From mboxrd@z Thu Jan 1 00:00:00 1970 From: snitzer@redhat.com (Mike Snitzer) Date: Wed, 21 Oct 2015 11:33:51 -0400 Subject: [PATCH v6 05/11] block: remove split code in blkdev_issue_{discard,write_same} In-Reply-To: <1445439679.3126.5.camel@hasee> References: <1439363241-31772-1-git-send-email-mlin@kernel.org> <1439363241-31772-6-git-send-email-mlin@kernel.org> <20151013115011.GA6546@infradead.org> <20151021072126.GA7671@infradead.org> <1445439679.3126.5.camel@hasee> Message-ID: <20151021153351.GA4984@redhat.com> On Wed, Oct 21 2015 at 11:01am -0400, Ming Lin wrote: > On Wed, 2015-10-21@09:39 -0400, Jeff Moyer wrote: > > Christoph Hellwig writes: > > > > > Jens, Ming: > > > > > > are you fine with the one liner change to get back to the old I/O > > > pattern? While it looks like the cards fault I'd like to avoid this > > > annoying regression. > > > > I'm not Jens or Ming, but your patch looks fine to me, though you'll > > want to remove the MAX_BIO_SECTORS definition since it's now unused. > > It's not clear to me why the limit was lowered in the first place. > > UINT_MAX >> 9 is not power of 2 and it causes dm-thinp discard fails. > > At the lengthy discussion: > [PATCH v5 01/11] block: make generic_make_request handle arbitrarily sized bios > We agreed to cap discard to 2G as an interim solution for 4.3 until the > dm-thinp discard code is rewritten. But did Jens ever commit that change to cap at 2G? I don't recall seeing it. > Hi Mike, > > Will the dm-thinp discard rewritten ready for 4.4? No. I'm not clear what needs changing in dm-thinp. I'll have to revisit the thread to refresh my memory. BTW, DM thinp can easily handle discards that aren't a power-of-2 so long as the requested discard is a factor of the thinp blocksize.