diff options
| author | Mike Snitzer <snitzer@redhat.com> | 2015-08-03 09:54:58 -0400 |
|---|---|---|
| committer | Mike Snitzer <snitzer@redhat.com> | 2015-08-03 22:49:59 -0400 |
| commit | bd4aaf8f9b85d6b2df3231fd62b219ebb75d3568 (patch) | |
| tree | 00b52bacf20f8c239e0edbbac3b8047f98c0bb0e /drivers/md/dm.c | |
| parent | 795e633a2dc6cbbeac68bc7f6006082150d38bb7 (diff) | |
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 <jwboyer@fedoraproject.org>
Tested-by: Adam Williamson <awilliam@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 3.19+
Diffstat (limited to 'drivers/md/dm.c')
| -rw-r--r-- | drivers/md/dm.c | 27 |
1 files changed, 10 insertions, 17 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index ab37ae114e94..0d7ab20c58df 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; |