From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: To: James Bottomley Cc: "martin.petersen\@oracle.com" , "linux-kernel\@vger.kernel.org" , "hch\@infradead.org" , "devel\@linuxdriverproject.org" , "apw\@canonical.com" , "kys\@microsoft.com" , "stable\@vger.kernel.org" , "linux-scsi\@vger.kernel.org" , "ohering\@suse.com" , "jasowang\@redhat.com" Subject: Re: [PATCH 4/8] Drivers: scsi: storvsc: Filter WRITE_SAME_16 From: "Martin K. Petersen" References: <20140709084300.GD6012@infradead.org> <1404935792.2184.5.camel@dabdike.int.hansenpartnership.com> <2f3ae589e6f149acbe4c5dd79f905971@BY2PR03MB299.namprd03.prod.outlook.com> <1404944843.2184.8.camel@dabdike.int.hansenpartnership.com> <20140711063216.GA20660@infradead.org> <328b7a6174ef4dd8a54a7db5ac959834@BY2PR03MB299.namprd03.prod.outlook.com> <20140716110111.GA7382@infradead.org> <20140716173827.GB20528@infradead.org> <1405533734.3165.12.camel@dabdike.int.hansenpartnership.com> Date: Wed, 16 Jul 2014 14:45:46 -0400 In-Reply-To: <1405533734.3165.12.camel@dabdike.int.hansenpartnership.com> (James Bottomley's message of "Wed, 16 Jul 2014 18:02:14 +0000") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: >>>>> "James" == James Bottomley writes: >> I don't have a problem with a BLIST_PREFER_UNMAP flag or something >> like that. But BLIST_TRY_VPD_PAGES seems more generally useful and it >> does fix the problem at hand. That's why I went that route. James> Hang on ... unless we apply Christoph or my fix, we'll get the James> same issue with every raid driver (that's about 10 I think) that James> set no_write_same when they hit a >2TB RAID volume, no_write_same is set for all the RAID controller drivers (54b2b50c20a6). If a WRITE SAME(10/16) command fails and the UNMAP bit is not set we'll set no_write_same=1 and disable REQ_WRITE_SAME support. If a WRITE SAME(10/16) command fails and the UNMAP bit is set we'll disable REQ_DISCARD support. Not sure where the 10 vs. 16 byte 2TB limitation comes into play here? -- Martin K. Petersen Oracle Linux Engineering