[T106][ZXW-22]7520V3SCV2.01.01.02P42U09_VEC_V0.8_AP_VEC origin source commit
Change-Id: Ic6e05d89ecd62fc34f82b23dcf306c93764aec4b
diff --git a/ap/os/linux/linux-3.4.x/block/blk-settings.c b/ap/os/linux/linux-3.4.x/block/blk-settings.c
new file mode 100644
index 0000000..14f1d30
--- /dev/null
+++ b/ap/os/linux/linux-3.4.x/block/blk-settings.c
@@ -0,0 +1,823 @@
+/*
+ * Functions related to setting various queue properties from drivers
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
+#include <linux/gcd.h>
+#include <linux/lcm.h>
+#include <linux/jiffies.h>
+#include <linux/gfp.h>
+
+#include "blk.h"
+
+unsigned long blk_max_low_pfn;
+EXPORT_SYMBOL(blk_max_low_pfn);
+
+unsigned long blk_max_pfn;
+
+/**
+ * blk_queue_prep_rq - set a prepare_request function for queue
+ * @q: queue
+ * @pfn: prepare_request function
+ *
+ * It's possible for a queue to register a prepare_request callback which
+ * is invoked before the request is handed to the request_fn. The goal of
+ * the function is to prepare a request for I/O, it can be used to build a
+ * cdb from the request data for instance.
+ *
+ */
+void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
+{
+ q->prep_rq_fn = pfn;
+}
+EXPORT_SYMBOL(blk_queue_prep_rq);
+
+/**
+ * blk_queue_unprep_rq - set an unprepare_request function for queue
+ * @q: queue
+ * @ufn: unprepare_request function
+ *
+ * It's possible for a queue to register an unprepare_request callback
+ * which is invoked before the request is finally completed. The goal
+ * of the function is to deallocate any data that was allocated in the
+ * prepare_request callback.
+ *
+ */
+void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn)
+{
+ q->unprep_rq_fn = ufn;
+}
+EXPORT_SYMBOL(blk_queue_unprep_rq);
+
+/**
+ * blk_queue_merge_bvec - set a merge_bvec function for queue
+ * @q: queue
+ * @mbfn: merge_bvec_fn
+ *
+ * Usually queues have static limitations on the max sectors or segments that
+ * we can put in a request. Stacking drivers may have some settings that
+ * are dynamic, and thus we have to query the queue whether it is ok to
+ * add a new bio_vec to a bio at a given offset or not. If the block device
+ * has such limitations, it needs to register a merge_bvec_fn to control
+ * the size of bio's sent to it. Note that a block device *must* allow a
+ * single page to be added to an empty bio. The block device driver may want
+ * to use the bio_split() function to deal with these bio's. By default
+ * no merge_bvec_fn is defined for a queue, and only the fixed limits are
+ * honored.
+ */
+void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
+{
+ q->merge_bvec_fn = mbfn;
+}
+EXPORT_SYMBOL(blk_queue_merge_bvec);
+
+void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
+{
+ q->softirq_done_fn = fn;
+}
+EXPORT_SYMBOL(blk_queue_softirq_done);
+
+void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout)
+{
+ q->rq_timeout = timeout;
+}
+EXPORT_SYMBOL_GPL(blk_queue_rq_timeout);
+
+void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn)
+{
+ q->rq_timed_out_fn = fn;
+}
+EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out);
+
+void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn)
+{
+ q->lld_busy_fn = fn;
+}
+EXPORT_SYMBOL_GPL(blk_queue_lld_busy);
+
+/**
+ * blk_set_default_limits - reset limits to default values
+ * @lim: the queue_limits structure to reset
+ *
+ * Description:
+ * Returns a queue_limit struct to its default state.
