From 5dd18f09ce7399df6fffe80d1598add46c395ae9 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Tue, 5 Nov 2024 06:42:46 -0800 Subject: nvme/multipath: Fix RCU list traversal to use SRCU primitive 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 Fixes: be647e2c76b2 ("nvme: use srcu for iterating namespace list") Signed-off-by: Keith Busch --- drivers/nvme/host/multipath.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-) (limited to 'drivers/nvme/host') diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c index f04cfe3fb936..a85d190942bd 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); } @@ -257,7 +260,8 @@ 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; @@ -356,7 +360,8 @@ 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; @@ -424,7 +429,8 @@ 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 (nvme_ctrl_state(ns->ctrl)) { @@ -783,7 +789,8 @@ 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]); -- cgit v1.2.3-70-g09d2