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 5dd18f09ce7399df6fffe80d1598add46c395ae9 ]
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/multipath.c:168 RCU-list traversed in non-reader section!! drivers/nvme/host/multipath.c:227 RCU-list traversed in non-reader section!! drivers/nvme/host/multipath.c:260 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.
Signed-off-by: Breno Leitao leitao@debian.org Fixes: be647e2c76b2 ("nvme: use srcu for iterating namespace list") Signed-off-by: Keith Busch kbusch@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/nvme/host/multipath.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index 989d1e50fb8cc..32283301199f0 100644 --- a/drivers/nvme/host/multipath.c +++ b/drivers/nvme/host/multipath.c @@ -165,7 +165,8 @@ void nvme_kick_requeue_lists(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)) { if (!ns->head->disk) continue; kblockd_schedule_work(&ns->head->requeue_work); @@ -209,7 +210,8 @@ void nvme_mpath_clear_ctrl_paths(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)) { nvme_mpath_clear_current_path(ns); kblockd_schedule_work(&ns->head->requeue_work); } @@ -224,7 +226,8 @@ void nvme_mpath_revalidate_paths(struct nvme_ns *ns) int srcu_idx;
srcu_idx = srcu_read_lock(&head->srcu); - list_for_each_entry_rcu(ns, &head->list, siblings) { + list_for_each_entry_srcu(ns, &head->list, siblings, + srcu_read_lock_held(&head->srcu)) { if (capacity != get_capacity(ns->disk)) clear_bit(NVME_NS_READY, &ns->flags); } @@ -256,7 +259,8 @@ static struct nvme_ns *__nvme_find_path(struct nvme_ns_head *head, int node) int found_distance = INT_MAX, fallback_distance = INT_MAX, distance; struct nvme_ns *found = NULL, *fallback = NULL, *ns;
- list_for_each_entry_rcu(ns, &head->list, siblings) { + list_for_each_entry_srcu(ns, &head->list, siblings, + srcu_read_lock_held(&head->srcu)) { if (nvme_path_is_disabled(ns)) continue;
@@ -355,7 +359,8 @@ static struct nvme_ns *nvme_queue_depth_path(struct nvme_ns_head *head) unsigned int min_depth_opt = UINT_MAX, min_depth_nonopt = UINT_MAX; unsigned int depth;
- list_for_each_entry_rcu(ns, &head->list, siblings) { + list_for_each_entry_srcu(ns, &head->list, siblings, + srcu_read_lock_held(&head->srcu)) { if (nvme_path_is_disabled(ns)) continue;
@@ -423,7 +428,8 @@ static bool nvme_available_path(struct nvme_ns_head *head) if (!test_bit(NVME_NSHEAD_DISK_LIVE, &head->flags)) return NULL;
- list_for_each_entry_rcu(ns, &head->list, siblings) { + list_for_each_entry_srcu(ns, &head->list, siblings, + srcu_read_lock_held(&head->srcu)) { if (test_bit(NVME_CTRL_FAILFAST_EXPIRED, &ns->ctrl->flags)) continue; switch (ns->ctrl->state) { @@ -784,7 +790,8 @@ static int nvme_update_ana_state(struct nvme_ctrl *ctrl, return 0;
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)) { unsigned nsid; again: nsid = le32_to_cpu(desc->nsids[n]);