+ */
+void blk_set_default_limits(struct queue_limits *lim)
+{
+ lim->max_segments = BLK_MAX_SEGMENTS;
+ lim->max_integrity_segments = 0;
+ lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
+ lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
+ lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
+ lim->max_discard_sectors = 0;
+ lim->discard_granularity = 0;
+ lim->discard_alignment = 0;
+ lim->discard_misaligned = 0;
+ lim->discard_zeroes_data = 0;
+ lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
+ lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
+ lim->alignment_offset = 0;
+ lim->io_opt = 0;
+ lim->misaligned = 0;
+ lim->cluster = 1;
+}
+EXPORT_SYMBOL(blk_set_default_limits);
+
+/**
+ * blk_set_stacking_limits - set default limits for stacking devices
+ * @lim: the queue_limits structure to reset
+ *
+ * Description:
+ * Returns a queue_limit struct to its default state. Should be used
+ * by stacking drivers like DM that have no internal limits.
+ */
+void blk_set_stacking_limits(struct queue_limits *lim)
+{
+ blk_set_default_limits(lim);
+
+ /* Inherit limits from component devices */
+ lim->discard_zeroes_data = 1;
+ lim->max_segments = USHRT_MAX;
+ lim->max_hw_sectors = UINT_MAX;
+ lim->max_segment_size = UINT_MAX;
+
+ lim->max_sectors = BLK_DEF_MAX_SECTORS;
+}
+EXPORT_SYMBOL(blk_set_stacking_limits);
+
+/**
+ * blk_queue_make_request - define an alternate make_request function for a device
+ * @q: the request queue for the device to be affected
+ * @mfn: the alternate make_request function
+ *
+ * Description:
+ * The normal way for &struct bios to be passed to a device
+ * driver is for them to be collected into requests on a request
+ * queue, and then to allow the device driver to select requests
+ * off that queue when it is ready. This works well for many block
+ * devices. However some block devices (typically virtual devices
+ * such as md or lvm) do not benefit from the processing on the
+ * request queue, and are served best by having the requests passed
+ * directly to them. This can be achieved by providing a function
+ * to blk_queue_make_request().
+ *
+ * Caveat:
+ * The driver that does this *must* be able to deal appropriately
+ * with buffers in "highmemory". This can be accomplished by either calling
+ * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
+ * blk_queue_bounce() to create a buffer in normal memory.
+ **/
+void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn)
+{
+ /*
+ * set defaults
+ */
+ q->nr_requests = BLKDEV_MAX_RQ;
+
+ q->make_request_fn = mfn;
+ blk_queue_dma_alignment(q, 511);
+ blk_queue_congestion_threshold(q);
+ q->nr_batching = BLK_BATCH_REQ;
+
+ blk_set_default_limits(&q->limits);
+
+ /*
+ * by default assume old behaviour and bounce for any highmem page
+ */
+ blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
+}
+EXPORT_SYMBOL(blk_queue_make_request);
+
+/**
+ * blk_queue_bounce_limit - set bounce buffer limit for queue
+ * @q: the request queue for the device
+ * @dma_mask: the maximum address the device can handle
+ *
+ * Description:
+ * Different hardware can have different requirements as to what pages
+ * it can do I/O directly to. A low level driver can call
+ * blk_queue_bounce_limit to have lower memory pages allocated as bounce
+ * buffers for doing I/O to pages residing above @dma_mask.
+ **/
+void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask)
+{
+ unsigned long b_pfn = dma_mask >> PAGE_SHIFT;
+ int dma = 0;
+
+ q->bounce_gfp = GFP_NOIO;
+#if BITS_PER_LONG == 64
+ /*
+ * Assume anything <= 4GB can be handled by IOMMU. Actually
+ * some IOMMUs can handle everything, but I don't know of a
+ * way to test this here.
+ */
+ if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
+ dma = 1;
+ q->limits.bounce_pfn = max(max_low_pfn, b_pfn);
+#else
+ if (b_pfn < blk_max_low_pfn)
+ dma = 1;
+ q->limits.bounce_pfn = b_pfn;
+#endif
+ if (dma) {
+ init_emergency_isa_pool();
+ q->bounce_gfp = GFP_NOIO | GFP_DMA;
+ q->limits.bounce_pfn = b_pfn;
+ }
+}
+EXPORT_SYMBOL(blk_queue_bounce_limit);
+
+/**
+ * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request
+ * @limits: the queue limits
+ * @max_hw_sectors: max hardware sectors in the usual 512b unit
+ *
+ * Description:
+ * Enables a low level driver to set a hard upper limit,
+ * max_hw_sectors, on the size of requests. max_hw_sectors is set by
+ * the device driver based upon the combined capabilities of I/O
+ * controller and storage device.
