From d35bd764e6899a7bea71958f08d16cea5bfa1919 Mon Sep 17 00:00:00 2001
From: Mikulas Patocka <mpatocka@redhat.com>
Date: Fri, 19 Jun 2020 11:51:34 -0400
Subject: [PATCH] dm writecache: add cond_resched to loop in
 persistent_memory_claim()
Git-commit: d35bd764e6899a7bea71958f08d16cea5bfa1919
Patch-mainline: v5.8-rc3
References: git fixes (block drivers)

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: Coly Li <colyli@suse.de>

---
 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 6b28990b1d84..30505d70f423 100644
--- 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);
-- 
2.26.2