[PATCH] mm/mmap.c: optimization of do_mmap_pgoff function

[Piotr Kwapulinski]

The simple check for zero length memory mapping may be performed
earlier. It causes that in case of zero length memory mapping some
unnecessary code is not executed at all. It does not make the code less
readable and saves some CPU cycles.

Signed-off-by: Piotr Kwapulinski <kwapulinski.piotr@xxxxxxxxx>
---
 mm/mmap.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index bb50cac..aa632ad 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1258,6 +1258,9 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 
 	*populate = 0;
 
+	if (!len)
+		return -EINVAL;
+
 	/*
 	 * Does the application expect PROT_READ to imply PROT_EXEC?
 	 *
@@ -1268,9 +1271,6 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 		if (!(file && (file->f_path.mnt->mnt_flags & MNT_NOEXEC)))
 			prot |= PROT_EXEC;
 
-	if (!len)
-		return -EINVAL;
-
 	if (!(flags & MAP_FIXED))
 		addr = round_hint_to_min(addr);
 
-- 
2.3.7

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/