[PATCH v3 04/18] nvme: add context annotations for nvme_ns_head::requeue_list

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

nvme_ns_head::requeue_list is protected by
nvme_ns_head::requeue_lock. Annotate requeue_list with
__guarded_by(&requeue_lock) so that Clang's context analysis can
validate accesses to the list.

For zero-initialized objects, bio_list_init() is a no-op. Remove the
redundant initialization from nvme_mpath_alloc_disk(), which
initializes nvme_ns_head::requeue_list. Besides simplifying the code,
this also avoids a false positive from Clang's context analysis, which
would otherwise warn about accessing nvme_ns_head::requeue_list
without holding nvme_ns_head::requeue_lock.

Signed-off-by: Nilay Shroff <nilay@linux.ibm.com>
---
 drivers/nvme/host/multipath.c | 1 -
 drivers/nvme/host/nvme.h      | 3 ++-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index e4ec5d5e2df1..67fd0752e894 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -732,7 +732,6 @@ int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl, struct nvme_ns_head *head)
 	struct queue_limits lim;
 
 	mutex_init(&head->lock);
-	bio_list_init(&head->requeue_list);
 	spin_lock_init(&head->requeue_lock);
 	INIT_WORK(&head->requeue_work, nvme_requeue_work);
 	INIT_WORK(&head->partition_scan_work, nvme_partition_scan_work);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index b7c3ba9c0fc1..5e746ae1c805 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -561,7 +561,8 @@ struct nvme_ns_head {
 	u16			nr_plids;
 	u16			*plids;
 #ifdef CONFIG_NVME_MULTIPATH
-	struct bio_list		requeue_list;
+	struct bio_list		requeue_list
+		__guarded_by(&requeue_lock);
 	spinlock_t		requeue_lock;
 	struct work_struct	requeue_work;
 	struct work_struct	partition_scan_work;
-- 
2.53.0