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From:   madhuparnabhowmik04@gmail.com
To:     stefanr@s5r6.in-berlin.de, paulmck@kernel.org,
        joel@joelfernandes.org
Cc:     linux1394-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, rcu@vger.kernel.org,
        linux-kernel-mentees@lists.linuxfoundation.org,
        frextrite@gmail.com,
        Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
Subject: [PATCH] drivers: firewire: core-transaction: Pass lockdep condition to address_handler_list iterator
Date:   Sat,  4 Jan 2020 20:12:15 +0530
Message-Id: <20200104144215.27590-1-madhuparnabhowmik04@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>

The address_handler_list is traversed with list_for_each_entry_rcu
with address_handler_list_lock held.
list_for_each_entry_rcu has built-in RCU and lock checking.
Use it for address_handler_list traversal.

Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik04@gmail.com>
---
 drivers/firewire/core-transaction.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index 404a035f104d..a15e70027932 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -61,6 +61,11 @@
 #define PHY_CONFIG_ROOT_ID(node_id)	((((node_id) & 0x3f) << 24) | (1 << 23))
 #define PHY_IDENTIFIER(id)		((id) << 30)
 
+static DEFINE_SPINLOCK(address_handler_list_lock);
+static LIST_HEAD(address_handler_list);
+
+#define address_handler_list_lock_held() lock_is_held(&(address_handler_list_lock).dep_map)
+
 /* returns 0 if the split timeout handler is already running */
 static int try_cancel_split_timeout(struct fw_transaction *t)
 {
@@ -485,7 +490,7 @@ static struct fw_address_handler *lookup_overlapping_address_handler(
 {
 	struct fw_address_handler *handler;
 
-	list_for_each_entry_rcu(handler, list, link) {
+	list_for_each_entry_rcu(handler, list, link, address_handler_list_lock_held()) {
 		if (handler->offset < offset + length &&
 		    offset < handler->offset + handler->length)
 			return handler;
@@ -514,8 +519,6 @@ static struct fw_address_handler *lookup_enclosing_address_handler(
 	return NULL;
 }
 
-static DEFINE_SPINLOCK(address_handler_list_lock);
-static LIST_HEAD(address_handler_list);
 
 const struct fw_address_region fw_high_memory_region =
 	{ .start = FW_MAX_PHYSICAL_RANGE, .end = 0xffffe0000000ULL, };
-- 
2.17.1