From 041c881a0ba8a75f71118bd9766b78f04beed469 Mon Sep 17 00:00:00 2001

From: Karthikeyan Kathirvel <kathirve@codeaurora.org>

Date: Thu, 11 Mar 2021 10:59:07 +0530

Subject: [PATCH] mac80211: choose first enabled channel for monitor

Git-commit: 041c881a0ba8a75f71118bd9766b78f04beed469

Patch-mainline: v5.12-rc5

References: git-fixes

Even if the first channel from sband channel list is invalid

or disabled mac80211 ends up choosing it as the default channel

for monitor interfaces, making them not usable.

Fix this by assigning the first available valid or enabled

channel instead.

Signed-off-by: Karthikeyan Kathirvel <kathirve@codeaurora.org>

Link: https://lore.kernel.org/r/1615440547-7661-1-git-send-email-kathirve@codeaurora.org

[reword commit message, comment, code cleanups]

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

Acked-by: Takashi Iwai <tiwai@suse.de>

---

 net/mac80211/main.c | 13 ++++++++++++-

 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/net/mac80211/main.c b/net/mac80211/main.c

index 4f3f8bb58e76..1b9c82616606 100644

--- a/net/mac80211/main.c

+++ b/net/mac80211/main.c

@@ -973,8 +973,19 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)

 			continue;

 		if (!dflt_chandef.chan) {

+			/*

+			 * Assign the first enabled channel to dflt_chandef

+			 * from the list of channels

+			 */

+			for (i = 0; i < sband->n_channels; i++)

+				if (!(sband->channels[i].flags &

+						IEEE80211_CHAN_DISABLED))

+					break;

+			/* if none found then use the first anyway */

+			if (i == sband->n_channels)

+				i = 0;

 			cfg80211_chandef_create(&dflt_chandef,

-						&sband->channels[0],

+						&sband->channels[i],

 						NL80211_CHAN_NO_HT);

 			/* init channel we're on */

 			if (!local->use_chanctx && !local->_oper_chandef.chan) {

-- 

2.26.2