lkml.org 
[lkml]   [2019]   [Apr]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/5] lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()
Date
Currently we parse user data byte after byte which leads to
overcomplification of parsing algorithm. The only user of
bitmap_parselist_user() is not performance-critical, and so we
can duplicate user data to kernel buffer and simply call
bitmap_parselist(). This rework lets us unify and simplify
bitmap_parselist() and bitmap_parselist_user(), which is done
in the following patch.

Signed-off-by: Yury Norov <ynorov@marvell.com>
---
lib/bitmap.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 98872e9025da..79ed5538617b 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -632,19 +632,22 @@ EXPORT_SYMBOL(bitmap_parselist);
* @nmaskbits: size of bitmap, in bits.
*
* Wrapper for bitmap_parselist(), providing it with user buffer.
- *
- * We cannot have this as an inline function in bitmap.h because it needs
- * linux/uaccess.h to get the access_ok() declaration and this causes
- * cyclic dependencies.
*/
int bitmap_parselist_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
- if (!access_ok(ubuf, ulen))
- return -EFAULT;
- return __bitmap_parselist((const char __force *)ubuf,
- ulen, 1, maskp, nmaskbits);
+ char *buf;
+ int ret;
+
+ buf = memdup_user_nul(ubuf, ulen);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ ret = bitmap_parselist(buf, maskp, nmaskbits);
+
+ kfree(buf);
+ return ret;
}
EXPORT_SYMBOL(bitmap_parselist_user);

--
2.17.1
\
 
 \ /
  Last update: 2019-04-05 19:33    [W:0.062 / U:7.676 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site