2018-07-23 08:46:14

by Jia-Ju Bai

Subject: [PATCH] crypto: virtio: Replace GFP_ATOMIC with GFP_KERNEL in __virtio_crypto_ablkcipher_do_req()

__virtio_crypto_ablkcipher_do_req() is never called in atomic context.

__virtio_crypto_ablkcipher_do_req() is only called by
virtio_crypto_ablkcipher_crypt_req(), which is only called by
virtcrypto_find_vqs() that is never called in atomic context.

__virtio_crypto_ablkcipher_do_req() calls kzalloc_node() with GFP_ATOMIC,
which is not necessary.
GFP_ATOMIC can be replaced with GFP_KERNEL.

This is found by a static analysis tool named DCNS written by myself.
I also manually check the kernel code before reporting it.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
drivers/crypto/virtio/virtio_crypto_algs.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/crypto/virtio/virtio_crypto_algs.c b/drivers/crypto/virtio/virtio_crypto_algs.c
index ba190cfa7aa1..83bcc83dae43 100644
--- a/drivers/crypto/virtio/virtio_crypto_algs.c
+++ b/drivers/crypto/virtio/virtio_crypto_algs.c
@@ -371,12 +371,12 @@ __virtio_crypto_ablkcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,

/* Why 3? outhdr + iv + inhdr */
sg_total = src_nents + dst_nents + 3;
- sgs = kzalloc_node(sg_total * sizeof(*sgs), GFP_ATOMIC,
+ sgs = kzalloc_node(sg_total * sizeof(*sgs), GFP_KERNEL,
dev_to_node(&vcrypto->vdev->dev));
if (!sgs)
return -ENOMEM;

- req_data = kzalloc_node(sizeof(*req_data), GFP_ATOMIC,
+ req_data = kzalloc_node(sizeof(*req_data), GFP_KERNEL,
dev_to_node(&vcrypto->vdev->dev));
if (!req_data) {
kfree(sgs);
@@ -432,7 +432,7 @@ __virtio_crypto_ablkcipher_do_req(struct virtio_crypto_sym_request *vc_sym_req,
* Avoid to do DMA from the stack, switch to using
* dynamically-allocated for the IV
*/
- iv = kzalloc_node(ivsize, GFP_ATOMIC,
+ iv = kzalloc_node(ivsize, GFP_KERNEL,
dev_to_node(&vcrypto->vdev->dev));
if (!iv) {
err = -ENOMEM;
--
2.17.0

2018-08-03 13:59:49

by Herbert Xu

Subject: Re: [PATCH] crypto: virtio: Replace GFP_ATOMIC with GFP_KERNEL in __virtio_crypto_ablkcipher_do_req()

On Mon, Jul 23, 2018 at 04:43:46PM +0800, Jia-Ju Bai wrote:
> __virtio_crypto_ablkcipher_do_req() is never called in atomic context.
>
> __virtio_crypto_ablkcipher_do_req() is only called by
> virtio_crypto_ablkcipher_crypt_req(), which is only called by
> virtcrypto_find_vqs() that is never called in atomic context.
>
> __virtio_crypto_ablkcipher_do_req() calls kzalloc_node() with GFP_ATOMIC,
> which is not necessary.
> GFP_ATOMIC can be replaced with GFP_KERNEL.
>
> This is found by a static analysis tool named DCNS written by myself.
> I also manually check the kernel code before reporting it.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>

Patch applied. Thanks.
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt