Commit 4b6ec919 authored by Feng Liu's avatar Feng Liu Committed by Michael S. Tsirkin
Browse files

virtio_ring: Use const to annotate read-only pointer params 



Add const to make the read-only pointer parameters clear, similar to
many existing functions.

To implement this change, the commit also introduces the use of
`container_of_const` to implement `to_vvq`, which ensures the const-ness
of read-only parameters and avoids accidental modification of their
members.

Signed-off-by: default avatarFeng Liu <feliu@nvidia.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Reviewed-by: default avatarParav Pandit <parav@nvidia.com>
Reviewed-by: default avatarGavin Li <gavinl@nvidia.com>
Reviewed-by: default avatarBodong Wang <bodong@nvidia.com>

Message-Id: <20230310053428.3376-4-feliu@nvidia.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent 1adbd6b2

drivers/virtio/virtio_ring.c

+18 −18
Original line number Diff line number Diff line
@@ -231,9 +231,9 @@ static void vring_free(struct virtqueue *_vq); 
 * Helpers.

 */



#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)

#define to_vvq(_vq) container_of_const(_vq, struct vring_virtqueue, vq)



static bool virtqueue_use_indirect(struct vring_virtqueue *vq,

static bool virtqueue_use_indirect(const struct vring_virtqueue *vq,

				   unsigned int total_sg)

{

	/*
@@ -269,7 +269,7 @@ static bool virtqueue_use_indirect(struct vring_virtqueue *vq, 
 * unconditionally on data path.

 */



static bool vring_use_dma_api(struct virtio_device *vdev)

static bool vring_use_dma_api(const struct virtio_device *vdev)

{

	if (!virtio_has_dma_quirk(vdev))

		return true;
@@ -289,7 +289,7 @@ static bool vring_use_dma_api(struct virtio_device *vdev) 
	return false;

}



size_t virtio_max_dma_size(struct virtio_device *vdev)

size_t virtio_max_dma_size(const struct virtio_device *vdev)

{

	size_t max_segment_size = SIZE_MAX;
@@ -423,7 +423,7 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num) 
 */



static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq,

					   struct vring_desc *desc)

					   const struct vring_desc *desc)

{

	u16 flags;
@@ -1183,7 +1183,7 @@ static u16 packed_last_used(u16 last_used_idx) 
}



static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,

				     struct vring_desc_extra *extra)

				     const struct vring_desc_extra *extra)

{

	u16 flags;
@@ -1206,7 +1206,7 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq, 
}



static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,

				   struct vring_packed_desc *desc)

				    const struct vring_packed_desc *desc)

{

	u16 flags;
@@ -2786,10 +2786,10 @@ EXPORT_SYMBOL_GPL(vring_transport_features); 
 * Returns the size of the vring.  This is mainly used for boasting to

 * userspace.  Unlike other operations, this need not be serialized.

 */

unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)

unsigned int virtqueue_get_vring_size(const struct virtqueue *_vq)

{



	struct vring_virtqueue *vq = to_vvq(_vq);

	const struct vring_virtqueue *vq = to_vvq(_vq);



	return vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num;

}
@@ -2819,9 +2819,9 @@ void __virtqueue_unbreak(struct virtqueue *_vq) 
}

EXPORT_SYMBOL_GPL(__virtqueue_unbreak);



bool virtqueue_is_broken(struct virtqueue *_vq)

bool virtqueue_is_broken(const struct virtqueue *_vq)

{

	struct vring_virtqueue *vq = to_vvq(_vq);

	const struct vring_virtqueue *vq = to_vvq(_vq);



	return READ_ONCE(vq->broken);

}
@@ -2868,9 +2868,9 @@ void __virtio_unbreak_device(struct virtio_device *dev) 
}

EXPORT_SYMBOL_GPL(__virtio_unbreak_device);



dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)

dma_addr_t virtqueue_get_desc_addr(const struct virtqueue *_vq)

{

	struct vring_virtqueue *vq = to_vvq(_vq);

	const struct vring_virtqueue *vq = to_vvq(_vq);



	BUG_ON(!vq->we_own_ring);
@@ -2881,9 +2881,9 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) 
}

EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);



dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)

dma_addr_t virtqueue_get_avail_addr(const struct virtqueue *_vq)

{

	struct vring_virtqueue *vq = to_vvq(_vq);

	const struct vring_virtqueue *vq = to_vvq(_vq);



	BUG_ON(!vq->we_own_ring);
@@ -2895,9 +2895,9 @@ dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) 
}

EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);



dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)

dma_addr_t virtqueue_get_used_addr(const struct virtqueue *_vq)

{

	struct vring_virtqueue *vq = to_vvq(_vq);

	const struct vring_virtqueue *vq = to_vvq(_vq);



	BUG_ON(!vq->we_own_ring);
@@ -2910,7 +2910,7 @@ dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) 
EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);



/* Only available for split ring */

const struct vring *virtqueue_get_vring(struct virtqueue *vq)

const struct vring *virtqueue_get_vring(const struct virtqueue *vq)

{

	return &to_vvq(vq)->split.vring;

}

include/linux/virtio.h

+7 −7
Original line number Diff line number Diff line
@@ -84,14 +84,14 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *vq); 


void *virtqueue_detach_unused_buf(struct virtqueue *vq);



unsigned int virtqueue_get_vring_size(struct virtqueue *vq);

unsigned int virtqueue_get_vring_size(const struct virtqueue *vq);



bool virtqueue_is_broken(struct virtqueue *vq);

bool virtqueue_is_broken(const struct virtqueue *vq);



const struct vring *virtqueue_get_vring(struct virtqueue *vq);

dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);

dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);

dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);

const struct vring *virtqueue_get_vring(const struct virtqueue *vq);

dma_addr_t virtqueue_get_desc_addr(const struct virtqueue *vq);

dma_addr_t virtqueue_get_avail_addr(const struct virtqueue *vq);

dma_addr_t virtqueue_get_used_addr(const struct virtqueue *vq);



int virtqueue_resize(struct virtqueue *vq, u32 num,

		     void (*recycle)(struct virtqueue *vq, void *buf));
@@ -147,7 +147,7 @@ int virtio_device_restore(struct virtio_device *dev); 
#endif

void virtio_reset_device(struct virtio_device *dev);



size_t virtio_max_dma_size(struct virtio_device *vdev);

size_t virtio_max_dma_size(const struct virtio_device *vdev);



#define virtio_device_for_each_vq(vdev, vq) \

	list_for_each_entry(vq, &vdev->vqs, list)