Re: [PATCH v2 2/2] virtio_ring: check desc == NULL when packed and indirect
From: Jason Wang <hidden>
Date: 2021-09-28 03:20:24
On Mon, Sep 27, 2021 at 6:54 PM Xuan Zhuo [off-list ref] wrote:
In the case of packed, use indirect desc, since desc is allocated by
kmalloc_array(), we should check whether its return value is NULL.
This patch alloc desc inside virtqueue_add_packe(), if desc == NULL,
fall back to not using indirect.
Fixes: 1ce9e6055fa ("virtio_ring: introduce packed ring support")
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>Acked-by: Jason Wang <redacted>
quoted hunk ↗ jump to hunk
--- drivers/virtio/virtio_ring.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 91a46c4da87d..62323c27bfe4 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c@@ -1051,20 +1051,19 @@ static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg, static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, struct scatterlist *sgs[], + struct vring_packed_desc *desc, unsigned int total_sg, unsigned int out_sgs, unsigned int in_sgs, void *data, gfp_t gfp) { - struct vring_packed_desc *desc; struct scatterlist *sg; unsigned int i, n, err_idx; u16 head, id; dma_addr_t addr; head = vq->packed.next_avail_idx; - desc = alloc_indirect_packed(total_sg, gfp); if (unlikely(vq->vq.num_free < 1)) { pr_debug("Can't add buf len 1 - avail = 0\n");@@ -1191,9 +1190,14 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, BUG_ON(total_sg == 0); - if (virtqueue_use_indirect(_vq, total_sg)) - return virtqueue_add_indirect_packed(vq, sgs, total_sg, - out_sgs, in_sgs, data, gfp); + if (virtqueue_use_indirect(_vq, total_sg)) { + desc = alloc_indirect_packed(total_sg, gfp); + if (desc) + return virtqueue_add_indirect_packed(vq, sgs, desc, + total_sg, + out_sgs, in_sgs, + data, gfp); + } head = vq->packed.next_avail_idx; avail_used_flags = vq->packed.avail_used_flags; --2.31.0
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