zte's code,first commit
Change-Id: I9a04da59e459a9bc0d67f101f700d9d7dc8d681b
diff --git a/ap/os/linux/linux-3.4.x/drivers/md/dm-kcopyd.c b/ap/os/linux/linux-3.4.x/drivers/md/dm-kcopyd.c
new file mode 100644
index 0000000..bed444c
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/drivers/md/dm-kcopyd.c
@@ -0,0 +1,756 @@
+/*
+ * Copyright (C) 2002 Sistina Software (UK) Limited.
+ * Copyright (C) 2006 Red Hat GmbH
+ *
+ * This file is released under the GPL.
+ *
+ * Kcopyd provides a simple interface for copying an area of one
+ * block-device to one or more other block-devices, with an asynchronous
+ * completion notification.
+ */
+
+#include <linux/types.h>
+#include <linux/atomic.h>
+#include <linux/blkdev.h>
+#include <linux/fs.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/mempool.h>
+#include <linux/module.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/device-mapper.h>
+#include <linux/dm-kcopyd.h>
+
+#include "dm.h"
+
+#define SUB_JOB_SIZE 128
+#define SPLIT_COUNT 8
+#define MIN_JOBS 8
+#define RESERVE_PAGES (DIV_ROUND_UP(SUB_JOB_SIZE << SECTOR_SHIFT, PAGE_SIZE))
+
+/*-----------------------------------------------------------------
+ * Each kcopyd client has its own little pool of preallocated
+ * pages for kcopyd io.
+ *---------------------------------------------------------------*/
+struct dm_kcopyd_client {
+ struct page_list *pages;
+ unsigned nr_reserved_pages;
+ unsigned nr_free_pages;
+
+ struct dm_io_client *io_client;
+
+ wait_queue_head_t destroyq;
+ atomic_t nr_jobs;
+
+ mempool_t *job_pool;
+
+ struct workqueue_struct *kcopyd_wq;
+ struct work_struct kcopyd_work;
+
+/*
+ * We maintain three lists of jobs:
+ *
+ * i) jobs waiting for pages
+ * ii) jobs that have pages, and are waiting for the io to be issued.
+ * iii) jobs that have completed.
+ *
+ * All three of these are protected by job_lock.
+ */
+ spinlock_t job_lock;
+ struct list_head complete_jobs;
+ struct list_head io_jobs;
+ struct list_head pages_jobs;
+};
+
+static struct page_list zero_page_list;
+
+static void wake(struct dm_kcopyd_client *kc)
+{
+ queue_work(kc->kcopyd_wq, &kc->kcopyd_work);
+}
+
+/*
+ * Obtain one page for the use of kcopyd.
+ */
+static struct page_list *alloc_pl(gfp_t gfp)
+{
+ struct page_list *pl;
+
+ pl = kmalloc(sizeof(*pl), gfp);
+ if (!pl)
+ return NULL;
+
+ pl->page = alloc_page(gfp);
+ if (!pl->page) {
+ kfree(pl);
+ return NULL;
+ }
+
+ return pl;
+}
+
+static void free_pl(struct page_list *pl)
+{
+ __free_page(pl->page);
+ kfree(pl);
+}
+
+/*
+ * Add the provided pages to a client's free page list, releasing
+ * back to the system any beyond the reserved_pages limit.
+ */
+static void kcopyd_put_pages(struct dm_kcopyd_client *kc, struct page_list *pl)
+{
+ struct page_list *next;
+
+ do {
+ next = pl->next;
+
+ if (kc->nr_free_pages >= kc->nr_reserved_pages)
+ free_pl(pl);
+ else {
+ pl->next = kc->pages;
+ kc->pages = pl;
+ kc->nr_free_pages++;
+ }
+
+ pl = next;
+ } while (pl);
+}
+
+static int kcopyd_get_pages(struct dm_kcopyd_client *kc,
+ unsigned int nr, struct page_list **pages)
+{
+ struct page_list *pl;
+
+ *pages = NULL;
+
+ do {
+ pl = alloc_pl(__GFP_NOWARN | __GFP_NORETRY);
+ if (unlikely(!pl)) {
+ /* Use reserved pages */
+ pl = kc->pages;
+ if (unlikely(!pl))
+ goto out_of_memory;
+ kc->pages = pl->next;
+ kc->nr_free_pages--;
+ }
+ pl->next = *pages;
+ *pages = pl;
+ } while (--nr);
+
+ return 0;
+
+out_of_memory:
+ if (*pages)
+ kcopyd_put_pages(kc, *pages);
+ return -ENOMEM;
+}
+
+/*
+ * These three functions resize the page pool.
