On Sun, Aug 02 2015 at 10:01P -0400, Josh Boyer <jwbo...@fedoraproject.org> wrote:
> On Fri, Jul 31, 2015 at 2:58 PM, Josh Boyer <jwbo...@fedoraproject.org> wrote: > > On Thu, Jul 30, 2015 at 8:19 PM, Mike Snitzer <snit...@redhat.com> wrote: > >> > >> The only commit that looks even remotely related (given 32bit concerns) > >> would be 1c220c69ce0dcc0f234a9f263ad9c0864f971852 > > > > Confirmed. I built kernels for our tester that started with the > > working snapshot and applied the patches above one at a time. The > > failing patch was the commit you suspected. > > > > I can try and build a 4.2-rc4 kernel with that reverted, but it would > > be good if someone could start thinking about how that could cause > > this issue. > > A revert on top of 4.2-rc4 booted. So this is currently causing > issues with upstream as well. Hi Josh, I've staged the following fix in linux-next (for 4.2-rc6 inclusion): https://git.kernel.org/cgit/linux/kernel/git/device-mapper/linux-dm.git/commit/?h=for-next&id=76270d574acc897178a5c8be0bd2a743a77e4bac Can you please verify that it works for your 32bit testcase against 4.2-rc4 (or rc5)? Thanks. From: Mike Snitzer <snit...@redhat.com> Date: Mon, 3 Aug 2015 09:54:58 -0400 Subject: [PATCH] dm: fix dm_merge_bvec regression on 32 bit systems A DM regression on 32 bit systems was reported against v4.2-rc3 here: https://lkml.org/lkml/2015/7/29/401 Fix this by reverting both commit 1c220c69 ("dm: fix casting bug in dm_merge_bvec()") and 148e51ba ("dm: improve documentation and code clarity in dm_merge_bvec"). This combined revert is done to eliminate the possibility of a partial revert in stable@ kernels. In hindsight the correct fix, at the time 1c220c69 was applied to fix the regression that 148e51ba introduced, should've been to simply revert 148e51ba. Reported-by: Josh Boyer <jwbo...@fedoraproject.org> Acked-by: Joe Thornber <e...@redhat.com> Signed-off-by: Mike Snitzer <snit...@redhat.com> Cc: sta...@vger.kernel.org # 3.19+ --- drivers/md/dm.c | 27 ++++++++++----------------- 1 file changed, 10 insertions(+), 17 deletions(-) diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ab37ae1..0d7ab20 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1729,7 +1729,8 @@ static int dm_merge_bvec(struct request_queue *q, struct mapped_device *md = q->queuedata; struct dm_table *map = dm_get_live_table_fast(md); struct dm_target *ti; - sector_t max_sectors, max_size = 0; + sector_t max_sectors; + int max_size = 0; if (unlikely(!map)) goto out; @@ -1742,18 +1743,10 @@ static int dm_merge_bvec(struct request_queue *q, * Find maximum amount of I/O that won't need splitting */ max_sectors = min(max_io_len(bvm->bi_sector, ti), - (sector_t) queue_max_sectors(q)); + (sector_t) BIO_MAX_SECTORS); max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; - - /* - * FIXME: this stop-gap fix _must_ be cleaned up (by passing a sector_t - * to the targets' merge function since it holds sectors not bytes). - * Just doing this as an interim fix for stable@ because the more - * comprehensive cleanup of switching to sector_t will impact every - * DM target that implements a ->merge hook. - */ - if (max_size > INT_MAX) - max_size = INT_MAX; + if (max_size < 0) + max_size = 0; /* * merge_bvec_fn() returns number of bytes @@ -1761,13 +1754,13 @@ static int dm_merge_bvec(struct request_queue *q, * max is precomputed maximal io size */ if (max_size && ti->type->merge) - max_size = ti->type->merge(ti, bvm, biovec, (int) max_size); + max_size = ti->type->merge(ti, bvm, biovec, max_size); /* * If the target doesn't support merge method and some of the devices - * provided their merge_bvec method (we know this by looking for the - * max_hw_sectors that dm_set_device_limits may set), then we can't - * allow bios with multiple vector entries. So always set max_size - * to 0, and the code below allows just one page. + * provided their merge_bvec method (we know this by looking at + * queue_max_hw_sectors), then we can't allow bios with multiple vector + * entries. So always set max_size to 0, and the code below allows + * just one page. */ else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9) max_size = 0; -- 2.3.2 (Apple Git-55) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
