Re: [PATCH] virtio: Use const pointer for vu_dev

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Dec 16, 2024 at 11:41:41AM +0100, Laurent Vivier wrote:
> We don't modify the structure in some virtio functions.
> 
> Signed-off-by: Laurent Vivier <lvivier@redhat.com>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

I'm surprised we weren't already failing some of our static checks
because of this.

> ---
>  virtio.c    | 14 +++++++++-----
>  virtio.h    |  2 +-
>  vu_common.c |  2 +-
>  vu_common.h |  2 +-
>  4 files changed, 12 insertions(+), 8 deletions(-)
> 
> diff --git a/virtio.c b/virtio.c
> index a76de5e00222..625bac385f0c 100644
> --- a/virtio.c
> +++ b/virtio.c
> @@ -92,7 +92,8 @@
>   *
>   * Return: virtual address in our address space of the guest physical address
>   */
> -static void *vu_gpa_to_va(struct vu_dev *dev, uint64_t *plen, uint64_t guest_addr)
> +static void *vu_gpa_to_va(const struct vu_dev *dev, uint64_t *plen,
> +			  uint64_t guest_addr)
>  {
>  	unsigned int i;
>  
> @@ -210,7 +211,8 @@ static void virtqueue_get_head(const struct vu_virtq *vq,
>   *
>   * Return: -1 if there is an error, 0 otherwise
>   */
> -static int virtqueue_read_indirect_desc(struct vu_dev *dev, struct vring_desc *desc,
> +static int virtqueue_read_indirect_desc(const struct vu_dev *dev,
> +					struct vring_desc *desc,
>  					uint64_t addr, size_t len)
>  {
>  	uint64_t read_len;
> @@ -390,7 +392,7 @@ static inline void vring_set_avail_event(const struct vu_virtq *vq,
>   *
>   * Return: false on error, true otherwise
>   */
> -static bool virtqueue_map_desc(struct vu_dev *dev,
> +static bool virtqueue_map_desc(const struct vu_dev *dev,
>  			       unsigned int *p_num_sg, struct iovec *iov,
>  			       unsigned int max_num_sg,
>  			       uint64_t pa, size_t sz)
> @@ -426,7 +428,8 @@ static bool virtqueue_map_desc(struct vu_dev *dev,
>   *
>   * Return: -1 if there is an error, 0 otherwise
>   */
> -static int vu_queue_map_desc(struct vu_dev *dev, struct vu_virtq *vq, unsigned int idx,
> +static int vu_queue_map_desc(const struct vu_dev *dev,
> +			     struct vu_virtq *vq, unsigned int idx,
>  			     struct vu_virtq_element *elem)
>  {
>  	const struct vring_desc *desc = vq->vring.desc;
> @@ -504,7 +507,8 @@ static int vu_queue_map_desc(struct vu_dev *dev, struct vu_virtq *vq, unsigned i
>   *
>   * Return: -1 if there is an error, 0 otherwise
>   */
> -int vu_queue_pop(struct vu_dev *dev, struct vu_virtq *vq, struct vu_virtq_element *elem)
> +int vu_queue_pop(const struct vu_dev *dev, struct vu_virtq *vq,
> +		 struct vu_virtq_element *elem)
>  {
>  	unsigned int head;
>  	int ret;
> diff --git a/virtio.h b/virtio.h
> index 6410d60f9b3f..0af259df7dac 100644
> --- a/virtio.h
> +++ b/virtio.h
> @@ -170,7 +170,7 @@ static inline bool vu_has_protocol_feature(const struct vu_dev *vdev,
>  
>  bool vu_queue_empty(struct vu_virtq *vq);
>  void vu_queue_notify(const struct vu_dev *dev, struct vu_virtq *vq);
> -int vu_queue_pop(struct vu_dev *dev, struct vu_virtq *vq,
> +int vu_queue_pop(const struct vu_dev *dev, struct vu_virtq *vq,
>  		 struct vu_virtq_element *elem);
>  void vu_queue_detach_element(struct vu_virtq *vq);
>  void vu_queue_unpop(struct vu_virtq *vq);
> diff --git a/vu_common.c b/vu_common.c
> index 299b5a32e244..6d365bea5fe2 100644
> --- a/vu_common.c
> +++ b/vu_common.c
> @@ -73,7 +73,7 @@ void vu_init_elem(struct vu_virtq_element *elem, struct iovec *iov, int elem_cnt
>   *
>   * Return: number of elements used to contain the frame
>   */
> -int vu_collect(struct vu_dev *vdev, struct vu_virtq *vq,
> +int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
>  	       struct vu_virtq_element *elem, int max_elem,
>  	       size_t size, size_t *frame_size)
>  {
> diff --git a/vu_common.h b/vu_common.h
> index 901d97216c67..bd70faf3e226 100644
> --- a/vu_common.h
> +++ b/vu_common.h
> @@ -46,7 +46,7 @@ static inline void vu_set_element(struct vu_virtq_element *elem,
>  
>  void vu_init_elem(struct vu_virtq_element *elem, struct iovec *iov,
>  		  int elem_cnt);
> -int vu_collect(struct vu_dev *vdev, struct vu_virtq *vq,
> +int vu_collect(const struct vu_dev *vdev, struct vu_virtq *vq,
>  	       struct vu_virtq_element *elem, int max_elem, size_t size,
>  	       size_t *frame_size);
>  void vu_set_vnethdr(const struct vu_dev *vdev,

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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