+ *
+ * max_sectors is a soft limit imposed by the block layer for
+ * filesystem type requests. This value can be overridden on a
+ * per-device basis in /sys/block/<device>/queue/max_sectors_kb.
+ * The soft limit can not exceed max_hw_sectors.
+ **/
+void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors)
+{
+ if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) {
+ max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
+ printk(KERN_INFO "%s: set to minimum %d\n",
+ __func__, max_hw_sectors);
+ }
+
+ limits->max_hw_sectors = max_hw_sectors;
+ limits->max_sectors = min_t(unsigned int, max_hw_sectors,
+ BLK_DEF_MAX_SECTORS);
+}
+EXPORT_SYMBOL(blk_limits_max_hw_sectors);
+
+/**
+ * blk_queue_max_hw_sectors - set max sectors for a request for this queue
+ * @q: the request queue for the device
+ * @max_hw_sectors: max hardware sectors in the usual 512b unit
+ *
+ * Description:
+ * See description for blk_limits_max_hw_sectors().
+ **/
+void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors)
+{
+ blk_limits_max_hw_sectors(&q->limits, max_hw_sectors);
+}
+EXPORT_SYMBOL(blk_queue_max_hw_sectors);
+
+/**
+ * blk_queue_max_discard_sectors - set max sectors for a single discard
+ * @q: the request queue for the device
+ * @max_discard_sectors: maximum number of sectors to discard
+ **/
+void blk_queue_max_discard_sectors(struct request_queue *q,
+ unsigned int max_discard_sectors)
+{
+ q->limits.max_discard_sectors = max_discard_sectors;
+}
+EXPORT_SYMBOL(blk_queue_max_discard_sectors);
+
+/**
+ * blk_queue_max_segments - set max hw segments for a request for this queue
+ * @q: the request queue for the device
+ * @max_segments: max number of segments
+ *
+ * Description:
+ * Enables a low level driver to set an upper limit on the number of
+ * hw data segments in a request.
+ **/
+void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments)
+{
+ if (!max_segments) {
+ max_segments = 1;
+ printk(KERN_INFO "%s: set to minimum %d\n",
+ __func__, max_segments);
+ }
+
+ q->limits.max_segments = max_segments;
+}
+EXPORT_SYMBOL(blk_queue_max_segments);
+
+/**
+ * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
+ * @q: the request queue for the device
+ * @max_size: max size of segment in bytes
+ *
+ * Description:
+ * Enables a low level driver to set an upper limit on the size of a
+ * coalesced segment
+ **/
+void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
+{
+ if (max_size < PAGE_CACHE_SIZE) {
+ max_size = PAGE_CACHE_SIZE;
+ printk(KERN_INFO "%s: set to minimum %d\n",
+ __func__, max_size);
+ }
+
+ q->limits.max_segment_size = max_size;
+}
+EXPORT_SYMBOL(blk_queue_max_segment_size);
+
+/**
+ * blk_queue_logical_block_size - set logical block size for the queue
+ * @q: the request queue for the device
+ * @size: the logical block size, in bytes
+ *
+ * Description:
+ * This should be set to the lowest possible block size that the
+ * storage device can address. The default of 512 covers most
+ * hardware.
+ **/
+void blk_queue_logical_block_size(struct request_queue *q, unsigned short size)
+{
+ q->limits.logical_block_size = size;
+
+ if (q->limits.physical_block_size < size)
+ q->limits.physical_block_size = size;
+
+ if (q->limits.io_min < q->limits.physical_block_size)
+ q->limits.io_min = q->limits.physical_block_size;
+}
+EXPORT_SYMBOL(blk_queue_logical_block_size);
+
+/**
+ * blk_queue_physical_block_size - set physical block size for the queue
+ * @q: the request queue for the device
+ * @size: the physical block size, in bytes
+ *
+ * Description:
+ * This should be set to the lowest possible sector size that the
+ * hardware can operate on without reverting to read-modify-write
+ * operations.
