Re: [PATCH RFC v2 08/19] fuse: Add the queue configuration ioctl

[Josef Bacik <josef@toxicpanda.com>]

On Wed, May 29, 2024 at 08:00:43PM +0200, Bernd Schubert wrote:
> Signed-off-by: Bernd Schubert <bschubert@ddn.com>
> ---
>  fs/fuse/dev.c             | 10 +++++
>  fs/fuse/dev_uring.c       | 95 +++++++++++++++++++++++++++++++++++++++++++++++
>  fs/fuse/dev_uring_i.h     | 18 +++++++++
>  fs/fuse/fuse_i.h          |  3 ++
>  include/uapi/linux/fuse.h | 26 +++++++++++++
>  5 files changed, 152 insertions(+)
> 
> diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
> index 349c1d16b0df..78c05516da7f 100644
> --- a/fs/fuse/dev.c
> +++ b/fs/fuse/dev.c
> @@ -2395,6 +2395,12 @@ static long fuse_uring_ioctl(struct file *file, __u32 __user *argp)
>  	if (res != 0)
>  		return -EFAULT;
>  
> +	if (cfg.cmd == FUSE_URING_IOCTL_CMD_QUEUE_CFG) {
> +		res = _fuse_dev_ioctl_clone(file, cfg.qconf.control_fd);
> +		if (res != 0)
> +			return res;
> +	}
> +
>  	fud = fuse_get_dev(file);
>  	if (fud == NULL)
>  		return -ENODEV;
> @@ -2424,6 +2430,10 @@ static long fuse_uring_ioctl(struct file *file, __u32 __user *argp)
>  		if (res != 0)
>  			return res;
>  		break;
> +		case FUSE_URING_IOCTL_CMD_QUEUE_CFG:
> +			fud->uring_dev = 1;
> +			res = fuse_uring_queue_cfg(fc->ring, &cfg.qconf);
> +		break;
>  	default:
>  		res = -EINVAL;
>  	}
> diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
> index 9491bdaa5716..2c0ccb378908 100644
> --- a/fs/fuse/dev_uring.c
> +++ b/fs/fuse/dev_uring.c
> @@ -144,6 +144,39 @@ static char *fuse_uring_alloc_queue_buf(int size, int node)
>  	return buf ? buf : ERR_PTR(-ENOMEM);
>  }
>  
> +/*
> + * mmaped allocated buffers, but does not know which queue that is for
> + * This ioctl uses the userspace address as key to identify the kernel address
> + * and assign it to the kernel side of the queue.
> + */
> +static int fuse_uring_ioctl_mem_reg(struct fuse_ring *ring,
> +				    struct fuse_ring_queue *queue,
> +				    uint64_t uaddr)
> +{
> +	struct rb_node *node;
> +	struct fuse_uring_mbuf *entry;
> +	int tag;
> +
> +	node = rb_find((const void *)uaddr, &ring->mem_buf_map,
> +		       fuse_uring_rb_tree_buf_cmp);
> +	if (!node)
> +		return -ENOENT;
> +	entry = rb_entry(node, struct fuse_uring_mbuf, rb_node);
> +
> +	rb_erase(node, &ring->mem_buf_map);
> +
> +	queue->queue_req_buf = entry->kbuf;
> +
> +	for (tag = 0; tag < ring->queue_depth; tag++) {
> +		struct fuse_ring_ent *ent = &queue->ring_ent[tag];
> +
> +		ent->rreq = entry->kbuf + tag * ring->req_buf_sz;
> +	}
> +
> +	kfree(node);
> +	return 0;
> +}
> +
>  /**
>   * fuse uring mmap, per ring qeuue.
>   * Userpsace maps a kernel allocated ring/queue buffer. For numa awareness,
> @@ -234,3 +267,65 @@ fuse_uring_mmap(struct file *filp, struct vm_area_struct *vma)
>  
>  	return ret;
>  }
> +
> +int fuse_uring_queue_cfg(struct fuse_ring *ring,
> +			 struct fuse_ring_queue_config *qcfg)
> +{
> +	int tag;
> +	struct fuse_ring_queue *queue;
> +
> +	if (qcfg->qid >= ring->nr_queues) {
> +		pr_info("fuse ring queue config: qid=%u >= nr-queues=%zu\n",
> +			qcfg->qid, ring->nr_queues);
> +		return -EINVAL;
> +	}
> +	queue = fuse_uring_get_queue(ring, qcfg->qid);
> +
> +	if (queue->configured) {
> +		pr_info("fuse ring qid=%u already configured!\n", queue->qid);
> +		return -EALREADY;
> +	}
> +
> +	mutex_lock(&ring->start_stop_lock);
> +	fuse_uring_ioctl_mem_reg(ring, queue, qcfg->uaddr);
> +	mutex_unlock(&ring->start_stop_lock);

You're not handling the error here.  Thanks,

Josef