On Mon, Aug 3, 2015 at 10:28 AM, Mike Snitzer <[email protected]> wrote: > On Sun, Aug 02 2015 at 10:01P -0400, > Josh Boyer <[email protected]> wrote: > >> On Fri, Jul 31, 2015 at 2:58 PM, Josh Boyer <[email protected]> >> wrote: >> > On Thu, Jul 30, 2015 at 8:19 PM, Mike Snitzer <[email protected]> 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)?
Sure, I'll get a kernel with this included spun up and ask Adam to test. josh > From: Mike Snitzer <[email protected]> > 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 <[email protected]> > Acked-by: Joe Thornber <[email protected]> > Signed-off-by: Mike Snitzer <[email protected]> > Cc: [email protected] # 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 [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