+ */
+void blk_queue_physical_block_size(struct request_queue *q, unsigned int size)
+{
+ q->limits.physical_block_size = size;
+
+ if (q->limits.physical_block_size < q->limits.logical_block_size)
+ q->limits.physical_block_size = q->limits.logical_block_size;
+
+ if (q->limits.io_min < q->limits.physical_block_size)
+ q->limits.io_min = q->limits.physical_block_size;
+}
+EXPORT_SYMBOL(blk_queue_physical_block_size);
+
+/**
+ * blk_queue_alignment_offset - set physical block alignment offset
+ * @q: the request queue for the device
+ * @offset: alignment offset in bytes
+ *
+ * Description:
+ * Some devices are naturally misaligned to compensate for things like
+ * the legacy DOS partition table 63-sector offset. Low-level drivers
+ * should call this function for devices whose first sector is not
+ * naturally aligned.
+ */
+void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset)
+{
+ q->limits.alignment_offset =
+ offset & (q->limits.physical_block_size - 1);
+ q->limits.misaligned = 0;
+}
+EXPORT_SYMBOL(blk_queue_alignment_offset);
+
+/**
+ * blk_limits_io_min - set minimum request size for a device
+ * @limits: the queue limits
+ * @min: smallest I/O size in bytes
+ *
+ * Description:
+ * Some devices have an internal block size bigger than the reported
+ * hardware sector size. This function can be used to signal the
+ * smallest I/O the device can perform without incurring a performance
+ * penalty.
+ */
+void blk_limits_io_min(struct queue_limits *limits, unsigned int min)
+{
+ limits->io_min = min;
+
+ if (limits->io_min < limits->logical_block_size)
+ limits->io_min = limits->logical_block_size;
+
+ if (limits->io_min < limits->physical_block_size)
+ limits->io_min = limits->physical_block_size;
+}
+EXPORT_SYMBOL(blk_limits_io_min);
+
+/**
+ * blk_queue_io_min - set minimum request size for the queue
+ * @q: the request queue for the device
+ * @min: smallest I/O size in bytes
+ *
+ * Description:
+ * Storage devices may report a granularity or preferred minimum I/O
+ * size which is the smallest request the device can perform without
+ * incurring a performance penalty. For disk drives this is often the
+ * physical block size. For RAID arrays it is often the stripe chunk
+ * size. A properly aligned multiple of minimum_io_size is the
+ * preferred request size for workloads where a high number of I/O
+ * operations is desired.
+ */
+void blk_queue_io_min(struct request_queue *q, unsigned int min)
+{
+ blk_limits_io_min(&q->limits, min);
+}
+EXPORT_SYMBOL(blk_queue_io_min);
+
+/**
+ * blk_limits_io_opt - set optimal request size for a device
+ * @limits: the queue limits
+ * @opt: smallest I/O size in bytes
+ *
+ * Description:
+ * Storage devices may report an optimal I/O size, which is the
+ * device's preferred unit for sustained I/O. This is rarely reported
+ * for disk drives. For RAID arrays it is usually the stripe width or
+ * the internal track size. A properly aligned multiple of
+ * optimal_io_size is the preferred request size for workloads where
+ * sustained throughput is desired.
+ */
+void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt)
+{
+ limits->io_opt = opt;
+}
+EXPORT_SYMBOL(blk_limits_io_opt);
+
+/**
+ * blk_queue_io_opt - set optimal request size for the queue
+ * @q: the request queue for the device
+ * @opt: optimal request size in bytes
+ *
+ * Description:
+ * Storage devices may report an optimal I/O size, which is the
+ * device's preferred unit for sustained I/O. This is rarely reported
+ * for disk drives. For RAID arrays it is usually the stripe width or
+ * the internal track size. A properly aligned multiple of
+ * optimal_io_size is the preferred request size for workloads where
+ * sustained throughput is desired.
