From: Amol Grover <frextrite@gmail.com>
To: Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH] drivers: nvme: target: core: Pass lockdep expression to RCU lists
Date: Fri, 10 Jan 2020 18:53:58 +0530 [thread overview]
Message-ID: <20200110132356.27110-1-frextrite@gmail.com> (raw)
ctrl->subsys->namespaces and subsys->namespaces are traversed with
hlist_for_each_entry_rcu outside an RCU read-side critical section
but under the protection of subsys->lock.
Hence, add the corresponding lockdep expression to the list traversal
primitive to silence false-positive lockdep warnings, and
harden RCU lists.
Add macro for the corresponding lockdep expression to make the code
clean and concise.
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
drivers/nvme/target/core.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 28438b833c1b..7caab4ba6a04 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -15,6 +15,9 @@
#include "nvmet.h"
+#define subsys_lock_held() \
+ lockdep_is_held(&subsys->lock)
+
struct workqueue_struct *buffered_io_wq;
static const struct nvmet_fabrics_ops *nvmet_transports[NVMF_TRTYPE_MAX];
static DEFINE_IDA(cntlid_ida);
@@ -555,7 +558,8 @@ int nvmet_ns_enable(struct nvmet_ns *ns)
} else {
struct nvmet_ns *old;
- list_for_each_entry_rcu(old, &subsys->namespaces, dev_link) {
+ list_for_each_entry_rcu(old, &subsys->namespaces, dev_link,
+ subsys_lock_held()) {
BUG_ON(ns->nsid == old->nsid);
if (ns->nsid < old->nsid)
break;
@@ -1172,7 +1176,8 @@ static void nvmet_setup_p2p_ns_map(struct nvmet_ctrl *ctrl,
ctrl->p2p_client = get_device(req->p2p_client);
- list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link)
+ list_for_each_entry_rcu(ns, &ctrl->subsys->namespaces, dev_link,
+ subsys_lock_held())
nvmet_p2pmem_ns_add_p2p(ctrl, ns);
}
--
2.24.1
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next reply other threads:[~2020-01-10 13:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 13:23 Amol Grover [this message]
2020-01-10 15:47 ` [Linux-kernel-mentees] [PATCH] drivers: nvme: target: core: Pass lockdep expression to RCU lists Joel Fernandes
2020-01-10 16:31 ` Keith Busch
2020-01-10 17:10 ` Amol Grover
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