6.6-stable review patch. If anyone has any objections, please let me know.
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From: Breno Leitao leitao@debian.org
[ Upstream commit 6d1c69945ce63a9fba22a4abf646cf960d878782 ]
The code currently uses list_for_each_entry_rcu() while holding an SRCU lock, triggering false positive warnings with CONFIG_PROVE_RCU=y enabled:
drivers/nvme/host/core.c:3770 RCU-list traversed in non-reader section!!
While the list is properly protected by SRCU lock, the code uses the wrong list traversal primitive. Replace list_for_each_entry_rcu() with list_for_each_entry_srcu() to correctly indicate SRCU-based protection and eliminate the false warning.
Fixes: be647e2c76b2 ("nvme: use srcu for iterating namespace list") Signed-off-by: Breno Leitao leitao@debian.org Reviewed-by: Christoph Hellwig hch@lst.de Signed-off-by: Keith Busch kbusch@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/host/core.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index b3c5460c6d768..965ca7d7a3de2 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -3544,7 +3544,8 @@ struct nvme_ns *nvme_find_get_ns(struct nvme_ctrl *ctrl, unsigned nsid) int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) { + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) { if (ns->head->ns_id == nsid) { if (!nvme_get_ns(ns)) continue; @@ -4555,7 +4556,8 @@ void nvme_mark_namespaces_dead(struct nvme_ctrl *ctrl) int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) blk_mark_disk_dead(ns->disk); srcu_read_unlock(&ctrl->srcu, srcu_idx); } @@ -4567,7 +4569,8 @@ void nvme_unfreeze(struct nvme_ctrl *ctrl) int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) blk_mq_unfreeze_queue(ns->queue); srcu_read_unlock(&ctrl->srcu, srcu_idx); clear_bit(NVME_CTRL_FROZEN, &ctrl->flags); @@ -4580,7 +4583,8 @@ int nvme_wait_freeze_timeout(struct nvme_ctrl *ctrl, long timeout) int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) { + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) { timeout = blk_mq_freeze_queue_wait_timeout(ns->queue, timeout); if (timeout <= 0) break; @@ -4596,7 +4600,8 @@ void nvme_wait_freeze(struct nvme_ctrl *ctrl) int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) blk_mq_freeze_queue_wait(ns->queue); srcu_read_unlock(&ctrl->srcu, srcu_idx); } @@ -4609,7 +4614,8 @@ void nvme_start_freeze(struct nvme_ctrl *ctrl)
set_bit(NVME_CTRL_FROZEN, &ctrl->flags); srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) blk_freeze_queue_start(ns->queue); srcu_read_unlock(&ctrl->srcu, srcu_idx); } @@ -4657,7 +4663,8 @@ void nvme_sync_io_queues(struct nvme_ctrl *ctrl) int srcu_idx;
srcu_idx = srcu_read_lock(&ctrl->srcu); - list_for_each_entry_rcu(ns, &ctrl->namespaces, list) + list_for_each_entry_srcu(ns, &ctrl->namespaces, list, + srcu_read_lock_held(&ctrl->srcu)) blk_sync_queue(ns->queue); srcu_read_unlock(&ctrl->srcu, srcu_idx); }