+ */
+void blk_queue_io_opt(struct request_queue *q, unsigned int opt)
+{
+ blk_limits_io_opt(&q->limits, opt);
+}
+EXPORT_SYMBOL(blk_queue_io_opt);
+
+/**
+ * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
+ * @t: the stacking driver (top)
+ * @b: the underlying device (bottom)
+ **/
+void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
+{
+ blk_stack_limits(&t->limits, &b->limits, 0);
+}
+EXPORT_SYMBOL(blk_queue_stack_limits);
+
+/**
+ * blk_stack_limits - adjust queue_limits for stacked devices
+ * @t: the stacking driver limits (top device)
+ * @b: the underlying queue limits (bottom, component device)
+ * @start: first data sector within component device
+ *
+ * Description:
+ * This function is used by stacking drivers like MD and DM to ensure
+ * that all component devices have compatible block sizes and
+ * alignments. The stacking driver must provide a queue_limits
+ * struct (top) and then iteratively call the stacking function for
+ * all component (bottom) devices. The stacking function will
+ * attempt to combine the values and ensure proper alignment.
+ *
+ * Returns 0 if the top and bottom queue_limits are compatible. The
+ * top device's block sizes and alignment offsets may be adjusted to
+ * ensure alignment with the bottom device. If no compatible sizes
+ * and alignments exist, -1 is returned and the resulting top
+ * queue_limits will have the misaligned flag set to indicate that
+ * the alignment_offset is undefined.
+ */
+int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
+ sector_t start)
+{
+ unsigned int top, bottom, alignment, ret = 0;
+
+ t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors);
+ t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors);
+ t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn);
+
+ t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask,
+ b->seg_boundary_mask);
+
+ t->max_segments = min_not_zero(t->max_segments, b->max_segments);
+ t->max_integrity_segments = min_not_zero(t->max_integrity_segments,
+ b->max_integrity_segments);
+
+ t->max_segment_size = min_not_zero(t->max_segment_size,
+ b->max_segment_size);
+
+ t->misaligned |= b->misaligned;
+
+ alignment = queue_limit_alignment_offset(b, start);
+
+ /* Bottom device has different alignment. Check that it is
+ * compatible with the current top alignment.
+ */
+ if (t->alignment_offset != alignment) {
+
+ top = max(t->physical_block_size, t->io_min)
+ + t->alignment_offset;
+ bottom = max(b->physical_block_size, b->io_min) + alignment;
+
+ /* Verify that top and bottom intervals line up */
+ if (max(top, bottom) % min(top, bottom)) {
+ t->misaligned = 1;
+ ret = -1;
+ }
+ }
+
+ t->logical_block_size = max(t->logical_block_size,
+ b->logical_block_size);
+
+ t->physical_block_size = max(t->physical_block_size,
+ b->physical_block_size);
+
+ t->io_min = max(t->io_min, b->io_min);
+ t->io_opt = lcm(t->io_opt, b->io_opt);
+
+ t->cluster &= b->cluster;
+ t->discard_zeroes_data &= b->discard_zeroes_data;
+
+ /* Physical block size a multiple of the logical block size? */
+ if (t->physical_block_size & (t->logical_block_size - 1)) {
+ t->physical_block_size = t->logical_block_size;
+ t->misaligned = 1;
+ ret = -1;
+ }
+
+ /* Minimum I/O a multiple of the physical block size? */
+ if (t->io_min & (t->physical_block_size - 1)) {
+ t->io_min = t->physical_block_size;
+ t->misaligned = 1;
+ ret = -1;
+ }
+
+ /* Optimal I/O a multiple of the physical block size? */
+ if (t->io_opt & (t->physical_block_size - 1)) {
