio' to pass it to the underlying storage.
+ */
+static int dispatch_rw_block_io(struct xen_blkif_ring *ring,
+ struct blkif_request *req,
+ struct pending_req *pending_req)
+{
+ struct phys_req preq;
+ struct seg_buf *seg = pending_req->seg;
+ unsigned int nseg;
+ struct bio *bio = NULL;
+ struct bio **biolist = pending_req->biolist;
+ int i, nbio = 0;
+ int operation;
+ int operation_flags = 0;
+ struct blk_plug plug;
+ bool drain = false;
+ struct grant_page **pages = pending_req->segments;
+ unsigned short req_operation;
+
+ req_operation = req->operation == BLKIF_OP_INDIRECT ?
+ req->u.indirect.indirect_op : req->operation;
+
+ if ((req->operation == BLKIF_OP_INDIRECT) &&
+ (req_operation != BLKIF_OP_READ) &&
+ (req_operation != BLKIF_OP_WRITE)) {
+ pr_debug("Invalid indirect operation (%u)\n", req_operation);
+ goto fail_response;
+ }
+
+ switch (req_operation) {
+ case BLKIF_OP_READ:
+ ring->st_rd_req++;
+ operation = REQ_OP_READ;
+ break;
+ case BLKIF_OP_WRITE:
+ ring->st_wr_req++;
+ operation = REQ_OP_WRITE;
+ operation_flags = REQ_SYNC | REQ_IDLE;
+ break;
+ case BLKIF_OP_WRITE_BARRIER:
+ drain = true;
+ /* fall through */
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ ring->st_f_req++;
+ operation = REQ_OP_WRITE;
+ operation_flags = REQ_PREFLUSH;
+ break;
+ default:
+ operation = 0; /* make gcc happy */
+ goto fail_response;
+ break;
+ }
+
+ /* Check that the number of segments is sane. */
+ nseg = req->operation == BLKIF_OP_INDIRECT ?
+ req->u.indirect.nr_segments : req->u.rw.nr_segments;
+
+ if (unlikely(nseg == 0 && operation_flags != REQ_PREFLUSH) ||
+ unlikely((req->operation != BLKIF_OP_INDIRECT) &&
+ (nseg > BLKIF_MAX_SEGMENTS_PER_REQUEST)) ||
+ unlikely((req->operation == BLKIF_OP_INDIRECT) &&
+ (nseg > MAX_INDIRECT_SEGMENTS))) {
+ pr_debug("Bad number of segments in request (%d)\n", nseg);
+ /* Haven't submitted any bio's yet. */
+ goto fail_response;
+ }
+
+ preq.nr_sects = 0;
+
+ pending_req->ring = ring;
+ pending_req->id = req->u.rw.id;
+ pending_req->operation = req_operation;
+ pending_req->status = BLKIF_RSP_OKAY;
+ pending_req->nr_segs = nseg;
+
+ if (req->operation != BLKIF_OP_INDIRECT) {
+ preq.dev = req->u.rw.handle;
+ preq.sector_number = req->u.rw.sector_number;
+ for (i = 0; i < nseg; i++) {
+ pages[i]->gref = req->u.rw.seg[i].gref;
+ seg[i].nsec = req->u.rw.seg[i].last_sect -
+ req->u.rw.seg[i].first_sect + 1;
+ seg[i].offset = (req->u.rw.seg[i].first_sect << 9);
+ if ((req->u.rw.seg[i].last_sect >= (XEN_PAGE_SIZE >> 9)) ||
+ (req->u.rw.seg[i].last_sect <
+ req->u.rw.seg[i].first_sect))
+ goto fail_response;
+ preq.nr_sects += seg[i].nsec;
+ }
+ } else {
+ preq.dev = req->u.indirect.handle;
+ preq.sector_number = req->u.indirect.sector_number;
+ if (xen_blkbk_parse_indirect(req, pending_req, seg, &preq))
+ goto fail_response;
+ }
+
+ if (xen_vbd_translate(&preq, ring->blkif, operation) != 0) {
+ pr_debug("access denied: %s of [%llu,%llu] on dev=%04x\n",
+ operation == REQ_OP_READ ? "read" : "write",
+ preq.sector_number,
+ preq.sector_number + preq.nr_sects,
+ ring->blkif->vbd.pdevice);
+ goto fail_response;
+ }
+
+ /*
+ * This check _MUST_ be done after xen_vbd_translate as the preq.bdev
+ * is set there.
+ */
+ for (i = 0; i < nseg; i++) {
+ if (((int)preq.sector_number|(int)seg[i].nsec) &
+ ((bdev_logical_block_size(preq.bdev) >> 9) - 1)) {
+ pr_debug("Misaligned I/O request from domain %d\n",
+ ring->blkif->domid);
+ goto fail_response;
+ }
+ }
+
+ /* Wait on all outstanding I/O's and once that has been completed
+ * issue the flush.
+ */
+ if (drain)
+ xen_blk_drain_io(pending_req->ring);
+
+ /*
+ * If we have failed at this point, we need to undo the M2P override,
+ * set gnttab_set_unmap_op on all of the grant references and perform
+ * the hypercall to unmap the grants - that is all done in
+ * xen_blkbk_unmap.
+ */
+ if (xen_blkbk_map_seg(pending_req))
+ goto fail_flush;
+
+ /*
+ * This corresponding xen_blkif_put is done in __end_block_io_op, or
+ * below (in "!bio") if we are handling a BLKIF_OP_DISCARD.
+ */
+ xen_blkif_get(ring->blkif);
+ atomic_inc(&ring->inflight);
+
+ for (i = 0; i < nseg; i++) {
+ while ((bio == NULL) ||
+ (bio_add_page(bio,
+ pages[i]->page,
+ seg[i].nsec << 9,
+ seg[i].offset) == 0)) {
+
+ int nr_iovecs = min_t(int, (nseg-i), BIO_MAX_PAGES);
+ bio = bio_alloc(GFP_KERNEL, nr_iovecs);
+ if (unlikely(bio == NULL))
+ goto fail_put_bio;
+
+ biolist[nbio++] = bio;
+ bio_set_dev(bio, preq.bdev);
+ bio->bi_private = pending_req;
+ bio->bi_end_io = end_block_io_op;
+ bio->bi_iter.bi_sector = preq.sector_number;
+ bio_set_op_attrs(bio, operation, operation_flags);
+ }
+
+ preq.sector_number += seg[i].nsec;
+ }
+
+ /* This will be hit if the operation was a flush or discard. */
+ if (!bio) {
+ BUG_ON(operation_flags != REQ_PREFLUSH);
+
+ bio = bio_alloc(GFP_KERNEL, 0);
+ if (unlikely(bio == NULL))
+ goto fail_put_bio;
+
+ biolist[nbio++] = bio;
+ bio_set_dev(bio, preq.bdev);
+ bio->bi_private = pending_req;
+ bio->bi_end_io = end_block_io_op;
+ bio_set_op_attrs(bio, operation, operation_flags);
+ }
+
+ atomic_set(&pending_req->pendcnt, nbio);
+ blk_start_plug(&plug);
+
+ for (i = 0; i < nbio; i++)
+ submit_bio(biolist[i]);
+
+ /* Let the I/Os go.. */
+ blk_finish_plug(&plug);
+
+ if (operation == REQ_OP_READ)
+ ring->st_rd_sect += preq.nr_sects;
+ else if (operation == REQ_OP_WRITE)
+ ring->st_wr_sect += preq.nr_sects;
+
+ return 0;
+
+ fail_flush:
+ xen_blkbk_unmap(ring, pending_req->segments,
+ pending_req->nr_segs);
+ fail_response:
+ /* Haven't submitted any bio's yet. */
+ make_response(ring, req->u.rw.id, req_operation, BLKIF_RSP_ERROR);
+ free_req(ring, pending_req);
+ msleep(1); /* back off a bit */
+ return -EIO;
+
+ fail_put_bio:
+ for (i = 0; i < nbio; i++)
+ bio_put(biolist[i]);
+ atomic_set(&pending_req->pendcnt, 1);
+ __end_block_io_op(pending_req, BLK_STS_RESOURCE);
+ msleep(1); /* back off a bit */
+ return -EIO;
+}
+
+
+
+/*
+ * Put a response on the ring on how the operation fared.
