nvme: add context annotations for nvme_queue::sq_lock

nvme_queue::sq_tail, nvme_queue::last_sq_tail and nvme_queue::sq_cmds
are protected by nvme_queue::sq_lock. Annotate each field with
__guarded_by(&sq_lock) and annotate helpers that access them with
__must_hold(&sq_lock) so that Clang's context analysis can validate
the locking requirements.

Access to nvme_queue::sq_tail used solely for tracing is annotated with
data_race(), as they only require a lockless snapshot of the value.

nvme_init_queue() initializes nvme_queue::sq_tail and
nvme_queue::last_sq_tail before the queue is published and thus do not
require nvme_queue::sq_lock protection. So annotate nvme_init_queue()
with context_unsafe() to suppress false positive context analyzer
warning.

nvme_free_queue() operate on queues which are no longer reachable, and
therefore do not require nvme_queue::sq_lock protection. Similarly,
nvme_alloc_sq_cmds() allocates memory for nvme_queue::sq_cmds for the
queue which is not yet published or in use and hence it's safe to
annotate all these helpers using context_unsafe.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
This commit is contained in:
Nilay Shroff 2026-07-13 17:24:16 +05:30 • committed by Keith Busch
commit 1f3d29bdca