+ t->io_opt = 0;
+ t->misaligned = 1;
+ ret = -1;
+ }
+
+ /* Find lowest common alignment_offset */
+ t->alignment_offset = lcm(t->alignment_offset, alignment)
+ % max(t->physical_block_size, t->io_min);
+
+ /* Verify that new alignment_offset is on a logical block boundary */
+ if (t->alignment_offset & (t->logical_block_size - 1)) {
+ t->misaligned = 1;
+ ret = -1;
+ }
+
+ /* Discard alignment and granularity */
+ if (b->discard_granularity) {
+ alignment = queue_limit_discard_alignment(b, start);
+
+ if (t->discard_granularity != 0 &&
+ t->discard_alignment != alignment) {
+ top = t->discard_granularity + t->discard_alignment;
+ bottom = b->discard_granularity + alignment;
+
+ /* Verify that top and bottom intervals line up */
+ if (max(top, bottom) & (min(top, bottom) - 1))
+ t->discard_misaligned = 1;
+ }
+
+ t->max_discard_sectors = min_not_zero(t->max_discard_sectors,
+ b->max_discard_sectors);
+ t->discard_granularity = max(t->discard_granularity,
+ b->discard_granularity);
+ t->discard_alignment = lcm(t->discard_alignment, alignment) &
+ (t->discard_granularity - 1);
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL(blk_stack_limits);
+
+/**
+ * bdev_stack_limits - adjust queue limits for stacked drivers
+ * @t: the stacking driver limits (top device)
+ * @bdev: the component block_device (bottom)
+ * @start: first data sector within component device
+ *
+ * Description:
+ * Merges queue limits for a top device and a block_device. Returns
+ * 0 if alignment didn't change. Returns -1 if adding the bottom
+ * device caused misalignment.
+ */
+int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
+ sector_t start)
+{
+ struct request_queue *bq = bdev_get_queue(bdev);
+
+ start += get_start_sect(bdev);
+
+ return blk_stack_limits(t, &bq->limits, start);
+}
+EXPORT_SYMBOL(bdev_stack_limits);
+
+/**
+ * disk_stack_limits - adjust queue limits for stacked drivers
+ * @disk: MD/DM gendisk (top)
+ * @bdev: the underlying block device (bottom)
+ * @offset: offset to beginning of data within component device
+ *
+ * Description:
+ * Merges the limits for a top level gendisk and a bottom level
+ * block_device.
+ */
+void disk_stack_limits(struct gendisk *disk, struct block_device *bdev,
+ sector_t offset)
+{
+ struct request_queue *t = disk->queue;
+
+ if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) {
+ char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE];
+
+ disk_name(disk, 0, top);
+ bdevname(bdev, bottom);
+
+ printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n",
+ top, bottom);
+ }
+}
+EXPORT_SYMBOL(disk_stack_limits);
+
+/**
+ * blk_queue_dma_pad - set pad mask
+ * @q: the request queue for the device
+ * @mask: pad mask
+ *
+ * Set dma pad mask.
+ *
+ * Appending pad buffer to a request modifies the last entry of a
+ * scatter list such that it includes the pad buffer.
+ **/
+void blk_queue_dma_pad(struct request_queue *q, unsigned int mask)
+{
+ q->dma_pad_mask = mask;
+}
+EXPORT_SYMBOL(blk_queue_dma_pad);
+
+/**
+ * blk_queue_update_dma_pad - update pad mask
+ * @q: the request queue for the device
+ * @mask: pad mask
+ *
+ * Update dma pad mask.
+ *
+ * Appending pad buffer to a request modifies the last entry of a
+ * scatter list such that it includes the pad buffer.
+ **/
+void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask)
+{
+ if (mask > q->dma_pad_mask)
+ q->dma_pad_mask = mask;
+}
+EXPORT_SYMBOL(blk_queue_update_dma_pad);
+
+/**
+ * blk_queue_dma_drain - Set up a drain buffer for excess dma.
