From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 3/7] block: Make blkdev_issue_zeroout use WRITE SAME Date: Fri, 09 Mar 2012 19:05:49 +0100 Message-ID: <4F5A467D.1000703@redhat.com> References: <1330658571-12958-1-git-send-email-martin.petersen@oracle.com> <1330658571-12958-4-git-send-email-martin.petersen@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pz0-f46.google.com ([209.85.210.46]:46002 "EHLO mail-pz0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754296Ab2CISF4 (ORCPT ); Fri, 9 Mar 2012 13:05:56 -0500 Received: by dajr28 with SMTP id r28so1698711daj.19 for ; Fri, 09 Mar 2012 10:05:56 -0800 (PST) In-Reply-To: <1330658571-12958-4-git-send-email-martin.petersen@oracle.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Martin K. Petersen" Cc: jaxboe@fusionio.com, James.Bottomley@hansenpartnership.com, snitzer@redhat.com, vgoyal@redhat.com, michaelc@cs.wisc.edu, linux-scsi@vger.kernel.org Il 02/03/2012 04:22, Martin K. Petersen ha scritto: > +int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, > + sector_t nr_sects, gfp_t gfp_mask) > +{ > + if (bdev_write_same(bdev)) { > + unsigned char bdn[BDEVNAME_SIZE]; > + > + if (!blkdev_issue_write_same(bdev, sector, nr_sects, gfp_mask, > + ZERO_PAGE(0))) > + return 0; > + > + bdevname(bdev, bdn); > + printk(KERN_ERR "%s: WRITE SAME failed. Manually zeroing.\n", > + bdn); > + } > + > + return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask); > +} Why not try DISCARD first if lbprz is true and the alignment is okay? This doesn't even require WRITE SAME support in the disk. Paolo