From: Takaya Saeki <takayas@chromium.org>
Date: Tue, 3 Sep 2024 10:21:00 +0000 (+0000)
Subject: filemap: fix the last_index of mm_filemap_get_pages
X-Git-Tag: v6.12-rc1~115^2~60
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=fc1b43c422f3deee0cfc221b071c3863dc077646;p=thirdparty%2Fkernel%2Flinux.git

filemap: fix the last_index of mm_filemap_get_pages

In commit b6273b55d885 ("filemap: add trace events for get_pages,
map_pages, and fault"), mm_filemap_get_pages was added to trace page cache
access.  However, it tracks an extra page beyond the end of the accessed
range.  This patch fixes it by replacing last_index with last_index - 1.

Link: https://lkml.kernel.org/r/20240903102100.70405-1-takayas@chromium.org
Fixes: b6273b55d885 ("filemap: add trace events for get_pages, map_pages, and fault")
Signed-off-by: Takaya Saeki <takayas@chromium.org>
Cc: Junichi Uekawa <uekawa@chromium.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/filemap.c b/mm/filemap.c
index 88a2ed0084748..7eb4637ea199c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2567,7 +2567,7 @@ retry:
 			goto err;
 	}
 
-	trace_mm_filemap_get_pages(mapping, index, last_index);
+	trace_mm_filemap_get_pages(mapping, index, last_index - 1);
 	return 0;
 err:
 	if (err < 0)