+ */
+static void drop_pages(struct page_list *pl)
+{
+ struct page_list *next;
+
+ while (pl) {
+ next = pl->next;
+ free_pl(pl);
+ pl = next;
+ }
+}
+
+/*
+ * Allocate and reserve nr_pages for the use of a specific client.
+ */
+static int client_reserve_pages(struct dm_kcopyd_client *kc, unsigned nr_pages)
+{
+ unsigned i;
+ struct page_list *pl = NULL, *next;
+
+ for (i = 0; i < nr_pages; i++) {
+ next = alloc_pl(GFP_KERNEL);
+ if (!next) {
+ if (pl)
+ drop_pages(pl);
+ return -ENOMEM;
+ }
+ next->next = pl;
+ pl = next;
+ }
+
+ kc->nr_reserved_pages += nr_pages;
+ kcopyd_put_pages(kc, pl);
+
+ return 0;
+}
+
+static void client_free_pages(struct dm_kcopyd_client *kc)
+{
+ BUG_ON(kc->nr_free_pages != kc->nr_reserved_pages);
+ drop_pages(kc->pages);
+ kc->pages = NULL;
+ kc->nr_free_pages = kc->nr_reserved_pages = 0;
+}
+
+/*-----------------------------------------------------------------
+ * kcopyd_jobs need to be allocated by the *clients* of kcopyd,
+ * for this reason we use a mempool to prevent the client from
+ * ever having to do io (which could cause a deadlock).
+ *---------------------------------------------------------------*/
+struct kcopyd_job {
+ struct dm_kcopyd_client *kc;
+ struct list_head list;
+ unsigned long flags;
+
+ /*
+ * Error state of the job.
+ */
+ int read_err;
+ unsigned long write_err;
+
+ /*
+ * Either READ or WRITE
+ */
+ int rw;
+ struct dm_io_region source;
+
+ /*
+ * The destinations for the transfer.
+ */
+ unsigned int num_dests;
+ struct dm_io_region dests[DM_KCOPYD_MAX_REGIONS];
+
+ struct page_list *pages;
+
+ /*
+ * Set this to ensure you are notified when the job has
+ * completed. 'context' is for callback to use.
+ */
+ dm_kcopyd_notify_fn fn;
+ void *context;
+
+ /*
+ * These fields are only used if the job has been split
+ * into more manageable parts.
+ */
+ struct mutex lock;
+ atomic_t sub_jobs;
+ sector_t progress;
+
+ struct kcopyd_job *master_job;
+};
+
+static struct kmem_cache *_job_cache;
+
+int __init dm_kcopyd_init(void)
+{
+ _job_cache = kmem_cache_create("kcopyd_job",
+ sizeof(struct kcopyd_job) * (SPLIT_COUNT + 1),
+ __alignof__(struct kcopyd_job), 0, NULL);
+ if (!_job_cache)
+ return -ENOMEM;
+
+ zero_page_list.next = &zero_page_list;
+ zero_page_list.page = ZERO_PAGE(0);
+
+ return 0;
+}
+
+void dm_kcopyd_exit(void)
+{
+ kmem_cache_destroy(_job_cache);
+ _job_cache = NULL;
+}
+
+/*
+ * Functions to push and pop a job onto the head of a given job
+ * list.
+ */
+static struct kcopyd_job *pop(struct list_head *jobs,
+ struct dm_kcopyd_client *kc)
+{
+ struct kcopyd_job *job = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&kc->job_lock, flags);
+
+ if (!list_empty(jobs)) {
+ job = list_entry(jobs->next, struct kcopyd_job, list);
+ list_del(&job->list);
+ }
+ spin_unlock_irqrestore(&kc->job_lock, flags);
+
+ return job;
+}
+
+static void push(struct list_head *jobs, struct kcopyd_job *job)
+{
+ unsigned long flags;
+ struct dm_kcopyd_client *kc = job->kc;
+
+ spin_lock_irqsave(&kc->job_lock, flags);
+ list_add_tail(&job->list, jobs);
+ spin_unlock_irqrestore(&kc->job_lock, flags);
+}
+
+
+static void push_head(struct list_head *jobs, struct kcopyd_job *job)
+{
+ unsigned long flags;
+ struct dm_kcopyd_client *kc = job->kc;
+
+ spin_lock_irqsave(&kc->job_lock, flags);
+ list_add(&job->list, jobs);
+ spin_unlock_irqrestore(&kc->job_lock, flags);
+}
+
+/*
+ * These three functions process 1 item from the corresponding
+ * job list.
