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authorChristoph Hellwig <hch@lst.de>2017-04-05 19:21:10 +0200
committerJens Axboe <axboe@fb.com>2017-04-08 11:25:38 -0600
commitcb365b9675fda026caba4cb5df83292cb7c0811a (patch)
treefbb1e83537ed759ae63b5e1dc93f741acb30d552
parentd928be9f853b9755692d7e9aed402c1809a88e56 (diff)
block: add a new BLKDEV_ZERO_NOFALLBACK flag
This avoids fallbacks to explicit zeroing in (__)blkdev_issue_zeroout if the caller doesn't want them. Also clean up the convoluted check for the return condition that this new flag is added to. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--block/blk-lib.c5
-rw-r--r--include/linux/blkdev.h1
2 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-lib.c b/block/blk-lib.c
index 2f6d2cb2e1a2..2f882e22890b 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -281,6 +281,9 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
*
* If a device is using logical block provisioning, the underlying space will
* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
+ *
+ * If %flags contains BLKDEV_ZERO_NOFALLBACK, the function will return
+ * -EOPNOTSUPP if no explicit hardware offload for zeroing is provided.
*/
int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,
@@ -298,7 +301,7 @@ int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
ret = __blkdev_issue_write_zeroes(bdev, sector, nr_sects, gfp_mask,
biop, flags);
- if (ret == 0 || (ret && ret != -EOPNOTSUPP))
+ if (ret != -EOPNOTSUPP || (flags & BLKDEV_ZERO_NOFALLBACK))
goto out;
ret = 0;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index bd60f4401c9d..21a30f011674 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1350,6 +1350,7 @@ extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
struct bio **biop);
#define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */
+#define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */
extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct bio **biop,