block: stop using discards for zeroing

Now that we have REQ_OP_WRITE_ZEROES implemented for all devices that
support efficient zeroing, we can remove the call to blkdev_issue_discard.
This means we only have two ways of zeroing left and can simplify the
code.

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>
This commit is contained in:
Christoph Hellwig 2017-04-05 19:21:20 +02:00 committed by Jens Axboe
parent 5d1429fead
commit 71027e97d7

View file

@ -279,6 +279,12 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
* Zero-fill a block range, either using hardware offload or by explicitly
* writing zeroes to the device.
*
* Note that this function may fail with -EOPNOTSUPP if the driver signals
* zeroing offload support, but the device fails to process the command (for
* some devices there is no non-destructive way to verify whether this
* operation is actually supported). In this case the caller should call
* retry the call to blkdev_issue_zeroout() and the fallback path will be used.
*
* If a device is using logical block provisioning, the underlying space will
* not be released if %flags contains BLKDEV_ZERO_NOUNMAP.
*
@ -349,12 +355,6 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
struct bio *bio = NULL;
struct blk_plug plug;
if (!(flags & BLKDEV_ZERO_NOUNMAP)) {
if (!blkdev_issue_discard(bdev, sector, nr_sects, gfp_mask,
BLKDEV_DISCARD_ZERO))
return 0;
}
blk_start_plug(&plug);
ret = __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask,
&bio, flags);