+ *
+ * They return:
+ * < 0: error
+ * 0: success
+ * > 0: can't process yet.
+ */
+static int run_complete_job(struct kcopyd_job *job)
+{
+ void *context = job->context;
+ int read_err = job->read_err;
+ unsigned long write_err = job->write_err;
+ dm_kcopyd_notify_fn fn = job->fn;
+ struct dm_kcopyd_client *kc = job->kc;
+
+ if (job->pages && job->pages != &zero_page_list)
+ kcopyd_put_pages(kc, job->pages);
+ /*
+ * If this is the master job, the sub jobs have already
+ * completed so we can free everything.
+ */
+ if (job->master_job == job)
+ mempool_free(job, kc->job_pool);
+ fn(read_err, write_err, context);
+
+ if (atomic_dec_and_test(&kc->nr_jobs))
+ wake_up(&kc->destroyq);
+
+ return 0;
+}
+
+static void complete_io(unsigned long error, void *context)
+{
+ struct kcopyd_job *job = (struct kcopyd_job *) context;
+ struct dm_kcopyd_client *kc = job->kc;
+
+ if (error) {
+ if (job->rw == WRITE)
+ job->write_err |= error;
+ else
+ job->read_err = 1;
+
+ if (!test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) {
+ push(&kc->complete_jobs, job);
+ wake(kc);
+ return;
+ }
+ }
+
+ if (job->rw == WRITE)
+ push(&kc->complete_jobs, job);
+
+ else {
+ job->rw = WRITE;
+ push(&kc->io_jobs, job);
+ }
+
+ wake(kc);
+}
+
+/*
+ * Request io on as many buffer heads as we can currently get for
+ * a particular job.
+ */
+static int run_io_job(struct kcopyd_job *job)
+{
+ int r;
+ struct dm_io_request io_req = {
+ .bi_rw = job->rw,
+ .mem.type = DM_IO_PAGE_LIST,
+ .mem.ptr.pl = job->pages,
+ .mem.offset = 0,
+ .notify.fn = complete_io,
+ .notify.context = job,
+ .client = job->kc->io_client,
+ };
+
+ if (job->rw == READ)
+ r = dm_io(&io_req, 1, &job->source, NULL);
+ else
+ r = dm_io(&io_req, job->num_dests, job->dests, NULL);
+
+ return r;
+}
+
+static int run_pages_job(struct kcopyd_job *job)
+{
+ int r;
+ unsigned nr_pages = dm_div_up(job->dests[0].count, PAGE_SIZE >> 9);
+
+ r = kcopyd_get_pages(job->kc, nr_pages, &job->pages);
+ if (!r) {
+ /* this job is ready for io */
+ push(&job->kc->io_jobs, job);
+ return 0;
+ }
+
+ if (r == -ENOMEM)
+ /* can't complete now */
+ return 1;
+
+ return r;
+}
+
+/*
+ * Run through a list for as long as possible. Returns the count
+ * of successful jobs.
+ */
+static int process_jobs(struct list_head *jobs, struct dm_kcopyd_client *kc,
+ int (*fn) (struct kcopyd_job *))
+{
+ struct kcopyd_job *job;
+ int r, count = 0;
+
+ while ((job = pop(jobs, kc))) {
+
+ r = fn(job);
+
+ if (r < 0) {
+ /* error this rogue job */
+ if (job->rw == WRITE)
+ job->write_err = (unsigned long) -1L;
+ else
+ job->read_err = 1;
+ push(&kc->complete_jobs, job);
+ break;
+ }
+
+ if (r > 0) {
+ /*
+ * We couldn't service this job ATM, so
+ * push this job back onto the list.
+ */
+ push_head(jobs, job);
+ break;
+ }
+
+ count++;
+ }
+
+ return count;
+}
+
+/*
+ * kcopyd does this every time it's woken up.
+ */
+static void do_work(struct work_struct *work)
+{
+ struct dm_kcopyd_client *kc = container_of(work,
+ struct dm_kcopyd_client, kcopyd_work);
+ struct blk_plug plug;
+
+ /*
+ * The order that these are called is *very* important.
+ * complete jobs can free some pages for pages jobs.
+ * Pages jobs when successful will jump onto the io jobs
+ * list. io jobs call wake when they complete and it all
+ * starts again.
+ */
+ blk_start_plug(&plug);
+ process_jobs(&kc->complete_jobs, kc, run_complete_job);
+ process_jobs(&kc->pages_jobs, kc, run_pages_job);
+ process_jobs(&kc->io_jobs, kc, run_io_job);
+ blk_finish_plug(&plug);
+}
+
+/*
+ * If we are copying a small region we just dispatch a single job
+ * to do the copy, otherwise the io has to be split up into many
+ * jobs.
