Re: [PATCH v2 09/14] fuse: rearrange io-uring iovec and ent allocation logic

[Jeff Layton <jlayton@kernel.org>]

On Thu, 2026-04-02 at 09:28 -0700, Joanne Koong wrote:
> Move fuse_uring_get_iovec_from_sqe() to earlier in the file and
> move the allocation logic in fuse_uring_create_ring_ent() to the
> beginning of the function.
> 
> There is no change in logic, this is done to make the subsequent commit
> that adds buffer rings easier to review.
> 
> Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
> ---
>  fs/fuse/dev_uring.c | 78 ++++++++++++++++++++++++---------------------
>  1 file changed, 41 insertions(+), 37 deletions(-)
> 
> diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
> index cce8994241b7..a061f175b3fd 100644
> --- a/fs/fuse/dev_uring.c
> +++ b/fs/fuse/dev_uring.c
> @@ -277,6 +277,32 @@ static struct fuse_ring *fuse_uring_create(struct fuse_conn *fc)
>  	return res;
>  }
>  
> +/*
> + * sqe->addr is a ptr to an iovec array, iov[FUSE_URING_IOV_HEADERS] has the
> + * headers, iov[FUSE_URING_IOV_PAYLOAD] the payload
> + */
> +static int fuse_uring_get_iovec_from_sqe(const struct io_uring_sqe *sqe,
> +					 struct iovec iov[FUSE_URING_IOV_SEGS])
> +{
> +	struct iovec __user *uiov = u64_to_user_ptr(READ_ONCE(sqe->addr));
> +	struct iov_iter iter;
> +	ssize_t ret;
> +
> +	if (sqe->len != FUSE_URING_IOV_SEGS)
> +		return -EINVAL;
> +
> +	/*
> +	 * Direction for buffer access will actually be READ and WRITE,
> +	 * using write for the import should include READ access as well.
> +	 */
> +	ret = import_iovec(WRITE, uiov, FUSE_URING_IOV_SEGS,
> +			   FUSE_URING_IOV_SEGS, &iov, &iter);
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
>  static struct fuse_ring_queue *fuse_uring_create_queue(struct fuse_ring *ring,
>  						       int qid)
>  {
> @@ -1076,32 +1102,6 @@ static void fuse_uring_do_register(struct fuse_ring_ent *ent,
>  	}
>  }
>  
> -/*
> - * sqe->addr is a ptr to an iovec array, iov[FUSE_URING_IOV_HEADERS] has the
> - * headers, iov[FUSE_URING_IOV_PAYLOAD] the payload
> - */
> -static int fuse_uring_get_iovec_from_sqe(const struct io_uring_sqe *sqe,
> -					 struct iovec iov[FUSE_URING_IOV_SEGS])
> -{
> -	struct iovec __user *uiov = u64_to_user_ptr(READ_ONCE(sqe->addr));
> -	struct iov_iter iter;
> -	ssize_t ret;
> -
> -	if (sqe->len != FUSE_URING_IOV_SEGS)
> -		return -EINVAL;
> -
> -	/*
> -	 * Direction for buffer access will actually be READ and WRITE,
> -	 * using write for the import should include READ access as well.
> -	 */
> -	ret = import_iovec(WRITE, uiov, FUSE_URING_IOV_SEGS,
> -			   FUSE_URING_IOV_SEGS, &iov, &iter);
> -	if (ret < 0)
> -		return ret;
> -
> -	return 0;
> -}
> -
>  static struct fuse_ring_ent *
>  fuse_uring_create_ring_ent(struct io_uring_cmd *cmd,
>  			   struct fuse_ring_queue *queue)
> @@ -1112,40 +1112,44 @@ fuse_uring_create_ring_ent(struct io_uring_cmd *cmd,
>  	struct iovec *headers, *payload;
>  	int err;
>  
> +	ent = kzalloc_obj(*ent, GFP_KERNEL_ACCOUNT);
> +	if (!ent)
> +		return ERR_PTR(-ENOMEM);
> +
> +	INIT_LIST_HEAD(&ent->list);
> +
> +	ent->queue = queue;
> +
>  	err = fuse_uring_get_iovec_from_sqe(cmd->sqe, iov);
>  	if (err) {
>  		pr_info_ratelimited("Failed to get iovec from sqe, err=%d\n",
>  				    err);
> -		return ERR_PTR(err);
> +		goto error;
>  	}
>  
>  	err = -EINVAL;
>  	headers = &iov[FUSE_URING_IOV_HEADERS];
>  	if (headers->iov_len < sizeof(struct fuse_uring_req_header)) {
>  		pr_info_ratelimited("Invalid header len %zu\n", headers->iov_len);
> -		return ERR_PTR(err);
> +		goto error;
>  	}
>  
>  	payload = &iov[FUSE_URING_IOV_PAYLOAD];
>  	if (payload->iov_len < ring->max_payload_sz) {
>  		pr_info_ratelimited("Invalid req payload len %zu\n",
>  				    payload->iov_len);
> -		return ERR_PTR(err);
> +		goto error;
>  	}
>  
> -	err = -ENOMEM;
> -	ent = kzalloc_obj(*ent, GFP_KERNEL_ACCOUNT);
> -	if (!ent)
> -		return ERR_PTR(err);
> -
> -	INIT_LIST_HEAD(&ent->list);
> -
> -	ent->queue = queue;
>  	ent->headers = headers->iov_base;
>  	ent->payload = payload->iov_base;
>  
>  	atomic_inc(&ring->queue_refs);
>  	return ent;
> +
> +error:
> +	kfree(ent);
> +	return ERR_PTR(err);
>  }
>  
>  /*


Reviewed-by: Jeff Layton <jlayton@kernel.org>