From:   chaitanya.mgit@gmail.com
To:     linux-wireless@vger.kernel.org, johannes@sipsolutions.net
Cc:     Chaitanya Tata <chaitanya.tata@bluwireless.co.uk>
Subject: [PATCH] cfg80211: reg: remove warn_on for a normal case
Date:   Thu, 24 Jan 2019 16:13:02 +0530
Message-Id: <20190124104302.26051-1-chaitanya.mgit@gmail.com>
Sender: linux-wireless-owner@vger.kernel.org
Precedence: bulk

From: Chaitanya Tata <chaitanya.tata@bluwireless.co.uk>

If there are simulatenous queries of regdb, then there might be a case
where multiple queries can trigger request_firmware_no_wait and can have
parallel callbacks being executed asynchronously. In this scenario we
might hit the WARN_ON.

So remove the warn_on, as the code already handles multiple callbacks
gracefully.

Signed-off-by: Chaitanya Tata <chaitanya.tata@bluwireless.co.uk>
---
 net/wireless/reg.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index cce4c16eaaa0..dd58b9909ac9 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -1024,8 +1024,13 @@ static void regdb_fw_cb(const struct firmware *fw, void *context)
 	}
 
 	rtnl_lock();
-	if (WARN_ON(regdb && !IS_ERR(regdb))) {
-		/* just restore and free new db */
+	if (regdb && !IS_ERR(regdb)) {
+		/* negative case - a bug
+		 * positive case - can happen due to race in case of multiple cb's in
+		 * queue, due to usage of asynchronous callback
+		 *
+		 * Either case, just restore and free new db.
+		 */
 	} else if (set_error) {
 		regdb = ERR_PTR(set_error);
 	} else if (fw) {
-- 
2.17.1