lkml.org 
[lkml]   [2009]   [Mar]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] memdup_user: introduce, fix
Always use GFP_KERNEL in kmalloc(), since copy_from_user() can sleep and
cause pagefault, thus it's pointless to use GFP_NOFS or GFP_ATOMIC here.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---

Against memdup_user-introduce.patch

---
include/linux/string.h | 2 +-
mm/util.c | 10 +++++++---
2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/include/linux/string.h b/include/linux/string.h
index 79f30f3..0863885 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -12,7 +12,7 @@
#include <linux/stddef.h> /* for NULL */

extern char *strndup_user(const char __user *, long);
-extern void *memdup_user(const void __user *, size_t, gfp_t);
+extern void *memdup_user(const void __user *, size_t);

/*
* Include machine specific inline routines
diff --git a/mm/util.c b/mm/util.c
index 3d21c21..7c122e4 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -74,15 +74,19 @@ EXPORT_SYMBOL(kmemdup);
*
* @src: source address in user space
* @len: number of bytes to copy
- * @gfp: GFP mask to use
*
* Returns an ERR_PTR() on failure.
*/
-void *memdup_user(const void __user *src, size_t len, gfp_t gfp)
+void *memdup_user(const void __user *src, size_t len)
{
void *p;

- p = kmalloc_track_caller(len, gfp);
+ /*
+ * Always use GFP_KERNEL, since copy_from_user() can sleep and
+ * cause pagefault, which makes it pointless to use GFP_NOFS
+ * or GFP_ATOMIC.
+ */
+ p = kmalloc_track_caller(len, GFP_KERNEL);
if (!p)
return ERR_PTR(-ENOMEM);

--
1.5.4.rc3

\
 
 \ /
  Last update: 2009-03-10 02:49    [W:0.025 / U:0.032 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site