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From:   greearb@candelatech.com
To:     linux-wireless@vger.kernel.org
Cc:     johannes@sipsolutions.net, Ben Greear <greearb@candelatech.com>
Subject: [PATCH 01/10] mac80211: Add comment about tx on monitor devs.
Date:   Fri,  8 Nov 2019 11:42:02 -0800
Message-Id: <20191108194210.23618-2-greearb@candelatech.com>
In-Reply-To: <20191108194210.23618-1-greearb@candelatech.com>
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From: Ben Greear <greearb@candelatech.com>

This tries to encapsulate email conversation with Johannes on
this topic for posterity's sake.

Signed-off-by: Ben Greear <greearb@candelatech.com>
---
 net/mac80211/tx.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 1fa422782905..05982538c3cf 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -2277,6 +2277,12 @@ netdev_tx_t ieee80211_monitor_start_xmit(struct sk_buff *skb,
 	 * isn't always enough to find the interface to use; for proper
 	 * VLAN/WDS support we will need a different mechanism (which
 	 * likely isn't going to be monitor interfaces).
+	 *
+	 * I had a question about why we need to do this, and the answer
+	 * is that old hostap used this API and expects it to work like this,
+	 * and also monitor vdevs are not directly mapped into the driver
+	 * (and have no chantx in my case, at least), so you cannot directly
+	 * transmit on a monitor port anyway.
 	 */
 	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
-- 
2.20.1