[PATCH] btrfs:check-integrity.c: replace kmalloc with kmalloc_array

[PATCH] btrfs:check-integrity.c: replace kmalloc with kmalloc_array

[Himangi Saraogi]

This patch replaces kmalloc(size * nr, ) with kmalloc_array(nr, size)
as kmalloc_array() is preferred because it can check that the
calculation doesn't wrap and won't return a smaller allocation.

Reviewed-by: Zach Brown <zab@redhat.com>

Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
---
 fs/btrfs/check-integrity.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/check-integrity.c b/fs/btrfs/check-integrity.c
index 1c47be1..d61ffef 100644
--- a/fs/btrfs/check-integrity.c
+++ b/fs/btrfs/check-integrity.c
@@ -3031,8 +3031,9 @@ void btrfsic_submit_bio(int rw, struct bio *bio)
 			       (unsigned long long)bio->bi_sector, dev_bytenr,
 			       bio->bi_bdev);
 
-		mapped_datav = kmalloc(sizeof(*mapped_datav) * bio->bi_vcnt,
-				       GFP_NOFS);
+		mapped_datav = kmalloc_array(bio->bi_vcnt,
+					     sizeof(*mapped_datav),
+					     GFP_NOFS);
 		if (!mapped_datav)
 			goto leave;
 		for (i = 0; i < bio->bi_vcnt; i++) {
-- 
1.7.9.5

Re: [PATCH] btrfs:check-integrity.c: replace kmalloc with kmalloc_array

[David Sterba]

On Fri, Nov 01, 2013 at 06:16:00AM +0530, Himangi Saraogi wrote:
> This patch replaces kmalloc(size * nr, ) with kmalloc_array(nr, size)
> as kmalloc_array() is preferred because it can check that the
> calculation doesn't wrap and won't return a smaller allocation.

Can you please convert all the instances in one patch? Feel free to use
the following cocinelle script, that found ~16 places that could use
the conversion.

$ cat kmalloc_array.cocci
@ @
expression E1, E2, E3;
@@

* \(kmalloc\|kzalloc\)(E1 * E2, E3)
---

The output is not a straight patch, the instances have to be reviewed manually
because the order of nritems and size may differ at each location.

david