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authorMing Lin <ming.l@ssi.samsung.com>2015-05-22 00:46:56 -0700
committerJens Axboe <axboe@fb.com>2015-08-13 12:31:47 -0600
commitb49a0871be31a745b2ef7912653683a1876ff701 (patch)
tree6fd3b77faea6f585e9ad9a781c0c348d49242f10 /block/blk-lib.c
parent0e28997ec476bad4c7dbe0a08775290051325f53 (diff)
downloadlinux-linaro-stable-b49a0871be31a745b2ef7912653683a1876ff701.tar.gz
block: remove split code in blkdev_issue_{discard,write_same}
The split code in blkdev_issue_{discard,write_same} can go away now that any driver that cares does the split. We have to make sure bio size doesn't overflow. For discard, we set max discard sectors to (1<<31)>>9 to ensure it doesn't overflow bi_size and hopefully it is of the proper granularity as long as the granularity is a power of two. Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Ming Lin <ming.l@ssi.samsung.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-lib.c')
-rw-r--r--block/blk-lib.c47
1 files changed, 11 insertions, 36 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 6dee17443f14..bd40292e5009 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -26,6 +26,13 @@ static void bio_batch_end_io(struct bio *bio)
bio_put(bio);
}
+/*
+ * Ensure that max discard sectors doesn't overflow bi_size and hopefully
+ * it is of the proper granularity as long as the granularity is a power
+ * of two.
+ */
+#define MAX_BIO_SECTORS ((1U << 31) >> 9)
+
/**
* blkdev_issue_discard - queue a discard
* @bdev: blockdev to issue discard for
@@ -43,8 +50,6 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
DECLARE_COMPLETION_ONSTACK(wait);
struct request_queue *q = bdev_get_queue(bdev);
int type = REQ_WRITE | REQ_DISCARD;
- unsigned int max_discard_sectors, granularity;
- int alignment;
struct bio_batch bb;
struct bio *bio;
int ret = 0;
@@ -56,21 +61,6 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
if (!blk_queue_discard(q))
return -EOPNOTSUPP;
- /* Zero-sector (unknown) and one-sector granularities are the same. */
- granularity = max(q->limits.discard_granularity >> 9, 1U);
- alignment = (bdev_discard_alignment(bdev) >> 9) % granularity;
-
- /*
- * Ensure that max_discard_sectors is of the proper
- * granularity, so that requests stay aligned after a split.
- */
- max_discard_sectors = min(q->limits.max_discard_sectors, UINT_MAX >> 9);
- max_discard_sectors -= max_discard_sectors % granularity;
- if (unlikely(!max_discard_sectors)) {
- /* Avoid infinite loop below. Being cautious never hurts. */
- return -EOPNOTSUPP;
- }
-
if (flags & BLKDEV_DISCARD_SECURE) {
if (!blk_queue_secdiscard(q))
return -EOPNOTSUPP;
@@ -84,7 +74,7 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
blk_start_plug(&plug);
while (nr_sects) {
unsigned int req_sects;
- sector_t end_sect, tmp;
+ sector_t end_sect;
bio = bio_alloc(gfp_mask, 1);
if (!bio) {
@@ -92,21 +82,8 @@ int blkdev_issue_discard(struct block_device *bdev, sector_t sector,
break;
}
- req_sects = min_t(sector_t, nr_sects, max_discard_sectors);
-
- /*
- * If splitting a request, and the next starting sector would be
- * misaligned, stop the discard at the previous aligned sector.
- */
+ req_sects = min_t(sector_t, nr_sects, MAX_BIO_SECTORS);
end_sect = sector + req_sects;
- tmp = end_sect;
- if (req_sects < nr_sects &&
- sector_div(tmp, granularity) != alignment) {
- end_sect = end_sect - alignment;
- sector_div(end_sect, granularity);
- end_sect = end_sect * granularity + alignment;
- req_sects = end_sect - sector;
- }
bio->bi_iter.bi_sector = sector;
bio->bi_end_io = bio_batch_end_io;
@@ -165,10 +142,8 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
if (!q)
return -ENXIO;
- max_write_same_sectors = q->limits.max_write_same_sectors;
-
- if (max_write_same_sectors == 0)
- return -EOPNOTSUPP;
+ /* Ensure that max_write_same_sectors doesn't overflow bi_size */
+ max_write_same_sectors = UINT_MAX >> 9;
atomic_set(&bb.done, 1);
bb.error = 0;