Merge tag 'for-5.2/dm-fix-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fix from Mike Snitzer:
 "Fix a particularly glaring oversight in a DM core commit from 5.1 that
  doesn't properly trim special IOs (e.g. discards) relative to
  corresponding target's max_io_len_target_boundary()"

* tag 'for-5.2/dm-fix-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: make sure to obey max_io_len_target_boundary

1 files changed, 3 insertions, 1 deletions

diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 1fb1333fefec..997385c1ca54 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1469,7 +1469,7 @@ static unsigned get_num_write_zeroes_bios(struct dm_target *ti)
 static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti,
                                        unsigned num_bios)
 {
-        unsigned len = ci->sector_count;
+        unsigned len;
 
         /*
          * Even though the device advertised support for this type of
@@ -1480,6 +1480,8 @@ static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *
         if (!num_bios)
                 return -EOPNOTSUPP;
 
+        len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
+
         __send_duplicate_bios(ci, ti, num_bios, &len);
 
         ci->sector += len;