From: Amol Grover <frextrite@gmail.com>
To: Santosh Shilimkar <ssantosh@kernel.org>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH] drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists
Date: Fri, 10 Jan 2020 18:02:13 +0530 [thread overview]
Message-ID: <20200110123212.26756-1-frextrite@gmail.com> (raw)
inst->handles is traversed using list_for_each_entry_rcu
outside an RCU read-side critical section but under the protection
of knav_dev_lock.
Hence, add corresponding lockdep expression 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/soc/ti/knav_qmss_queue.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
index 1ccc9064e1eb..888dc091c63b 100644
--- a/drivers/soc/ti/knav_qmss_queue.c
+++ b/drivers/soc/ti/knav_qmss_queue.c
@@ -25,6 +25,8 @@
static struct knav_device *kdev;
static DEFINE_MUTEX(knav_dev_lock);
+#define knav_dev_lock_held() \
+ lockdep_is_held(&knav_dev_lock)
/* Queue manager register indices in DTS */
#define KNAV_QUEUE_PEEK_REG_INDEX 0
@@ -52,8 +54,9 @@ static DEFINE_MUTEX(knav_dev_lock);
#define knav_queue_idx_to_inst(kdev, idx) \
(kdev->instances + (idx << kdev->inst_shift))
-#define for_each_handle_rcu(qh, inst) \
- list_for_each_entry_rcu(qh, &inst->handles, list)
+#define for_each_handle_rcu(qh, inst) \
+ list_for_each_entry_rcu(qh, &inst->handles, list, \
+ rcu_read_lock_held() || knav_dev_lock_held())
#define for_each_instance(idx, inst, kdev) \
for (idx = 0, inst = kdev->instances; \
--
2.24.1
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next reply other threads:[~2020-01-10 12:41 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 12:32 Amol Grover [this message]
2020-01-11 16:39 ` [Linux-kernel-mentees] [PATCH] drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists kbuild test robot
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