[PATCH v6 08/26] virtio_ring: extract the logic of freeing vring
From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Date: 2022-02-24 08:11:59
Also in:
bpf, kvm, linux-remoteproc, linux-s390, linux-um, platform-driver-x86, virtualization
Subsystem:
the rest, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", Jason Wang
Introduce vring_free() to free the vring of vq. Prevent double free by setting vq->reset. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- drivers/virtio/virtio_ring.c | 25 ++++++++++++++++++++----- include/linux/virtio.h | 8 ++++++++ 2 files changed, 28 insertions(+), 5 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 039015823c53..0b5360052ac2 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c@@ -2442,14 +2442,10 @@ struct virtqueue *vring_new_virtqueue(unsigned int index, } EXPORT_SYMBOL_GPL(vring_new_virtqueue); -void vring_del_virtqueue(struct virtqueue *_vq) +static void __vring_free(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); - spin_lock(&vq->vq.vdev->vqs_list_lock); - list_del(&_vq->list); - spin_unlock(&vq->vq.vdev->vqs_list_lock); - if (vq->we_own_ring) { if (vq->packed_ring) { vring_free_queue(vq->vq.vdev,
@@ -2480,6 +2476,25 @@ void vring_del_virtqueue(struct virtqueue *_vq) kfree(vq->split.desc_state); kfree(vq->split.desc_extra); } +} + +static void vring_free(struct virtqueue *vq) +{ + __vring_free(vq); + vq->reset = VIRTIO_VQ_RESET_STEP_VRING_RELEASE; +} + +void vring_del_virtqueue(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + spin_lock(&vq->vq.vdev->vqs_list_lock); + list_del(&_vq->list); + spin_unlock(&vq->vq.vdev->vqs_list_lock); + + if (_vq->reset != VIRTIO_VQ_RESET_STEP_VRING_RELEASE) + __vring_free(_vq); + kfree(vq); } EXPORT_SYMBOL_GPL(vring_del_virtqueue);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index d59adc4be068..e3714e6db330 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h@@ -10,6 +10,13 @@ #include <linux/mod_devicetable.h> #include <linux/gfp.h> +enum virtio_vq_reset_step { + VIRTIO_VQ_RESET_STEP_NONE, + VIRTIO_VQ_RESET_STEP_DEVICE, + VIRTIO_VQ_RESET_STEP_VRING_RELEASE, + VIRTIO_VQ_RESET_STEP_VRING_ATTACH, +}; + /** * virtqueue - a queue to register buffers for sending or receiving. * @list: the chain of virtqueues for this device
@@ -33,6 +40,7 @@ struct virtqueue { unsigned int num_free; unsigned int num_max; void *priv; + enum virtio_vq_reset_step reset; }; int virtqueue_add_outbuf(struct virtqueue *vq,
--
2.31.0