+ */
+static void make_response(struct xen_blkif_ring *ring, u64 id,
+ unsigned short op, int st)
+{
+ struct blkif_response *resp;
+ unsigned long flags;
+ union blkif_back_rings *blk_rings;
+ int notify;
+
+ spin_lock_irqsave(&ring->blk_ring_lock, flags);
+ blk_rings = &ring->blk_rings;
+ /* Place on the response ring for the relevant domain. */
+ switch (ring->blkif->blk_protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ resp = RING_GET_RESPONSE(&blk_rings->native,
+ blk_rings->native.rsp_prod_pvt);
+ break;
+ case BLKIF_PROTOCOL_X86_32:
+ resp = RING_GET_RESPONSE(&blk_rings->x86_32,
+ blk_rings->x86_32.rsp_prod_pvt);
+ break;
+ case BLKIF_PROTOCOL_X86_64:
+ resp = RING_GET_RESPONSE(&blk_rings->x86_64,
+ blk_rings->x86_64.rsp_prod_pvt);
+ break;
+ default:
+ BUG();
+ }
+
+ resp->id = id;
+ resp->operation = op;
+ resp->status = st;
+
+ blk_rings->common.rsp_prod_pvt++;
+ RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&blk_rings->common, notify);
+ spin_unlock_irqrestore(&ring->blk_ring_lock, flags);
+ if (notify)
+ notify_remote_via_irq(ring->irq);
+}
+
+static int __init xen_blkif_init(void)
+{
+ int rc = 0;
+
+ if (!xen_domain())
+ return -ENODEV;
+
+ if (xen_blkif_max_ring_order > XENBUS_MAX_RING_GRANT_ORDER) {
+ pr_info("Invalid max_ring_order (%d), will use default max: %d.\n",
+ xen_blkif_max_ring_order, XENBUS_MAX_RING_GRANT_ORDER);
+ xen_blkif_max_ring_order = XENBUS_MAX_RING_GRANT_ORDER;
+ }
+
+ if (xenblk_max_queues == 0)
+ xenblk_max_queues = num_online_cpus();
+
+ rc = xen_blkif_interface_init();
+ if (rc)
+ goto failed_init;
+
+ rc = xen_blkif_xenbus_init();
+ if (rc)
+ goto failed_init;
+
+ failed_init:
+ return rc;
+}
+
+module_init(xen_blkif_init);
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_ALIAS("xen-backend:vbd");
diff --git a/src/kernel/linux/v4.14/drivers/block/xen-blkback/common.h b/src/kernel/linux/v4.14/drivers/block/xen-blkback/common.h
new file mode 100644
index 0000000..ecb35fe
--- /dev/null
+++ b/src/kernel/linux/v4.14/drivers/block/xen-blkback/common.h
@@ -0,0 +1,501 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation; or, when distributed
+ * separately from the Linux kernel or incorporated into other
+ * software packages, subject to the following license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef __XEN_BLKIF__BACKEND__COMMON_H__
+#define __XEN_BLKIF__BACKEND__COMMON_H__
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <linux/vmalloc.h>
+#include <linux/wait.h>
+#include <linux/io.h>
+#include <linux/rbtree.h>
+#include <asm/setup.h>
+#include <asm/pgalloc.h>
+#include <asm/hypervisor.h>
+#include <xen/grant_table.h>
+#include <xen/page.h>
+#include <xen/xenbus.h>
+#include <xen/interface/io/ring.h>
+#include <xen/interface/io/blkif.h>
+#include <xen/interface/io/protocols.h>
+
+extern unsigned int xen_blkif_max_ring_order;
+extern unsigned int xenblk_max_queues;
+/*
+ * This is the maximum number of segments that would be allowed in indirect
+ * requests. This value will also be passed to the frontend.
+ */
+#define MAX_INDIRECT_SEGMENTS 256
+
+/*
+ * Xen use 4K pages. The guest may use different page size (4K or 64K)
+ * Number of Xen pages per segment
+ */
+#define XEN_PAGES_PER_SEGMENT (PAGE_SIZE / XEN_PAGE_SIZE)
+
+#define XEN_PAGES_PER_INDIRECT_FRAME \
+ (XEN_PAGE_SIZE/sizeof(struct blkif_request_segment))
+#define SEGS_PER_INDIRECT_FRAME \
+ (XEN_PAGES_PER_INDIRECT_FRAME / XEN_PAGES_PER_SEGMENT)
+
+#define MAX_INDIRECT_PAGES \
+ ((MAX_INDIRECT_SEGMENTS + SEGS_PER_INDIRECT_FRAME - 1)/SEGS_PER_INDIRECT_FRAME)
+#define INDIRECT_PAGES(_segs) DIV_ROUND_UP(_segs, XEN_PAGES_PER_INDIRECT_FRAME)
+
+/* Not a real protocol. Used to generate ring structs which contain
+ * the elements common to all protocols only. This way we get a
+ * compiler-checkable way to use common struct elements, so we can
+ * avoid using switch(protocol) in a number of places. */
+struct blkif_common_request {
+ char dummy;
+};
+
+/* i386 protocol version */
+
+struct blkif_x86_32_request_rw {
+ uint8_t nr_segments; /* number of segments */
+ blkif_vdev_t handle; /* only for read/write requests */
+ uint64_t id; /* private guest value, echoed in resp */
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request_discard {
+ uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
+ blkif_vdev_t _pad1; /* was "handle" for read/write requests */
+ uint64_t id; /* private guest value, echoed in resp */
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ uint64_t nr_sectors;
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request_other {
+ uint8_t _pad1;
+ blkif_vdev_t _pad2;
+ uint64_t id; /* private guest value, echoed in resp */
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request_indirect {
+ uint8_t indirect_op;
+ uint16_t nr_segments;
+ uint64_t id;
+ blkif_sector_t sector_number;
+ blkif_vdev_t handle;
+ uint16_t _pad1;
+ grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+ /*
+ * The maximum number of indirect segments (and pages) that will
+ * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+ * is also exported to the guest (via xenstore
+ * feature-max-indirect-segments entry), so the frontend knows how
+ * many indirect segments the backend supports.
+ */
+ uint64_t _pad2; /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
+struct blkif_x86_32_request {
+ uint8_t operation; /* BLKIF_OP_??? */
+ union {
+ struct blkif_x86_32_request_rw rw;
+ struct blkif_x86_32_request_discard discard;
+ struct blkif_x86_32_request_other other;
+ struct blkif_x86_32_request_indirect indirect;
+ } u;
+} __attribute__((__packed__));
+
+/* x86_64 protocol version */
+
+struct blkif_x86_64_request_rw {
+ uint8_t nr_segments; /* number of segments */
+ blkif_vdev_t handle; /* only for read/write requests */
+ uint32_t _pad1; /* offsetof(blkif_reqest..,u.rw.id)==8 */
+ uint64_t id;
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request_discard {
+ uint8_t flag; /* BLKIF_DISCARD_SECURE or zero */
+ blkif_vdev_t _pad1; /* was "handle" for read/write requests */
+ uint32_t _pad2; /* offsetof(blkif_..,u.discard.id)==8 */
+ uint64_t id;
+ blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */
+ uint64_t nr_sectors;
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request_other {
+ uint8_t _pad1;
+ blkif_vdev_t _pad2;
+ uint32_t _pad3; /* offsetof(blkif_..,u.discard.id)==8 */
+ uint64_t id; /* private guest value, echoed in resp */
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request_indirect {
+ uint8_t indirect_op;
+ uint16_t nr_segments;
+ uint32_t _pad1; /* offsetof(blkif_..,u.indirect.id)==8 */
+ uint64_t id;
+ blkif_sector_t sector_number;
+ blkif_vdev_t handle;
+ uint16_t _pad2;
+ grant_ref_t indirect_grefs[BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST];
+ /*
+ * The maximum number of indirect segments (and pages) that will
+ * be used is determined by MAX_INDIRECT_SEGMENTS, this value
+ * is also exported to the guest (via xenstore
+ * feature-max-indirect-segments entry), so the frontend knows how
+ * many indirect segments the backend supports.
