[dm-devel] [PATCH] dm-writecache: add cond_resched to a loop

[Mikulas Patocka]

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

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>
Cc: stable at vger.kernek.org

---
 drivers/md/dm-writecache.c |    2 ++
 1 file changed, 2 insertions(+)

Index: linux-2.6/drivers/md/dm-writecache.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-writecache.c	2020-05-18 15:43:24.218771000 +0200
+++ linux-2.6/drivers/md/dm-writecache.c	2020-05-18 17:13:43.239999000 +0200
@@ -282,6 +282,8 @@ static int persistent_memory_claim(struc
 			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);