From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Christoph Hellwig To: axboe@kernel.dk, martin.petersen@oracle.com, agk@redhat.com, snitzer@redhat.com, shli@kernel.org, philipp.reisner@linbit.com, lars.ellenberg@linbit.com Cc: linux-block@vger.kernel.org, linux-scsi@vger.kernel.org, drbd-dev@lists.linbit.com, dm-devel@redhat.com, linux-raid@vger.kernel.org Subject: [PATCH 22/25] block: stop using discards for zeroing Date: Fri, 31 Mar 2017 18:33:10 +0200 Message-Id: <20170331163313.31821-23-hch@lst.de> In-Reply-To: <20170331163313.31821-1-hch@lst.de> References: <20170331163313.31821-1-hch@lst.de> List-ID: Now that we have REQ_OP_WRITE_ZEROES implemented for all devices that support efficient zeroing of devices we can remove the call to blkdev_issue_discard. This means we only have two ways of zeroing left and can simply the code. Signed-off-by: Christoph Hellwig --- block/blk-lib.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/block/blk-lib.c b/block/blk-lib.c index 2f882e22890b..7c27211570fa 100644 --- a/block/blk-lib.c +++ b/block/blk-lib.c @@ -279,6 +279,11 @@ 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 supports + * efficient zeroing operation, but the device capabilities can only be + * discovered by trial and error. In this case the caller should call the + * function again, and it will use the fallback path. + * * If a device is using logical block provisioning, the underlying space will * not be released if %flags contains BLKDEV_ZERO_NOUNMAP. * @@ -349,12 +354,6 @@ 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); -- 2.11.0