From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: To: Christoph Hellwig Cc: axboe@kernel.dk, martin.petersen@oracle.com, agk@redhat.com, snitzer@redhat.com, shli@kernel.org, philipp.reisner@linbit.com, lars.ellenberg@linbit.com, 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: Re: [PATCH 22/25] block: stop using discards for zeroing From: "Martin K. Petersen" References: <20170331163313.31821-1-hch@lst.de> <20170331163313.31821-23-hch@lst.de> Date: Wed, 05 Apr 2017 07:55:39 -0400 In-Reply-To: <20170331163313.31821-23-hch@lst.de> (Christoph Hellwig's message of "Fri, 31 Mar 2017 18:33:10 +0200") Message-ID: MIME-Version: 1.0 Content-Type: text/plain List-ID: Christoph Hellwig writes: > Now that we have REQ_OP_WRITE_ZEROES implemented for all devices that > support efficient zeroing of devices we can remove the call to s/of devices/ > blkdev_issue_discard. This means we only have two ways of zeroing > left and can simply the code. simplify > + * 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. Maybe: "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). If -EOPNOTSUPP is returned, the caller should retry the blkdev_issue_zeroout() and the fallback path will be used." Otherwise OK. Reviewed-by: Martin K. Petersen -- Martin K. Petersen Oracle Linux Engineering