Re: [PATCH v4 3/8] fuse: {io-uring} Use bitmaps to track registered queues

[Luis Henriques <luis@igalia.com>]

On Fri, Apr 24 2026, Bernd Schubert wrote:

> On 4/24/26 17:04, Luis Henriques wrote:
>> On Mon, Apr 13 2026, Bernd Schubert via B4 Relay wrote:
>> 
>>> From: Bernd Schubert <bschubert@ddn.com>
>>>
>>> Add per-CPU and per-NUMA node bitmasks to track which
>>> io-uring queues are registered.
>>>
>>> Signed-off-by: Bernd Schubert <bschubert@ddn.com>
>>> ---
>>>  fs/fuse/dev_uring.c   | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++
>>>  fs/fuse/dev_uring_i.h | 20 ++++++++++++++
>>>  2 files changed, 93 insertions(+)
>>>
>>> diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c
>>> index 08c49e5b65ee950a9749a034b1e9d0a8883e1d31..1d1305d38efa07641128a865aec1745d2e040b93 100644
>>> --- a/fs/fuse/dev_uring.c
>>> +++ b/fs/fuse/dev_uring.c
>>> @@ -186,6 +186,25 @@ bool fuse_uring_request_expired(struct fuse_conn *fc)
>>>  	return false;
>>>  }
>>>  
>>> +static void fuse_ring_destruct_q_map(struct fuse_queue_map *q_map)
>>> +{
>>> +	free_cpumask_var(q_map->registered_q_mask);
>>> +	kfree(q_map->cpu_to_qid);
>>> +}
>>> +
>>> +static void fuse_uring_destruct_q_masks(struct fuse_ring *ring)
>>> +{
>>> +	int node;
>>> +
>>> +	fuse_ring_destruct_q_map(&ring->q_map);
>>> +
>>> +	if (ring->numa_q_map) {
>>> +		for (node = 0; node < ring->nr_numa_nodes; node++)
>>> +			fuse_ring_destruct_q_map(&ring->numa_q_map[node]);
>>> +		kfree(ring->numa_q_map);
>>> +	}
>>> +}
>>> +
>>>  void fuse_uring_destruct(struct fuse_conn *fc)
>>>  {
>>>  	struct fuse_ring *ring = fc->ring;
>>> @@ -217,11 +236,44 @@ void fuse_uring_destruct(struct fuse_conn *fc)
>>>  		ring->queues[qid] = NULL;
>>>  	}
>>>  
>>> +	fuse_uring_destruct_q_masks(ring);
>>>  	kfree(ring->queues);
>>>  	kfree(ring);
>>>  	fc->ring = NULL;
>>>  }
>>>  
>>> +static int fuse_uring_init_q_map(struct fuse_queue_map *q_map, size_t nr_cpu)
>>> +{
>>> +	if (!zalloc_cpumask_var(&q_map->registered_q_mask, GFP_KERNEL_ACCOUNT))
>>> +		return -ENOMEM;
>>> +
>>> +	q_map->cpu_to_qid = kzalloc_objs(*q_map->cpu_to_qid, nr_cpu,
>>> +					 GFP_KERNEL_ACCOUNT);
>>> +
>> 
>> Missing NULL check here (and corresponding call to free_cpumask_var()).
>> 
>>>
>>> +	return 0;
>>> +}
>>> +
>>> +static int fuse_uring_create_q_masks(struct fuse_ring *ring)
>>> +{
>>> +	int err, node;
>>> +
>>> +	err = fuse_uring_init_q_map(&ring->q_map, ring->max_nr_queues);
>>> +	if (err)
>>> +		return err;
>>> +
>>> +	ring->numa_q_map = kzalloc_objs(*ring->numa_q_map, ring->nr_numa_nodes,
>>> +					GFP_KERNEL_ACCOUNT);
>>> +	if (!ring->numa_q_map)
>>> +		return -ENOMEM;
>> 
>> Missing call to fuse_ring_destruct_q_map().
>> 
>>> +	for (node = 0; node < ring->nr_numa_nodes; node++) {
>>> +		err = fuse_uring_init_q_map(&ring->numa_q_map[node],
>>> +					   ring->max_nr_queues);
>>> +		if (err)
>>> +			return err;
>> 
>> Cleanup also missing here.
>
> I don't think so, for either of both, see error handling in
> fuse_uring_create_q_masks().

Doh! you're right.  The only fuse_uring_create_q_masks() call site is
fuse_uring_create(), which will then call fuse_uring_destruct_q_masks() on
error.  Sorry for the noise :-/

Cheers,
-- 
Luís