+ */
+static void dispatch_job(struct kcopyd_job *job)
+{
+ struct dm_kcopyd_client *kc = job->kc;
+ atomic_inc(&kc->nr_jobs);
+ if (unlikely(!job->source.count))
+ push(&kc->complete_jobs, job);
+ else if (job->pages == &zero_page_list)
+ push(&kc->io_jobs, job);
+ else
+ push(&kc->pages_jobs, job);
+ wake(kc);
+}
+
+static void segment_complete(int read_err, unsigned long write_err,
+ void *context)
+{
+ /* FIXME: tidy this function */
+ sector_t progress = 0;
+ sector_t count = 0;
+ struct kcopyd_job *sub_job = (struct kcopyd_job *) context;
+ struct kcopyd_job *job = sub_job->master_job;
+ struct dm_kcopyd_client *kc = job->kc;
+
+ mutex_lock(&job->lock);
+
+ /* update the error */
+ if (read_err)
+ job->read_err = 1;
+
+ if (write_err)
+ job->write_err |= write_err;
+
+ /*
+ * Only dispatch more work if there hasn't been an error.
+ */
+ if ((!job->read_err && !job->write_err) ||
+ test_bit(DM_KCOPYD_IGNORE_ERROR, &job->flags)) {
+ /* get the next chunk of work */
+ progress = job->progress;
+ count = job->source.count - progress;
+ if (count) {
+ if (count > SUB_JOB_SIZE)
+ count = SUB_JOB_SIZE;
+
+ job->progress += count;
+ }
+ }
+ mutex_unlock(&job->lock);
+
+ if (count) {
+ int i;
+
+ *sub_job = *job;
+ sub_job->source.sector += progress;
+ sub_job->source.count = count;
+
+ for (i = 0; i < job->num_dests; i++) {
+ sub_job->dests[i].sector += progress;
+ sub_job->dests[i].count = count;
+ }
+
+ sub_job->fn = segment_complete;
+ sub_job->context = sub_job;
+ dispatch_job(sub_job);
+
+ } else if (atomic_dec_and_test(&job->sub_jobs)) {
+
+ /*
+ * Queue the completion callback to the kcopyd thread.
+ *
+ * Some callers assume that all the completions are called
+ * from a single thread and don't race with each other.
+ *
+ * We must not call the callback directly here because this
+ * code may not be executing in the thread.
+ */
+ push(&kc->complete_jobs, job);
+ wake(kc);
+ }
+}
+
+/*
+ * Create some sub jobs to share the work between them.
+ */
+static void split_job(struct kcopyd_job *master_job)
+{
+ int i;
+
+ atomic_inc(&master_job->kc->nr_jobs);
+
+ atomic_set(&master_job->sub_jobs, SPLIT_COUNT);
+ for (i = 0; i < SPLIT_COUNT; i++) {
+ master_job[i + 1].master_job = master_job;
+ segment_complete(0, 0u, &master_job[i + 1]);
+ }
+}
+
+int dm_kcopyd_copy(struct dm_kcopyd_client *kc, struct dm_io_region *from,
+ unsigned int num_dests, struct dm_io_region *dests,
+ unsigned int flags, dm_kcopyd_notify_fn fn, void *context)
+{
+ struct kcopyd_job *job;
+
+ /*
+ * Allocate an array of jobs consisting of one master job
+ * followed by SPLIT_COUNT sub jobs.
+ */
+ job = mempool_alloc(kc->job_pool, GFP_NOIO);
+
+ /*
+ * set up for the read.
