Eric Lee / smarc-ti-linux-kernel

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Commit 734a3fb29c45f76185006575332c34f4242ce94f

Authored by Joe Thornber
Committed by Greg Kroah-Hartman
1 parent 7a9cdc4c90

dm cache: fix spurious cell_defer when dealing with partial block at end of device 

commit f824a2af3dfbbb766c02e19df21f985bceadf0ee upstream.

We never bother caching a partial block that is at the back end of the
origin device.  No cell ever gets locked, but the calling code was
assuming it was and trying to release it.

Now the code only releases if the cell has been set to a non NULL
value.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Showing 1 changed file with 2 additions and 2 deletions Side-by-side Diff

drivers/md/dm-cache-target.c
Diff comments   View file @ 734a3fb
... ... @@ -2554,11 +2554,11 @@
2554 2554 static int cache_map(struct dm_target *ti, struct bio *bio)
2555 2555 {
2556 2556 int r;
2557   - struct dm_bio_prison_cell *cell;
  2557 + struct dm_bio_prison_cell *cell = NULL;
2558 2558 struct cache *cache = ti->private;
2559 2559  
2560 2560 r = __cache_map(cache, bio, &cell);
2561   - if (r == DM_MAPIO_REMAPPED) {
  2561 + if (r == DM_MAPIO_REMAPPED && cell) {
2562 2562 inc_ds(cache, bio, cell);
2563 2563 cell_defer(cache, cell, false);
2564 2564 }