linux-kernel - [PATCH] crypto: virtio: Replace GFP_ATOMIC with GFP_KERNEL in __virtio_crypto_ablkcipher_do

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Date:   Mon, 23 Jul 2018 16:43:46 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     mst@...hat.com, jasowang@...hat.com, arei.gonglei@...wei.com,
        herbert@...dor.apana.org.au, davem@...emloft.net
Cc:     virtualization@...ts.linux-foundation.org,
        linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jia-Ju Bai <baijiaju1990@...il.com>
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 <baijiaju1990@...il.com>
---
 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