+ */
+ uint32_t _pad3; /* make it 64 byte aligned */
+} __attribute__((__packed__));
+
+struct blkif_x86_64_request {
+ uint8_t operation; /* BLKIF_OP_??? */
+ union {
+ struct blkif_x86_64_request_rw rw;
+ struct blkif_x86_64_request_discard discard;
+ struct blkif_x86_64_request_other other;
+ struct blkif_x86_64_request_indirect indirect;
+ } u;
+} __attribute__((__packed__));
+
+DEFINE_RING_TYPES(blkif_common, struct blkif_common_request,
+ struct blkif_response);
+DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request,
+ struct blkif_response __packed);
+DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request,
+ struct blkif_response);
+
+union blkif_back_rings {
+ struct blkif_back_ring native;
+ struct blkif_common_back_ring common;
+ struct blkif_x86_32_back_ring x86_32;
+ struct blkif_x86_64_back_ring x86_64;
+};
+
+enum blkif_protocol {
+ BLKIF_PROTOCOL_NATIVE = 1,
+ BLKIF_PROTOCOL_X86_32 = 2,
+ BLKIF_PROTOCOL_X86_64 = 3,
+};
+
+/*
+ * Default protocol if the frontend doesn't specify one.
+ */
+#ifdef CONFIG_X86
+# define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_X86_32
+#else
+# define BLKIF_PROTOCOL_DEFAULT BLKIF_PROTOCOL_NATIVE
+#endif
+
+struct xen_vbd {
+ /* What the domain refers to this vbd as. */
+ blkif_vdev_t handle;
+ /* Non-zero -> read-only */
+ unsigned char readonly;
+ /* VDISK_xxx */
+ unsigned char type;
+ /* phys device that this vbd maps to. */
+ u32 pdevice;
+ struct block_device *bdev;
+ /* Cached size parameter. */
+ sector_t size;
+ unsigned int flush_support:1;
+ unsigned int discard_secure:1;
+ unsigned int feature_gnt_persistent:1;
+ unsigned int overflow_max_grants:1;
+};
+
+struct backend_info;
+
+/* Number of available flags */
+#define PERSISTENT_GNT_FLAGS_SIZE 2
+/* This persistent grant is currently in use */
+#define PERSISTENT_GNT_ACTIVE 0
+/*
+ * This persistent grant has been used, this flag is set when we remove the
+ * PERSISTENT_GNT_ACTIVE, to know that this grant has been used recently.
+ */
+#define PERSISTENT_GNT_WAS_ACTIVE 1
+
+/* Number of requests that we can fit in a ring */
+#define XEN_BLKIF_REQS_PER_PAGE 32
+
+struct persistent_gnt {
+ struct page *page;
+ grant_ref_t gnt;
+ grant_handle_t handle;
+ DECLARE_BITMAP(flags, PERSISTENT_GNT_FLAGS_SIZE);
+ struct rb_node node;
+ struct list_head remove_node;
+};
+
+/* Per-ring information. */
+struct xen_blkif_ring {
+ /* Physical parameters of the comms window. */
+ unsigned int irq;
+ union blkif_back_rings blk_rings;
+ void *blk_ring;
+ /* Private fields. */
+ spinlock_t blk_ring_lock;
+
+ wait_queue_head_t wq;
+ atomic_t inflight;
+ bool active;
+ /* One thread per blkif ring. */
+ struct task_struct *xenblkd;
+ unsigned int waiting_reqs;
+
+ /* List of all 'pending_req' available */
+ struct list_head pending_free;
+ /* And its spinlock. */
+ spinlock_t pending_free_lock;
+ wait_queue_head_t pending_free_wq;
+
+ /* Tree to store persistent grants. */
+ spinlock_t pers_gnts_lock;
+ struct rb_root persistent_gnts;
+ unsigned int persistent_gnt_c;
+ atomic_t persistent_gnt_in_use;
+ unsigned long next_lru;
+
+ /* Statistics. */
+ unsigned long st_print;
+ unsigned long long st_rd_req;
+ unsigned long long st_wr_req;
+ unsigned long long st_oo_req;
+ unsigned long long st_f_req;
+ unsigned long long st_ds_req;
+ unsigned long long st_rd_sect;
+ unsigned long long st_wr_sect;
+
+ /* Used by the kworker that offload work from the persistent purge. */
+ struct list_head persistent_purge_list;
+ struct work_struct persistent_purge_work;
+
+ /* Buffer of free pages to map grant refs. */
+ spinlock_t free_pages_lock;
+ int free_pages_num;
+ struct list_head free_pages;
+
+ struct work_struct free_work;
+ /* Thread shutdown wait queue. */
+ wait_queue_head_t shutdown_wq;
+ struct xen_blkif *blkif;
+};
+
+struct xen_blkif {
+ /* Unique identifier for this interface. */
+ domid_t domid;
+ unsigned int handle;
+ /* Comms information. */
+ enum blkif_protocol blk_protocol;
+ /* The VBD attached to this interface. */
+ struct xen_vbd vbd;
+ /* Back pointer to the backend_info. */
+ struct backend_info *be;
+ atomic_t refcnt;
+ /* for barrier (drain) requests */
+ struct completion drain_complete;
+ atomic_t drain;
+
+ struct work_struct free_work;
+ unsigned int nr_ring_pages;
+ /* All rings for this device. */
+ struct xen_blkif_ring *rings;
+ unsigned int nr_rings;
+};
+
+struct seg_buf {
+ unsigned long offset;
+ unsigned int nsec;
+};
+
+struct grant_page {
+ struct page *page;
+ struct persistent_gnt *persistent_gnt;
+ grant_handle_t handle;
+ grant_ref_t gref;
+};
+
+/*
+ * Each outstanding request that we've passed to the lower device layers has a
+ * 'pending_req' allocated to it. Each buffer_head that completes decrements
+ * the pendcnt towards zero. When it hits zero, the specified domain has a
+ * response queued for it, with the saved 'id' passed back.
+ */
+struct pending_req {
+ struct xen_blkif_ring *ring;
+ u64 id;
+ int nr_segs;
+ atomic_t pendcnt;
+ unsigned short operation;
+ int status;
+ struct list_head free_list;
+ struct grant_page *segments[MAX_INDIRECT_SEGMENTS];
+ /* Indirect descriptors */
+ struct grant_page *indirect_pages[MAX_INDIRECT_PAGES];
+ struct seg_buf seg[MAX_INDIRECT_SEGMENTS];
+ struct bio *biolist[MAX_INDIRECT_SEGMENTS];
+ struct gnttab_unmap_grant_ref unmap[MAX_INDIRECT_SEGMENTS];
+ struct page *unmap_pages[MAX_INDIRECT_SEGMENTS];
+ struct gntab_unmap_queue_data gnttab_unmap_data;
+};
+
+
+#define vbd_sz(_v) ((_v)->bdev->bd_part ? \
+ (_v)->bdev->bd_part->nr_sects : \
+ get_capacity((_v)->bdev->bd_disk))
+
+#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt))
+#define xen_blkif_put(_b) \
+ do { \
+ if (atomic_dec_and_test(&(_b)->refcnt)) \
+ schedule_work(&(_b)->free_work);\
+ } while (0)
+
+struct phys_req {
+ unsigned short dev;
+ blkif_sector_t nr_sects;
+ struct block_device *bdev;
+ blkif_sector_t sector_number;
+};
+int xen_blkif_interface_init(void);
+
+int xen_blkif_xenbus_init(void);
+
+irqreturn_t xen_blkif_be_int(int irq, void *dev_id);
+int xen_blkif_schedule(void *arg);
+int xen_blkif_purge_persistent(void *arg);
+void xen_blkbk_free_caches(struct xen_blkif_ring *ring);
+
+int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
+ struct backend_info *be, int state);
+
+int xen_blkbk_barrier(struct xenbus_transaction xbt,
+ struct backend_info *be, int state);
+struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be);
+void xen_blkbk_unmap_purged_grants(struct work_struct *work);
+
+static inline void blkif_get_x86_32_req(struct blkif_request *dst,
+ struct blkif_x86_32_request *src)
+{
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
+ dst->operation = READ_ONCE(src->operation);
+ switch (dst->operation) {
+ case BLKIF_OP_READ:
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_WRITE_BARRIER:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ dst->u.rw.nr_segments = src->u.rw.nr_segments;
+ dst->u.rw.handle = src->u.rw.handle;
+ dst->u.rw.id = src->u.rw.id;
+ dst->u.rw.sector_number = src->u.rw.sector_number;
+ barrier();
+ if (n > dst->u.rw.nr_segments)
+ n = dst->u.rw.nr_segments;
+ for (i = 0; i < n; i++)
+ dst->u.rw.seg[i] = src->u.rw.seg[i];
+ break;
+ case BLKIF_OP_DISCARD:
+ dst->u.discard.flag = src->u.discard.flag;
+ dst->u.discard.id = src->u.discard.id;
+ dst->u.discard.sector_number = src->u.discard.sector_number;
+ dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
+ break;
+ case BLKIF_OP_INDIRECT:
+ dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+ dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+ dst->u.indirect.handle = src->u.indirect.handle;
+ dst->u.indirect.id = src->u.indirect.id;
+ dst->u.indirect.sector_number = src->u.indirect.sector_number;
+ barrier();
+ j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+ for (i = 0; i < j; i++)
+ dst->u.indirect.indirect_grefs[i] =
+ src->u.indirect.indirect_grefs[i];
+ break;
+ default:
+ /*
+ * Don't know how to translate this op. Only get the
+ * ID so failure can be reported to the frontend.
