Re: [PATCH v2 07/12] rbd: Enable lock context analysis

[Nilay Shroff <nilay@linux.ibm.com>]

On 7/31/26 1:28 AM, Bart Van Assche wrote:
> Add lock context annotations.
> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>   drivers/block/rbd.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
> index 1f1c2810f6ee..f0f7a94e3e3e 100644
> --- a/drivers/block/rbd.c
> +++ b/drivers/block/rbd.c
> @@ -4183,6 +4183,7 @@ static void rbd_acquire_lock(struct work_struct *work)
>   }
>   
>   static bool rbd_quiesce_lock(struct rbd_device *rbd_dev)
> +	__must_hold(&rbd_dev->lock_rwsem)
>   {
>   	dout("%s rbd_dev %p\n", __func__, rbd_dev);
>   	lockdep_assert_held_write(&rbd_dev->lock_rwsem);
> @@ -4227,6 +4228,7 @@ static void __rbd_release_lock(struct rbd_device *rbd_dev)
>    * lock_rwsem must be held for write
>    */
>   static void rbd_release_lock(struct rbd_device *rbd_dev)
> +	__must_hold(&rbd_dev->lock_rwsem)
>   {
>   	if (!rbd_quiesce_lock(rbd_dev))
>   		return;
> @@ -4583,6 +4585,7 @@ static void rbd_unregister_watch(struct rbd_device *rbd_dev)
>    * lock_rwsem must be held for write
>    */
>   static void rbd_reacquire_lock(struct rbd_device *rbd_dev)
> +	__must_hold(&rbd_dev->lock_rwsem)
>   {
>   	struct ceph_osd_client *osdc = &rbd_dev->rbd_client->client->osdc;
>   	char cookie[32];
> @@ -6780,6 +6783,7 @@ static void rbd_dev_device_release(struct rbd_device *rbd_dev)
>    * upon return.
>    */
>   static int rbd_dev_device_setup(struct rbd_device *rbd_dev)
> +	__releases(&rbd_dev->header_rwsem)
>   {
>   	int ret;
>   
> @@ -6881,6 +6885,7 @@ static void rbd_dev_image_release(struct rbd_device *rbd_dev)
>    * with @depth == 0.
>    */
>   static int rbd_dev_image_probe(struct rbd_device *rbd_dev, int depth)
> +	__context_unsafe(conditional locking on @depth)
>   {
>   	bool need_watch = !rbd_is_ro(rbd_dev);
>   	int ret;
> @@ -7134,6 +7139,9 @@ static ssize_t do_rbd_add(const char *buf, size_t count)
>   	if (rc < 0)
>   		goto err_out_rbd_dev;
>   
> +	/* Acquired by rbd_dev_image_probe(rbd_dev, 0) */
> +	__acquire(&rbd_dev->header_rwsem);
> +
>   	if (rbd_dev->opts->alloc_size > rbd_dev->layout.object_size) {
>   		rbd_warn(rbd_dev, "alloc_size adjusted to %u",
>   			 rbd_dev->layout.object_size);


In addition to the above annotations, it looks like several variables and structure members
are consistently protected by specific locks:

1. rbd_dev_list is guarded by rbd_dev_list_lock.
2. rbd_client_list is guarded by rbd_client_list_lock.
3. rbd_device::acquiring_list and rbd_device::running_list are guarded by
    rbd_device::lock_lists_lock.
4. rbd_device::object_map is guarded by rbd_device::object_map_lock.
5. rbd_device::watch_cookie, rbd_device::watch_state, and rbd_device::watch_handle
    are guarded by rbd_device::watch_mutex.
6. rbd_device::lock_state and rbd_device::lock_cookie are guarded by rbd_device::lock_rwsem.

So I think we should add the corresponding `__guarded_by(...)` annotations for these
fields as part of enabling lock context analysis for this driver.

Thanks,
--Nilay