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lib: make bitmap_parselist_user() a wrapper on bitmap_parselist()

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Patch series "lib: rework bitmap_parselist and tests", v5.

bitmap_parselist has been evolved from a pretty simple idea for long and
now lacks for refactoring.  It is not structured, has nested loops and a
set of opaque-named variables.

Things are more complicated because bitmap_parselist() is a part of user
interface, and its behavior should not change.

In this patchset
 - bitmap_parselist_user() made a wrapper on bitmap_parselist();
 - bitmap_parselist() reworked (patch 2);
 - time measurement in test_bitmap_parselist switched to ktime_get
   (patch 3);
 - new tests introduced (patch 4), and
 - bitmap_parselist_user() testing enabled with the same testset as
   bitmap_parselist() (patch 5).

This patch (of 5):

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.

Link: http://lkml.kernel.org/r/20190405173211.11373-2-ynorov@marvell.com
Signed-off-by: Yury Norov <ynorov@marvell.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Mike Travis <travis@sgi.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Yury Norov 2019-05-14 15:43:11 -07:00 committed by Linus Torvalds
parent 9f61589469
commit 281327c99b
1 changed files with 11 additions and 8 deletions
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19
lib/bitmap.c
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@ -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);