+ */
+ dst->u.other.id = src->u.other.id;
+ break;
+ }
+}
+
+static inline void blkif_get_x86_64_req(struct blkif_request *dst,
+ struct blkif_x86_64_request *src)
+{
+ int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST, j;
+ dst->operation = READ_ONCE(src->operation);
+ switch (dst->operation) {
+ case BLKIF_OP_READ:
+ case BLKIF_OP_WRITE:
+ case BLKIF_OP_WRITE_BARRIER:
+ case BLKIF_OP_FLUSH_DISKCACHE:
+ dst->u.rw.nr_segments = src->u.rw.nr_segments;
+ dst->u.rw.handle = src->u.rw.handle;
+ dst->u.rw.id = src->u.rw.id;
+ dst->u.rw.sector_number = src->u.rw.sector_number;
+ barrier();
+ if (n > dst->u.rw.nr_segments)
+ n = dst->u.rw.nr_segments;
+ for (i = 0; i < n; i++)
+ dst->u.rw.seg[i] = src->u.rw.seg[i];
+ break;
+ case BLKIF_OP_DISCARD:
+ dst->u.discard.flag = src->u.discard.flag;
+ dst->u.discard.id = src->u.discard.id;
+ dst->u.discard.sector_number = src->u.discard.sector_number;
+ dst->u.discard.nr_sectors = src->u.discard.nr_sectors;
+ break;
+ case BLKIF_OP_INDIRECT:
+ dst->u.indirect.indirect_op = src->u.indirect.indirect_op;
+ dst->u.indirect.nr_segments = src->u.indirect.nr_segments;
+ dst->u.indirect.handle = src->u.indirect.handle;
+ dst->u.indirect.id = src->u.indirect.id;
+ dst->u.indirect.sector_number = src->u.indirect.sector_number;
+ barrier();
+ j = min(MAX_INDIRECT_PAGES, INDIRECT_PAGES(dst->u.indirect.nr_segments));
+ for (i = 0; i < j; i++)
+ dst->u.indirect.indirect_grefs[i] =
+ src->u.indirect.indirect_grefs[i];
+ break;
+ default:
+ /*
+ * Don't know how to translate this op. Only get the
+ * ID so failure can be reported to the frontend.
+ */
+ dst->u.other.id = src->u.other.id;
+ break;
+ }
+}
+
+#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */
diff --git a/src/kernel/linux/v4.14/drivers/block/xen-blkback/xenbus.c b/src/kernel/linux/v4.14/drivers/block/xen-blkback/xenbus.c
new file mode 100644
index 0000000..e9fa4a1
--- /dev/null
+++ b/src/kernel/linux/v4.14/drivers/block/xen-blkback/xenbus.c
@@ -0,0 +1,1126 @@
+/* Xenbus code for blkif backend
+ Copyright (C) 2005 Rusty Russell <rusty@rustcorp.com.au>
+ Copyright (C) 2005 XenSource Ltd
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+*/
+
+#define pr_fmt(fmt) "xen-blkback: " fmt
+
+#include <stdarg.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <xen/events.h>
+#include <xen/grant_table.h>
+#include "common.h"
+
+/* On the XenBus the max length of 'ring-ref%u'. */
+#define RINGREF_NAME_LEN (20)
+
+struct backend_info {
+ struct xenbus_device *dev;
+ struct xen_blkif *blkif;
+ struct xenbus_watch backend_watch;
+ unsigned major;
+ unsigned minor;
+ char *mode;
+};
+
+static struct kmem_cache *xen_blkif_cachep;
+static void connect(struct backend_info *);
+static int connect_ring(struct backend_info *);
+static void backend_changed(struct xenbus_watch *, const char *,
+ const char *);
+static void xen_blkif_free(struct xen_blkif *blkif);
+static void xen_vbd_free(struct xen_vbd *vbd);
+
+struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be)
+{
+ return be->dev;
+}
+
+/*
+ * The last request could free the device from softirq context and
+ * xen_blkif_free() can sleep.
+ */
+static void xen_blkif_deferred_free(struct work_struct *work)
+{
+ struct xen_blkif *blkif;
+
+ blkif = container_of(work, struct xen_blkif, free_work);
+ xen_blkif_free(blkif);
+}
+
+static int blkback_name(struct xen_blkif *blkif, char *buf)
+{
+ char *devpath, *devname;
+ struct xenbus_device *dev = blkif->be->dev;
+
+ devpath = xenbus_read(XBT_NIL, dev->nodename, "dev", NULL);
+ if (IS_ERR(devpath))
+ return PTR_ERR(devpath);
+
+ devname = strstr(devpath, "/dev/");
+ if (devname != NULL)
+ devname += strlen("/dev/");
+ else
+ devname = devpath;
+
+ snprintf(buf, TASK_COMM_LEN, "%d.%s", blkif->domid, devname);
+ kfree(devpath);
+
+ return 0;
+}
+
+static void xen_update_blkif_status(struct xen_blkif *blkif)
+{
+ int err;
+ char name[TASK_COMM_LEN];
+ struct xen_blkif_ring *ring;
+ int i;
+
+ /* Not ready to connect? */
+ if (!blkif->rings || !blkif->rings[0].irq || !blkif->vbd.bdev)
+ return;
+
+ /* Already connected? */
+ if (blkif->be->dev->state == XenbusStateConnected)
+ return;
+
+ /* Attempt to connect: exit if we fail to. */
+ connect(blkif->be);
+ if (blkif->be->dev->state != XenbusStateConnected)
+ return;
+
+ err = blkback_name(blkif, name);
+ if (err) {
+ xenbus_dev_error(blkif->be->dev, err, "get blkback dev name");
+ return;
+ }
+
+ err = filemap_write_and_wait(blkif->vbd.bdev->bd_inode->i_mapping);
+ if (err) {
+ xenbus_dev_error(blkif->be->dev, err, "block flush");
+ return;
+ }
+ invalidate_inode_pages2(blkif->vbd.bdev->bd_inode->i_mapping);
+
+ for (i = 0; i < blkif->nr_rings; i++) {
+ ring = &blkif->rings[i];
+ ring->xenblkd = kthread_run(xen_blkif_schedule, ring, "%s-%d", name, i);
+ if (IS_ERR(ring->xenblkd)) {
+ err = PTR_ERR(ring->xenblkd);
+ ring->xenblkd = NULL;
+ xenbus_dev_fatal(blkif->be->dev, err,
+ "start %s-%d xenblkd", name, i);
+ goto out;
+ }
+ }
+ return;
+
+out:
+ while (--i >= 0) {
+ ring = &blkif->rings[i];
+ kthread_stop(ring->xenblkd);
+ }
+ return;
+}
+
+static int xen_blkif_alloc_rings(struct xen_blkif *blkif)
+{
+ unsigned int r;
+
+ blkif->rings = kzalloc(blkif->nr_rings * sizeof(struct xen_blkif_ring), GFP_KERNEL);
+ if (!blkif->rings)
+ return -ENOMEM;
+
+ for (r = 0; r < blkif->nr_rings; r++) {
+ struct xen_blkif_ring *ring = &blkif->rings[r];
+
+ spin_lock_init(&ring->blk_ring_lock);
+ init_waitqueue_head(&ring->wq);
+ INIT_LIST_HEAD(&ring->pending_free);
+ INIT_LIST_HEAD(&ring->persistent_purge_list);
+ INIT_WORK(&ring->persistent_purge_work, xen_blkbk_unmap_purged_grants);
+ spin_lock_init(&ring->free_pages_lock);
+ INIT_LIST_HEAD(&ring->free_pages);
+
+ spin_lock_init(&ring->pending_free_lock);
+ init_waitqueue_head(&ring->pending_free_wq);
+ init_waitqueue_head(&ring->shutdown_wq);
+ ring->blkif = blkif;
+ ring->st_print = jiffies;
+ ring->active = true;
+ }
+
+ return 0;
+}
+
+static struct xen_blkif *xen_blkif_alloc(domid_t domid)
+{
+ struct xen_blkif *blkif;
+
+ BUILD_BUG_ON(MAX_INDIRECT_PAGES > BLKIF_MAX_INDIRECT_PAGES_PER_REQUEST);
+
+ blkif = kmem_cache_zalloc(xen_blkif_cachep, GFP_KERNEL);
+ if (!blkif)
+ return ERR_PTR(-ENOMEM);
+
+ blkif->domid = domid;
+ atomic_set(&blkif->refcnt, 1);
+ init_completion(&blkif->drain_complete);
+
+ /*
+ * Because freeing back to the cache may be deferred, it is not
+ * safe to unload the module (and hence destroy the cache) until
+ * this has completed. To prevent premature unloading, take an
+ * extra module reference here and release only when the object
+ * has been freed back to the cache.