+ * @q: the request queue for the device
+ * @dma_drain_needed: fn which returns non-zero if drain is necessary
+ * @buf: physically contiguous buffer
+ * @size: size of the buffer in bytes
+ *
+ * Some devices have excess DMA problems and can't simply discard (or
+ * zero fill) the unwanted piece of the transfer. They have to have a
+ * real area of memory to transfer it into. The use case for this is
+ * ATAPI devices in DMA mode. If the packet command causes a transfer
+ * bigger than the transfer size some HBAs will lock up if there
+ * aren't DMA elements to contain the excess transfer. What this API
+ * does is adjust the queue so that the buf is always appended
+ * silently to the scatterlist.
+ *
+ * Note: This routine adjusts max_hw_segments to make room for appending
+ * the drain buffer. If you call blk_queue_max_segments() after calling
+ * this routine, you must set the limit to one fewer than your device
+ * can support otherwise there won't be room for the drain buffer.
+ */
+int blk_queue_dma_drain(struct request_queue *q,
+ dma_drain_needed_fn *dma_drain_needed,
+ void *buf, unsigned int size)
+{
+ if (queue_max_segments(q) < 2)
+ return -EINVAL;
+ /* make room for appending the drain */
+ blk_queue_max_segments(q, queue_max_segments(q) - 1);
+ q->dma_drain_needed = dma_drain_needed;
+ q->dma_drain_buffer = buf;
+ q->dma_drain_size = size;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
+
+/**
+ * blk_queue_segment_boundary - set boundary rules for segment merging
+ * @q: the request queue for the device
+ * @mask: the memory boundary mask
+ **/
+void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
+{
+ if (mask < PAGE_CACHE_SIZE - 1) {
+ mask = PAGE_CACHE_SIZE - 1;
+ printk(KERN_INFO "%s: set to minimum %lx\n",
+ __func__, mask);
+ }
+
+ q->limits.seg_boundary_mask = mask;
+}
+EXPORT_SYMBOL(blk_queue_segment_boundary);
+
+/**
+ * blk_queue_dma_alignment - set dma length and memory alignment
+ * @q: the request queue for the device
+ * @mask: alignment mask
+ *
+ * description:
+ * set required memory and length alignment for direct dma transactions.
+ * this is used when building direct io requests for the queue.
+ *
+ **/
+void blk_queue_dma_alignment(struct request_queue *q, int mask)
+{
+ q->dma_alignment = mask;
+}
+EXPORT_SYMBOL(blk_queue_dma_alignment);
+
+/**
+ * blk_queue_update_dma_alignment - update dma length and memory alignment
+ * @q: the request queue for the device
+ * @mask: alignment mask
+ *
+ * description:
+ * update required memory and length alignment for direct dma transactions.
+ * If the requested alignment is larger than the current alignment, then
+ * the current queue alignment is updated to the new value, otherwise it
+ * is left alone. The design of this is to allow multiple objects
+ * (driver, device, transport etc) to set their respective
+ * alignments without having them interfere.
+ *
+ **/
+void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
+{
+ BUG_ON(mask > PAGE_SIZE);
+
+ if (mask > q->dma_alignment)
+ q->dma_alignment = mask;
+}
+EXPORT_SYMBOL(blk_queue_update_dma_alignment);
+
+/**
+ * blk_queue_flush - configure queue's cache flush capability
+ * @q: the request queue for the device
+ * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA
+ *
+ * Tell block layer cache flush capability of @q. If it supports
+ * flushing, REQ_FLUSH should be set. If it supports bypassing
+ * write cache for individual writes, REQ_FUA should be set.
+ */
+void blk_queue_flush(struct request_queue *q, unsigned int flush)
+{
+ WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA));
+
+ if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA)))
+ flush &= ~REQ_FUA;
+
+ q->flush_flags = flush & (REQ_FLUSH | REQ_FUA);
+}
+EXPORT_SYMBOL_GPL(blk_queue_flush);
+
+void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
+{
+ q->flush_not_queueable = !queueable;
+}
+EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
+
+static int __init blk_settings_init(void)
+{
+ blk_max_low_pfn = max_low_pfn - 1;
+ blk_max_pfn = max_pfn - 1;
+ return 0;
+}
+subsys_initcall(blk_settings_init);