From: Peter Zijlstra <peterz@infradead.org>
Date: Fri, 22 Nov 2024 11:47:48 +0000 (+0100)
Subject: mm/gup: Use raw_seqcount_try_begin()
X-Git-Tag: v6.14-rc1~186^2~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7528585290a1a1d4e0fb4b72261eb2d8c85de2d7;p=thirdparty%2Flinux.git

mm/gup: Use raw_seqcount_try_begin()

David pointed out that gup_fast() does exactly what the new
raw_seqcount_try_begin() does -- use it.

Suggested-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
---

diff --git a/mm/gup.c b/mm/gup.c
index 746070a1d8bfb..81ffbd8fec9c7 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -3351,8 +3351,7 @@ static unsigned long gup_fast(unsigned long start, unsigned long end,
 		return 0;
 
 	if (gup_flags & FOLL_PIN) {
-		seq = raw_read_seqcount(&current->mm->write_protect_seq);
-		if (seq & 1)
+		if (!raw_seqcount_try_begin(&current->mm->write_protect_seq, seq))
 			return 0;
 	}