From b49a0871be31a745b2ef7912653683a1876ff701 Mon Sep 17 00:00:00 2001 From: Ming Lin Date: Fri, 22 May 2015 00:46:56 -0700 Subject: [PATCH] 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 Signed-off-by: Ming Lin Signed-off-by: Jens Axboe --- block/blk-lib.c | 47 +++++++++++------------------------------------ 1 file 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;