dm writecache: add cond_resched to loop in persistent_memory_claim()

Add cond_resched() to a loop that fills in the mapper memory area
because the loop can be executed many times.

Fixes: 48debafe4f2fe ("dm: add writecache target")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 6b28990..30505d7 100644 (file)
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -282,6 +282,8 @@ static int persistent_memory_claim(struct dm_writecache *wc)
                        while (daa-- && i < p) {
                                pages[i++] = pfn_t_to_page(pfn);
                                pfn.val++;
+                               if (!(i & 15))
+                                       cond_resched();
                        }
                } while (i < p);
                wc->memory_map = vmap(pages, p, VM_MAP, PAGE_KERNEL);