+ */
+ __module_get(THIS_MODULE);
+ INIT_WORK(&blkif->free_work, xen_blkif_deferred_free);
+
+ return blkif;
+}
+
+static int xen_blkif_map(struct xen_blkif_ring *ring, grant_ref_t *gref,
+ unsigned int nr_grefs, unsigned int evtchn)
+{
+ int err;
+ struct xen_blkif *blkif = ring->blkif;
+
+ /* Already connected through? */
+ if (ring->irq)
+ return 0;
+
+ err = xenbus_map_ring_valloc(blkif->be->dev, gref, nr_grefs,
+ &ring->blk_ring);
+ if (err < 0)
+ return err;
+
+ switch (blkif->blk_protocol) {
+ case BLKIF_PROTOCOL_NATIVE:
+ {
+ struct blkif_sring *sring;
+ sring = (struct blkif_sring *)ring->blk_ring;
+ BACK_RING_INIT(&ring->blk_rings.native, sring,
+ XEN_PAGE_SIZE * nr_grefs);
+ break;
+ }
+ case BLKIF_PROTOCOL_X86_32:
+ {
+ struct blkif_x86_32_sring *sring_x86_32;
+ sring_x86_32 = (struct blkif_x86_32_sring *)ring->blk_ring;
+ BACK_RING_INIT(&ring->blk_rings.x86_32, sring_x86_32,
+ XEN_PAGE_SIZE * nr_grefs);
+ break;
+ }
+ case BLKIF_PROTOCOL_X86_64:
+ {
+ struct blkif_x86_64_sring *sring_x86_64;
+ sring_x86_64 = (struct blkif_x86_64_sring *)ring->blk_ring;
+ BACK_RING_INIT(&ring->blk_rings.x86_64, sring_x86_64,
+ XEN_PAGE_SIZE * nr_grefs);
+ break;
+ }
+ default:
+ BUG();
+ }
+
+ err = bind_interdomain_evtchn_to_irqhandler(blkif->domid, evtchn,
+ xen_blkif_be_int, 0,
+ "blkif-backend", ring);
+ if (err < 0) {
+ xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
+ ring->blk_rings.common.sring = NULL;
+ return err;
+ }
+ ring->irq = err;
+
+ return 0;
+}
+
+static int xen_blkif_disconnect(struct xen_blkif *blkif)
+{
+ struct pending_req *req, *n;
+ unsigned int j, r;
+ bool busy = false;
+
+ for (r = 0; r < blkif->nr_rings; r++) {
+ struct xen_blkif_ring *ring = &blkif->rings[r];
+ unsigned int i = 0;
+
+ if (!ring->active)
+ continue;
+
+ if (ring->xenblkd) {
+ kthread_stop(ring->xenblkd);
+ wake_up(&ring->shutdown_wq);
+ }
+
+ /* The above kthread_stop() guarantees that at this point we
+ * don't have any discard_io or other_io requests. So, checking
+ * for inflight IO is enough.
+ */
+ if (atomic_read(&ring->inflight) > 0) {
+ busy = true;
+ continue;
+ }
+
+ if (ring->irq) {
+ unbind_from_irqhandler(ring->irq, ring);
+ ring->irq = 0;
+ }
+
+ if (ring->blk_rings.common.sring) {
+ xenbus_unmap_ring_vfree(blkif->be->dev, ring->blk_ring);
+ ring->blk_rings.common.sring = NULL;
+ }
+
+ /* Remove all persistent grants and the cache of ballooned pages. */
+ xen_blkbk_free_caches(ring);
+
+ /* Check that there is no request in use */
+ list_for_each_entry_safe(req, n, &ring->pending_free, free_list) {
+ list_del(&req->free_list);
+
+ for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++)
+ kfree(req->segments[j]);
+
+ for (j = 0; j < MAX_INDIRECT_PAGES; j++)
+ kfree(req->indirect_pages[j]);
+
+ kfree(req);
+ i++;
+ }
+
+ BUG_ON(atomic_read(&ring->persistent_gnt_in_use) != 0);
+ BUG_ON(!list_empty(&ring->persistent_purge_list));
+ BUG_ON(!RB_EMPTY_ROOT(&ring->persistent_gnts));
+ BUG_ON(!list_empty(&ring->free_pages));
+ BUG_ON(ring->free_pages_num != 0);
+ BUG_ON(ring->persistent_gnt_c != 0);
+ WARN_ON(i != (XEN_BLKIF_REQS_PER_PAGE * blkif->nr_ring_pages));
+ ring->active = false;
+ }
+ if (busy)
+ return -EBUSY;
+
+ blkif->nr_ring_pages = 0;
+ /*
+ * blkif->rings was allocated in connect_ring, so we should free it in
+ * here.