+ */
+ job->kc = kc;
+ job->flags = flags;
+ job->read_err = 0;
+ job->write_err = 0;
+
+ job->num_dests = num_dests;
+ memcpy(&job->dests, dests, sizeof(*dests) * num_dests);
+
+ if (from) {
+ job->source = *from;
+ job->pages = NULL;
+ job->rw = READ;
+ } else {
+ memset(&job->source, 0, sizeof job->source);
+ job->source.count = job->dests[0].count;
+ job->pages = &zero_page_list;
+ job->rw = WRITE;
+ }
+
+ job->fn = fn;
+ job->context = context;
+ job->master_job = job;
+
+ if (job->source.count <= SUB_JOB_SIZE)
+ dispatch_job(job);
+ else {
+ mutex_init(&job->lock);
+ job->progress = 0;
+ split_job(job);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(dm_kcopyd_copy);
+
+int dm_kcopyd_zero(struct dm_kcopyd_client *kc,
+ unsigned num_dests, struct dm_io_region *dests,
+ unsigned flags, dm_kcopyd_notify_fn fn, void *context)
+{
+ return dm_kcopyd_copy(kc, NULL, num_dests, dests, flags, fn, context);
+}
+EXPORT_SYMBOL(dm_kcopyd_zero);
+
+void *dm_kcopyd_prepare_callback(struct dm_kcopyd_client *kc,
+ dm_kcopyd_notify_fn fn, void *context)
+{
+ struct kcopyd_job *job;
+
+ job = mempool_alloc(kc->job_pool, GFP_NOIO);
+
+ memset(job, 0, sizeof(struct kcopyd_job));
+ job->kc = kc;
+ job->fn = fn;
+ job->context = context;
+ job->master_job = job;
+
+ atomic_inc(&kc->nr_jobs);
+
+ return job;
+}
+EXPORT_SYMBOL(dm_kcopyd_prepare_callback);
+
+void dm_kcopyd_do_callback(void *j, int read_err, unsigned long write_err)
+{
+ struct kcopyd_job *job = j;
+ struct dm_kcopyd_client *kc = job->kc;
+
+ job->read_err = read_err;
+ job->write_err = write_err;
+
+ push(&kc->complete_jobs, job);
+ wake(kc);
+}
+EXPORT_SYMBOL(dm_kcopyd_do_callback);
+
+/*
+ * Cancels a kcopyd job, eg. someone might be deactivating a
+ * mirror.
+ */
+#if 0
+int kcopyd_cancel(struct kcopyd_job *job, int block)
+{
+ /* FIXME: finish */
+ return -1;
+}
+#endif /* 0 */
+
+/*-----------------------------------------------------------------
+ * Client setup
+ *---------------------------------------------------------------*/
+struct dm_kcopyd_client *dm_kcopyd_client_create(void)
+{
+ int r = -ENOMEM;
+ struct dm_kcopyd_client *kc;
+
+ kc = kmalloc(sizeof(*kc), GFP_KERNEL);
+ if (!kc)
+ return ERR_PTR(-ENOMEM);
+
+ spin_lock_init(&kc->job_lock);
+ INIT_LIST_HEAD(&kc->complete_jobs);
+ INIT_LIST_HEAD(&kc->io_jobs);
+ INIT_LIST_HEAD(&kc->pages_jobs);
+
+ kc->job_pool = mempool_create_slab_pool(MIN_JOBS, _job_cache);
+ if (!kc->job_pool)
+ goto bad_slab;
+
+ INIT_WORK(&kc->kcopyd_work, do_work);
+ kc->kcopyd_wq = alloc_workqueue("kcopyd",
+ WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);
+ if (!kc->kcopyd_wq)
+ goto bad_workqueue;
+
+ kc->pages = NULL;
+ kc->nr_reserved_pages = kc->nr_free_pages = 0;
+ r = client_reserve_pages(kc, RESERVE_PAGES);
+ if (r)
+ goto bad_client_pages;
+
+ kc->io_client = dm_io_client_create();
+ if (IS_ERR(kc->io_client)) {
+ r = PTR_ERR(kc->io_client);
+ goto bad_io_client;
+ }
+
+ init_waitqueue_head(&kc->destroyq);
+ atomic_set(&kc->nr_jobs, 0);
+
+ return kc;
+
+bad_io_client:
+ client_free_pages(kc);
+bad_client_pages:
+ destroy_workqueue(kc->kcopyd_wq);
+bad_workqueue:
+ mempool_destroy(kc->job_pool);
+bad_slab:
+ kfree(kc);
+
+ return ERR_PTR(r);
+}
+EXPORT_SYMBOL(dm_kcopyd_client_create);
+
+void dm_kcopyd_client_destroy(struct dm_kcopyd_client *kc)
+{
+ /* Wait for completion of all jobs submitted by this client. */
+ wait_event(kc->destroyq, !atomic_read(&kc->nr_jobs));
+
+ BUG_ON(!list_empty(&kc->complete_jobs));
+ BUG_ON(!list_empty(&kc->io_jobs));
+ BUG_ON(!list_empty(&kc->pages_jobs));
+ destroy_workqueue(kc->kcopyd_wq);
+ dm_io_client_destroy(kc->io_client);
+ client_free_pages(kc);
+ mempool_destroy(kc->job_pool);
+ kfree(kc);
+}
+EXPORT_SYMBOL(dm_kcopyd_client_destroy);