On Tue, Oct 30, 2007 at 01:11:38PM -0700, Andrew Morton wrote: > On Mon, 29 Oct 2007 09:31:39 +0300 > Vasily Averin <vvs@xxxxx> wrote: > > Device mapper uses its own bounce_pfn that may differ from one on underlying > > device. In that way dm can build incorrect requests that contain sg elements > > greater than underlying device is able to handle. > > This is the cause of slab corruption in i2o layer, occurred on i386 arch when > > very long direct IO requests are addressed to dm-over-i2o device. Interesting. When this patch was originally proposed a couple of years ago, we did this instead: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=daef265f1590cf3e6de989d074041a280c82d58b;hp=00d6da9b4d6707b808481372537adb0fb38f99b3 ) DM doesn't need to bounce bio's on its own, but the block layer defaults ) to that in blk_queue_make_request(). The lower level drivers should ) bounce ios themselves, that is what they need to do if not layered below ) dm anyways. Alasdair -- agk@xxxxxxxxxx -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