+ */
+ kfree(blkif->rings);
+ blkif->rings = NULL;
+ blkif->nr_rings = 0;
+
+ return 0;
+}
+
+static void xen_blkif_free(struct xen_blkif *blkif)
+{
+ WARN_ON(xen_blkif_disconnect(blkif));
+ xen_vbd_free(&blkif->vbd);
+ kfree(blkif->be->mode);
+ kfree(blkif->be);
+
+ /* Make sure everything is drained before shutting down */
+ kmem_cache_free(xen_blkif_cachep, blkif);
+ module_put(THIS_MODULE);
+}
+
+int __init xen_blkif_interface_init(void)
+{
+ xen_blkif_cachep = kmem_cache_create("blkif_cache",
+ sizeof(struct xen_blkif),
+ 0, 0, NULL);
+ if (!xen_blkif_cachep)
+ return -ENOMEM;
+
+ return 0;
+}
+
+/*
+ * sysfs interface for VBD I/O requests
+ */
+
+#define VBD_SHOW_ALLRING(name, format) \
+ static ssize_t show_##name(struct device *_dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+ { \
+ struct xenbus_device *dev = to_xenbus_device(_dev); \
+ struct backend_info *be = dev_get_drvdata(&dev->dev); \
+ struct xen_blkif *blkif = be->blkif; \
+ unsigned int i; \
+ unsigned long long result = 0; \
+ \
+ if (!blkif->rings) \
+ goto out; \
+ \
+ for (i = 0; i < blkif->nr_rings; i++) { \
+ struct xen_blkif_ring *ring = &blkif->rings[i]; \
+ \
+ result += ring->st_##name; \
+ } \
+ \
+out: \
+ return sprintf(buf, format, result); \
+ } \
+ static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
+
+VBD_SHOW_ALLRING(oo_req, "%llu\n");
+VBD_SHOW_ALLRING(rd_req, "%llu\n");
+VBD_SHOW_ALLRING(wr_req, "%llu\n");
+VBD_SHOW_ALLRING(f_req, "%llu\n");
+VBD_SHOW_ALLRING(ds_req, "%llu\n");
+VBD_SHOW_ALLRING(rd_sect, "%llu\n");
+VBD_SHOW_ALLRING(wr_sect, "%llu\n");
+
+static struct attribute *xen_vbdstat_attrs[] = {
+ &dev_attr_oo_req.attr,
+ &dev_attr_rd_req.attr,
+ &dev_attr_wr_req.attr,
+ &dev_attr_f_req.attr,
+ &dev_attr_ds_req.attr,
+ &dev_attr_rd_sect.attr,
+ &dev_attr_wr_sect.attr,
+ NULL
+};
+
+static const struct attribute_group xen_vbdstat_group = {
+ .name = "statistics",
+ .attrs = xen_vbdstat_attrs,
+};
+
+#define VBD_SHOW(name, format, args...) \
+ static ssize_t show_##name(struct device *_dev, \
+ struct device_attribute *attr, \
+ char *buf) \
+ { \
+ struct xenbus_device *dev = to_xenbus_device(_dev); \
+ struct backend_info *be = dev_get_drvdata(&dev->dev); \
+ \
+ return sprintf(buf, format, ##args); \
+ } \
+ static DEVICE_ATTR(name, S_IRUGO, show_##name, NULL)
+
+VBD_SHOW(physical_device, "%x:%x\n", be->major, be->minor);
+VBD_SHOW(mode, "%s\n", be->mode);
+
+static int xenvbd_sysfs_addif(struct xenbus_device *dev)
+{
+ int error;
+
+ error = device_create_file(&dev->dev, &dev_attr_physical_device);
+ if (error)
+ goto fail1;
+
+ error = device_create_file(&dev->dev, &dev_attr_mode);
+ if (error)
+ goto fail2;
+
+ error = sysfs_create_group(&dev->dev.kobj, &xen_vbdstat_group);
+ if (error)
+ goto fail3;
+
+ return 0;
+
+fail3: sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group);
+fail2: device_remove_file(&dev->dev, &dev_attr_mode);
+fail1: device_remove_file(&dev->dev, &dev_attr_physical_device);
+ return error;
+}
+
+static void xenvbd_sysfs_delif(struct xenbus_device *dev)
+{
+ sysfs_remove_group(&dev->dev.kobj, &xen_vbdstat_group);
+ device_remove_file(&dev->dev, &dev_attr_mode);
+ device_remove_file(&dev->dev, &dev_attr_physical_device);
+}
+
+
+static void xen_vbd_free(struct xen_vbd *vbd)
+{
+ if (vbd->bdev)
+ blkdev_put(vbd->bdev, vbd->readonly ? FMODE_READ : FMODE_WRITE);
+ vbd->bdev = NULL;
+}
+
+static int xen_vbd_create(struct xen_blkif *blkif, blkif_vdev_t handle,
+ unsigned major, unsigned minor, int readonly,
+ int cdrom)
+{
+ struct xen_vbd *vbd;
+ struct block_device *bdev;
+ struct request_queue *q;
+
+ vbd = &blkif->vbd;
+ vbd->handle = handle;
+ vbd->readonly = readonly;
+ vbd->type = 0;
+
+ vbd->pdevice = MKDEV(major, minor);
+
+ bdev = blkdev_get_by_dev(vbd->pdevice, vbd->readonly ?
+ FMODE_READ : FMODE_WRITE, NULL);
+
+ if (IS_ERR(bdev)) {
+ pr_warn("xen_vbd_create: device %08x could not be opened\n",
+ vbd->pdevice);
+ return -ENOENT;
+ }
+
+ vbd->bdev = bdev;
+ if (vbd->bdev->bd_disk == NULL) {
+ pr_warn("xen_vbd_create: device %08x doesn't exist\n",
+ vbd->pdevice);
+ xen_vbd_free(vbd);
+ return -ENOENT;
+ }
+ vbd->size = vbd_sz(vbd);
+
+ if (vbd->bdev->bd_disk->flags & GENHD_FL_CD || cdrom)
+ vbd->type |= VDISK_CDROM;
+ if (vbd->bdev->bd_disk->flags & GENHD_FL_REMOVABLE)
+ vbd->type |= VDISK_REMOVABLE;
+
+ q = bdev_get_queue(bdev);
+ if (q && test_bit(QUEUE_FLAG_WC, &q->queue_flags))
+ vbd->flush_support = true;
+
+ if (q && blk_queue_secure_erase(q))
+ vbd->discard_secure = true;
+
+ pr_debug("Successful creation of handle=%04x (dom=%u)\n",
+ handle, blkif->domid);
+ return 0;
+}
+static int xen_blkbk_remove(struct xenbus_device *dev)
+{
+ struct backend_info *be = dev_get_drvdata(&dev->dev);
+
+ pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
+
+ if (be->major || be->minor)
+ xenvbd_sysfs_delif(dev);
+
+ if (be->backend_watch.node) {
+ unregister_xenbus_watch(&be->backend_watch);
+ kfree(be->backend_watch.node);
+ be->backend_watch.node = NULL;
+ }
+
+ dev_set_drvdata(&dev->dev, NULL);
+
+ if (be->blkif) {
+ xen_blkif_disconnect(be->blkif);
+
+ /* Put the reference we set in xen_blkif_alloc(). */
+ xen_blkif_put(be->blkif);
+ }
+
+ return 0;
+}
+
+int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt,
+ struct backend_info *be, int state)
+{
+ struct xenbus_device *dev = be->dev;
+ int err;
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-flush-cache",
+ "%d", state);
+ if (err)
+ dev_warn(&dev->dev, "writing feature-flush-cache (%d)", err);
+
+ return err;
+}
+
+static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ struct xen_blkif *blkif = be->blkif;
+ int err;
+ int state = 0;
+ struct block_device *bdev = be->blkif->vbd.bdev;
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ if (!xenbus_read_unsigned(dev->nodename, "discard-enable", 1))
+ return;
+
+ if (blk_queue_discard(q)) {
+ err = xenbus_printf(xbt, dev->nodename,
+ "discard-granularity", "%u",
+ q->limits.discard_granularity);
+ if (err) {
+ dev_warn(&dev->dev, "writing discard-granularity (%d)", err);
+ return;
+ }
+ err = xenbus_printf(xbt, dev->nodename,
+ "discard-alignment", "%u",
+ q->limits.discard_alignment);
+ if (err) {
+ dev_warn(&dev->dev, "writing discard-alignment (%d)", err);
+ return;
+ }
+ state = 1;
+ /* Optional. */
+ err = xenbus_printf(xbt, dev->nodename,
+ "discard-secure", "%d",
+ blkif->vbd.discard_secure);
+ if (err) {
+ dev_warn(&dev->dev, "writing discard-secure (%d)", err);
+ return;
+ }
+ }
+ err = xenbus_printf(xbt, dev->nodename, "feature-discard",
+ "%d", state);
+ if (err)
+ dev_warn(&dev->dev, "writing feature-discard (%d)", err);
+}
+int xen_blkbk_barrier(struct xenbus_transaction xbt,
+ struct backend_info *be, int state)
+{
+ struct xenbus_device *dev = be->dev;
+ int err;
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-barrier",
+ "%d", state);
+ if (err)
+ dev_warn(&dev->dev, "writing feature-barrier (%d)", err);
+
+ return err;
+}
+
+/*
+ * Entry point to this code when a new device is created. Allocate the basic
+ * structures, and watch the store waiting for the hotplug scripts to tell us
+ * the device's physical major and minor numbers. Switch to InitWait.
