From bb521c5de070b86a1e049e2dbf62328f717ff1e8 Mon Sep 17 00:00:00 2001 From: Nikanth Karthikesan <knikanth@suse.de> Date: Wed, 23 Sep 2009 15:57:09 -0700 Subject: [PATCH] /dev/zero: avoid repeated access_ok() checks In read_zero, we check for access_ok() once for the count bytes. It is unnecessarily checked again in clear_user. Use __clear_user, which does not check for access_ok(). Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- drivers/char/mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 0aede1d6a9ea..6c8b65d069e5 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -690,7 +690,7 @@ static ssize_t read_zero(struct file * file, char __user * buf, if (chunk > PAGE_SIZE) chunk = PAGE_SIZE; /* Just for latency reasons */ - unwritten = clear_user(buf, chunk); + unwritten = __clear_user(buf, chunk); written += chunk - unwritten; if (unwritten) break; -- GitLab