Subject: [RFC v1 1/2] mm/gup: fixup for 9947ea2c1e608e32 "mm/gup: track FOLL_PIN pages"

From: Claudio Imbrenda <[email-masked]>
Date: Fri, 28 Feb 2020 16:43:21 +0100

In case pin fails, we need to unpin, a simple put_page will not be enough

Signed-off-by: Claudio Imbrenda <[email-masked]>
---
 mm/gup.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/gup.c b/mm/gup.c
index f589299b0d4a..0b9a806898f3 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2134,7 +2134,10 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
 			goto pte_unmap;
 
 		if (unlikely(pte_val(pte) != pte_val(*ptep))) {
-			put_page(head);
+			if (flags & FOLL_GET)
+				put_page(head);
+			else if (flags & FOLL_PIN)
+				unpin_user_page(head);
 			goto pte_unmap;
 		}
 
-- 
2.24.1