+ */
+static int xen_blkbk_probe(struct xenbus_device *dev,
+ const struct xenbus_device_id *id)
+{
+ int err;
+ struct backend_info *be = kzalloc(sizeof(struct backend_info),
+ GFP_KERNEL);
+
+ /* match the pr_debug in xen_blkbk_remove */
+ pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
+
+ if (!be) {
+ xenbus_dev_fatal(dev, -ENOMEM,
+ "allocating backend structure");
+ return -ENOMEM;
+ }
+ be->dev = dev;
+ dev_set_drvdata(&dev->dev, be);
+
+ be->blkif = xen_blkif_alloc(dev->otherend_id);
+ if (IS_ERR(be->blkif)) {
+ err = PTR_ERR(be->blkif);
+ be->blkif = NULL;
+ xenbus_dev_fatal(dev, err, "creating block interface");
+ goto fail;
+ }
+
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "feature-max-indirect-segments", "%u",
+ MAX_INDIRECT_SEGMENTS);
+ if (err)
+ dev_warn(&dev->dev,
+ "writing %s/feature-max-indirect-segments (%d)",
+ dev->nodename, err);
+
+ /* Multi-queue: advertise how many queues are supported by us.*/
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "multi-queue-max-queues", "%u", xenblk_max_queues);
+ if (err)
+ pr_warn("Error writing multi-queue-max-queues\n");
+
+ /* setup back pointer */
+ be->blkif->be = be;
+
+ err = xenbus_watch_pathfmt(dev, &be->backend_watch, backend_changed,
+ "%s/%s", dev->nodename, "physical-device");
+ if (err)
+ goto fail;
+
+ err = xenbus_printf(XBT_NIL, dev->nodename, "max-ring-page-order", "%u",
+ xen_blkif_max_ring_order);
+ if (err)
+ pr_warn("%s write out 'max-ring-page-order' failed\n", __func__);
+
+ err = xenbus_switch_state(dev, XenbusStateInitWait);
+ if (err)
+ goto fail;
+
+ return 0;
+
+fail:
+ pr_warn("%s failed\n", __func__);
+ xen_blkbk_remove(dev);
+ return err;
+}
+
+
+/*
+ * Callback received when the hotplug scripts have placed the physical-device
+ * node. Read it and the mode node, and create a vbd. If the frontend is
+ * ready, connect.
+ */
+static void backend_changed(struct xenbus_watch *watch,
+ const char *path, const char *token)
+{
+ int err;
+ unsigned major;
+ unsigned minor;
+ struct backend_info *be
+ = container_of(watch, struct backend_info, backend_watch);
+ struct xenbus_device *dev = be->dev;
+ int cdrom = 0;
+ unsigned long handle;
+ char *device_type;
+
+ pr_debug("%s %p %d\n", __func__, dev, dev->otherend_id);
+
+ err = xenbus_scanf(XBT_NIL, dev->nodename, "physical-device", "%x:%x",
+ &major, &minor);
+ if (XENBUS_EXIST_ERR(err)) {
+ /*
+ * Since this watch will fire once immediately after it is
+ * registered, we expect this. Ignore it, and wait for the
+ * hotplug scripts.
+ */
+ return;
+ }
+ if (err != 2) {
+ xenbus_dev_fatal(dev, err, "reading physical-device");
+ return;
+ }
+
+ if (be->major | be->minor) {
+ if (be->major != major || be->minor != minor)
+ pr_warn("changing physical device (from %x:%x to %x:%x) not supported.\n",
+ be->major, be->minor, major, minor);
+ return;
+ }
+
+ be->mode = xenbus_read(XBT_NIL, dev->nodename, "mode", NULL);
+ if (IS_ERR(be->mode)) {
+ err = PTR_ERR(be->mode);
+ be->mode = NULL;
+ xenbus_dev_fatal(dev, err, "reading mode");
+ return;
+ }
+
+ device_type = xenbus_read(XBT_NIL, dev->otherend, "device-type", NULL);
+ if (!IS_ERR(device_type)) {
+ cdrom = strcmp(device_type, "cdrom") == 0;
+ kfree(device_type);
+ }
+
+ /* Front end dir is a number, which is used as the handle. */
+ err = kstrtoul(strrchr(dev->otherend, '/') + 1, 0, &handle);
+ if (err) {
+ kfree(be->mode);
+ be->mode = NULL;
+ return;
+ }
+
+ be->major = major;
+ be->minor = minor;
+
+ err = xen_vbd_create(be->blkif, handle, major, minor,
+ !strchr(be->mode, 'w'), cdrom);
+
+ if (err)
+ xenbus_dev_fatal(dev, err, "creating vbd structure");
+ else {
+ err = xenvbd_sysfs_addif(dev);
+ if (err) {
+ xen_vbd_free(&be->blkif->vbd);
+ xenbus_dev_fatal(dev, err, "creating sysfs entries");
+ }
+ }
+
+ if (err) {
+ kfree(be->mode);
+ be->mode = NULL;
+ be->major = 0;
+ be->minor = 0;
+ } else {
+ /* We're potentially connected now */
+ xen_update_blkif_status(be->blkif);
+ }
+}
+
+
+/*
+ * Callback received when the frontend's state changes.
+ */
+static void frontend_changed(struct xenbus_device *dev,
+ enum xenbus_state frontend_state)
+{
+ struct backend_info *be = dev_get_drvdata(&dev->dev);
+ int err;
+
+ pr_debug("%s %p %s\n", __func__, dev, xenbus_strstate(frontend_state));
+
+ switch (frontend_state) {
+ case XenbusStateInitialising:
+ if (dev->state == XenbusStateClosed) {
+ pr_info("%s: prepare for reconnect\n", dev->nodename);
+ xenbus_switch_state(dev, XenbusStateInitWait);
+ }
+ break;
+
+ case XenbusStateInitialised:
+ case XenbusStateConnected:
+ /*
+ * Ensure we connect even when two watches fire in
+ * close succession and we miss the intermediate value
+ * of frontend_state.
+ */
+ if (dev->state == XenbusStateConnected)
+ break;
+
+ /*
+ * Enforce precondition before potential leak point.
+ * xen_blkif_disconnect() is idempotent.
+ */
+ err = xen_blkif_disconnect(be->blkif);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "pending I/O");
+ break;
+ }
+
+ err = connect_ring(be);
+ if (err) {
+ /*
+ * Clean up so that memory resources can be used by
+ * other devices. connect_ring reported already error.
+ */
+ xen_blkif_disconnect(be->blkif);
+ break;
+ }
+ xen_update_blkif_status(be->blkif);
+ break;
+
+ case XenbusStateClosing:
+ xenbus_switch_state(dev, XenbusStateClosing);
+ break;
+
+ case XenbusStateClosed:
+ xen_blkif_disconnect(be->blkif);
+ xenbus_switch_state(dev, XenbusStateClosed);
+ if (xenbus_dev_is_online(dev))
+ break;
+ /* fall through */
+ /* if not online */
+ case XenbusStateUnknown:
+ /* implies xen_blkif_disconnect() via xen_blkbk_remove() */
+ device_unregister(&dev->dev);
+ break;
+
+ default:
+ xenbus_dev_fatal(dev, -EINVAL, "saw state %d at frontend",
+ frontend_state);
+ break;
+ }
+}
+
+
+/* ** Connection ** */
+
+
+/*
+ * Write the physical details regarding the block device to the store, and
+ * switch to Connected state.
+ */
+static void connect(struct backend_info *be)
+{
+ struct xenbus_transaction xbt;
+ int err;
+ struct xenbus_device *dev = be->dev;
+
+ pr_debug("%s %s\n", __func__, dev->otherend);
+
+ /* Supply the information about the device the frontend needs */
+again:
+ err = xenbus_transaction_start(&xbt);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "starting transaction");
+ return;
+ }
+
+ /* If we can't advertise it is OK. */
+ xen_blkbk_flush_diskcache(xbt, be, be->blkif->vbd.flush_support);
+
+ xen_blkbk_discard(xbt, be);
+
+ xen_blkbk_barrier(xbt, be, be->blkif->vbd.flush_support);
+
+ err = xenbus_printf(xbt, dev->nodename, "feature-persistent", "%u", 1);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "writing %s/feature-persistent",
+ dev->nodename);
+ goto abort;
+ }
+
+ err = xenbus_printf(xbt, dev->nodename, "sectors", "%llu",
+ (unsigned long long)vbd_sz(&be->blkif->vbd));
+ if (err) {
+ xenbus_dev_fatal(dev, err, "writing %s/sectors",
+ dev->nodename);
+ goto abort;
+ }
+
+ /* FIXME: use a typename instead */
+ err = xenbus_printf(xbt, dev->nodename, "info", "%u",
+ be->blkif->vbd.type |
+ (be->blkif->vbd.readonly ? VDISK_READONLY : 0));
+ if (err) {
+ xenbus_dev_fatal(dev, err, "writing %s/info",
+ dev->nodename);
+ goto abort;
+ }
+ err = xenbus_printf(xbt, dev->nodename, "sector-size", "%lu",
+ (unsigned long)
+ bdev_logical_block_size(be->blkif->vbd.bdev));
+ if (err) {
+ xenbus_dev_fatal(dev, err, "writing %s/sector-size",
+ dev->nodename);
+ goto abort;
+ }
+ err = xenbus_printf(xbt, dev->nodename, "physical-sector-size", "%u",
+ bdev_physical_block_size(be->blkif->vbd.bdev));
+ if (err)
+ xenbus_dev_error(dev, err, "writing %s/physical-sector-size",
+ dev->nodename);
+
+ err = xenbus_transaction_end(xbt, 0);
+ if (err == -EAGAIN)
+ goto again;
+ if (err)
+ xenbus_dev_fatal(dev, err, "ending transaction");
+
+ err = xenbus_switch_state(dev, XenbusStateConnected);
+ if (err)
+ xenbus_dev_fatal(dev, err, "%s: switching to Connected state",
+ dev->nodename);
+
+ return;
+ abort:
+ xenbus_transaction_end(xbt, 1);
+}
+
+/*
+ * Each ring may have multi pages, depends on "ring-page-order".
