From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mike Snitzer Subject: Re: block: use kmalloc alignment for bio slab Date: Mon, 7 Apr 2014 14:15:50 -0400 Message-ID: <20140407181550.GA30132@redhat.com> References: <1396461856-27243-1-git-send-email-snitzer@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1396461856-27243-1-git-send-email-snitzer@redhat.com> Sender: linux-kernel-owner@vger.kernel.org To: axboe@fb.com Cc: dm-devel@redhat.com, mpatocka@redhat.com, linux-kernel@vger.kernel.org List-Id: dm-devel.ids On Wed, Apr 02 2014 at 2:04pm -0400, Mike Snitzer wrote: > From: Mikulas Patocka > > Various subsystems can ask the bio subsystem to create a bio slab cache > with some free space before the bio. This free space can be used for any > purpose. Device mapper uses this per-bio-data feature to place some > target-specific and device-mapper specific data before the bio, so that > the target-specific data doesn't have to be allocated separately. > > This per-bio-data mechanism is used in place of kmalloc, so we need the > allocated slab to have the same memory alignment as memory allocated > with kmalloc. > > Change bio_find_or_create_slab() so that it uses ARCH_KMALLOC_MINALIGN > alignment when creating the slab cache. This is needed so that dm-crypt > can use per-bio-data for encryption - the crypto subsystem assumes this > data will have the same alignment as kmalloc'ed memory. > > Signed-off-by: Mikulas Patocka > Signed-off-by: Mike Snitzer Hey Jens, Just wanted to give you a heads up that I staged this patch in linux-dm.git's 'for-next', here: https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=for-next&id=cd433c25f43eb054f62b7b48f1d0349f65b1740c I rebased it to add this yesterday: Acked-by: Jens Axboe # via private exchange on facebook I put this in place because there is a chance I'll still be sending the improved dm-crypt parallelization patches to Linus for 3.15 this week. So having this go through linux-dm.git saves the awkward coordination where otherwise DM would be depending on the block tree. You OK with this?