[PATCH 4.19 129/131] dm writecache: add cond_resched to loop in persistent_memory_claim()

Sasha Levin
2020-06-29T20:14:47Z

From: Mikulas Patocka <mpatocka@redhat.com>

commit d35bd764e6899a7bea71958f08d16cea5bfa1919 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/md/dm-writecache.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 509552fc55fc7..cc028353f9d55 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -281,6 +281,8 @@ 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);
--
2.25.1