+ */
+static int read_per_ring_refs(struct xen_blkif_ring *ring, const char *dir)
+{
+ unsigned int ring_ref[XENBUS_MAX_RING_GRANTS];
+ struct pending_req *req, *n;
+ int err, i, j;
+ struct xen_blkif *blkif = ring->blkif;
+ struct xenbus_device *dev = blkif->be->dev;
+ unsigned int ring_page_order, nr_grefs, evtchn;
+
+ err = xenbus_scanf(XBT_NIL, dir, "event-channel", "%u",
+ &evtchn);
+ if (err != 1) {
+ err = -EINVAL;
+ xenbus_dev_fatal(dev, err, "reading %s/event-channel", dir);
+ return err;
+ }
+
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "ring-page-order", "%u",
+ &ring_page_order);
+ if (err != 1) {
+ err = xenbus_scanf(XBT_NIL, dir, "ring-ref", "%u", &ring_ref[0]);
+ if (err != 1) {
+ err = -EINVAL;
+ xenbus_dev_fatal(dev, err, "reading %s/ring-ref", dir);
+ return err;
+ }
+ nr_grefs = 1;
+ } else {
+ unsigned int i;
+
+ if (ring_page_order > xen_blkif_max_ring_order) {
+ err = -EINVAL;
+ xenbus_dev_fatal(dev, err, "%s/request %d ring page order exceed max:%d",
+ dir, ring_page_order,
+ xen_blkif_max_ring_order);
+ return err;
+ }
+
+ nr_grefs = 1 << ring_page_order;
+ for (i = 0; i < nr_grefs; i++) {
+ char ring_ref_name[RINGREF_NAME_LEN];
+
+ snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u", i);
+ err = xenbus_scanf(XBT_NIL, dir, ring_ref_name,
+ "%u", &ring_ref[i]);
+ if (err != 1) {
+ err = -EINVAL;
+ xenbus_dev_fatal(dev, err, "reading %s/%s",
+ dir, ring_ref_name);
+ return err;
+ }
+ }
+ }
+ blkif->nr_ring_pages = nr_grefs;
+
+ err = -ENOMEM;
+ for (i = 0; i < nr_grefs * XEN_BLKIF_REQS_PER_PAGE; i++) {
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+ if (!req)
+ goto fail;
+ list_add_tail(&req->free_list, &ring->pending_free);
+ for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
+ req->segments[j] = kzalloc(sizeof(*req->segments[0]), GFP_KERNEL);
+ if (!req->segments[j])
+ goto fail;
+ }
+ for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
+ req->indirect_pages[j] = kzalloc(sizeof(*req->indirect_pages[0]),
+ GFP_KERNEL);
+ if (!req->indirect_pages[j])
+ goto fail;
+ }
+ }
+
+ /* Map the shared frame, irq etc. */
+ err = xen_blkif_map(ring, ring_ref, nr_grefs, evtchn);
+ if (err) {
+ xenbus_dev_fatal(dev, err, "mapping ring-ref port %u", evtchn);
+ goto fail;
+ }
+
+ return 0;
+
+fail:
+ list_for_each_entry_safe(req, n, &ring->pending_free, free_list) {
+ list_del(&req->free_list);
+ for (j = 0; j < MAX_INDIRECT_SEGMENTS; j++) {
+ if (!req->segments[j])
+ break;
+ kfree(req->segments[j]);
+ }
+ for (j = 0; j < MAX_INDIRECT_PAGES; j++) {
+ if (!req->indirect_pages[j])
+ break;
+ kfree(req->indirect_pages[j]);
+ }
+ kfree(req);
+ }
+ return err;
+}
+
+static int connect_ring(struct backend_info *be)
+{
+ struct xenbus_device *dev = be->dev;
+ unsigned int pers_grants;
+ char protocol[64] = "";
+ int err, i;
+ char *xspath;
+ size_t xspathsize;
+ const size_t xenstore_path_ext_size = 11; /* sufficient for "/queue-NNN" */
+ unsigned int requested_num_queues = 0;
+
+ pr_debug("%s %s\n", __func__, dev->otherend);
+
+ be->blkif->blk_protocol = BLKIF_PROTOCOL_DEFAULT;
+ err = xenbus_scanf(XBT_NIL, dev->otherend, "protocol",
+ "%63s", protocol);
+ if (err <= 0)
+ strcpy(protocol, "unspecified, assuming default");
+ else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_NATIVE))
+ be->blkif->blk_protocol = BLKIF_PROTOCOL_NATIVE;
+ else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_32))
+ be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_32;
+ else if (0 == strcmp(protocol, XEN_IO_PROTO_ABI_X86_64))
+ be->blkif->blk_protocol = BLKIF_PROTOCOL_X86_64;
+ else {
+ xenbus_dev_fatal(dev, err, "unknown fe protocol %s", protocol);
+ return -ENOSYS;
+ }
+ pers_grants = xenbus_read_unsigned(dev->otherend, "feature-persistent",
+ 0);
+ be->blkif->vbd.feature_gnt_persistent = pers_grants;
+ be->blkif->vbd.overflow_max_grants = 0;
+
+ /*
+ * Read the number of hardware queues from frontend.
+ */
+ requested_num_queues = xenbus_read_unsigned(dev->otherend,
+ "multi-queue-num-queues",
+ 1);
+ if (requested_num_queues > xenblk_max_queues
+ || requested_num_queues == 0) {
+ /* Buggy or malicious guest. */
+ xenbus_dev_fatal(dev, err,
+ "guest requested %u queues, exceeding the maximum of %u.",
+ requested_num_queues, xenblk_max_queues);
+ return -ENOSYS;
+ }
+ be->blkif->nr_rings = requested_num_queues;
+ if (xen_blkif_alloc_rings(be->blkif))
+ return -ENOMEM;
+
+ pr_info("%s: using %d queues, protocol %d (%s) %s\n", dev->nodename,
+ be->blkif->nr_rings, be->blkif->blk_protocol, protocol,
+ pers_grants ? "persistent grants" : "");
+
+ if (be->blkif->nr_rings == 1)
+ return read_per_ring_refs(&be->blkif->rings[0], dev->otherend);
+ else {
+ xspathsize = strlen(dev->otherend) + xenstore_path_ext_size;
+ xspath = kmalloc(xspathsize, GFP_KERNEL);
+ if (!xspath) {
+ xenbus_dev_fatal(dev, -ENOMEM, "reading ring references");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < be->blkif->nr_rings; i++) {
+ memset(xspath, 0, xspathsize);
+ snprintf(xspath, xspathsize, "%s/queue-%u", dev->otherend, i);
+ err = read_per_ring_refs(&be->blkif->rings[i], xspath);
+ if (err) {
+ kfree(xspath);
+ return err;
+ }
+ }
+ kfree(xspath);
+ }
+ return 0;
+}
+
+static const struct xenbus_device_id xen_blkbk_ids[] = {
+ { "vbd" },
+ { "" }
+};
+
+static struct xenbus_driver xen_blkbk_driver = {
+ .ids = xen_blkbk_ids,
+ .probe = xen_blkbk_probe,
+ .remove = xen_blkbk_remove,
+ .otherend_changed = frontend_changed
+};
+
+int xen_blkif_xenbus_init(void)
+{
+ return xenbus_register_backend(&xen_blkbk_driver);
+}