wifi: mac80211: fix monitor channel with chanctx emulation

After the channel context emulation, there were reports that
changing the monitor channel no longer works. This is because
those drivers don't have WANT_MONITOR_VIF, so the setting the
channel always exits out quickly.

Fix this by always allocating the virtual monitor sdata, and
simply not telling the driver about it unless it wanted to.
This way, we have an interface/sdata to bind the chanctx to,
and the emulation can work correctly.

Cc: [email protected]
Fixes: 0a44dfc07074 ("wifi: mac80211: simplify non-chanctx drivers")
Reported-and-tested-by: Savyasaachi Vanga <[email protected]>
Closes: https://lore.kernel.org/r/chwoymvpzwtbmzryrlitpwmta5j6mtndocxsyqvdyikqu63lon@gfds653hkknl
Link: https://msgid.link/20240612122351.b12d4a109dde.I1831a44417faaab92bea1071209abbe4efbe3fba@changeid
Signed-off-by: Johannes Berg <[email protected]>

diff --git a/net/mac80211/driver-ops.c b/net/mac80211/driver-ops.c
index dce37ba8ebe3744700e8dd83abf1ab3216957796..254d745832cbfeda8165c340abe21439067c7102 100644 (file)
--- a/net/mac80211/driver-ops.c
+++ b/net/mac80211/driver-ops.c
@@ -311,6 +311,18 @@ int drv_assign_vif_chanctx(struct ieee80211_local *local,
        might_sleep();
        lockdep_assert_wiphy(local->hw.wiphy);
 
+       /*
+        * We should perhaps push emulate chanctx down and only
+        * make it call ->config() when the chanctx is actually
+        * assigned here (and unassigned below), but that's yet
+        * another change to all drivers to add assign/unassign
+        * emulation callbacks. Maybe later.
+        */
+       if (sdata->vif.type == NL80211_IFTYPE_MONITOR &&
+           local->emulate_chanctx &&
+           !ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
+               return 0;
+
        if (!check_sdata_in_driver(sdata))
                return -EIO;
 
@@ -338,6 +350,11 @@ void drv_unassign_vif_chanctx(struct ieee80211_local *local,
        might_sleep();
        lockdep_assert_wiphy(local->hw.wiphy);
 
+       if (sdata->vif.type == NL80211_IFTYPE_MONITOR &&
+           local->emulate_chanctx &&
+           !ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
+               return;
+
        if (!check_sdata_in_driver(sdata))
                return;
 

diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c
index 0c54554bf761bf8e3cfa3fa72667f702eb83c99d..b935bb5d8ed1f7fa8a839961ec564f5b7a4b0984 100644 (file)
--- a/net/mac80211/iface.c
+++ b/net/mac80211/iface.c
@@ -1122,9 +1122,6 @@ int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
        struct ieee80211_sub_if_data *sdata;
        int ret;
 
-       if (!ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
-               return 0;
-
        ASSERT_RTNL();
        lockdep_assert_wiphy(local->hw.wiphy);
 
@@ -1146,11 +1143,13 @@ int ieee80211_add_virtual_monitor(struct ieee80211_local *local)
 
        ieee80211_set_default_queues(sdata);
 
-       ret = drv_add_interface(local, sdata);
-       if (WARN_ON(ret)) {
-               /* ok .. stupid driver, it asked for this! */
-               kfree(sdata);
-               return ret;
+       if (ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF)) {
+               ret = drv_add_interface(local, sdata);
+               if (WARN_ON(ret)) {
+                       /* ok .. stupid driver, it asked for this! */
+                       kfree(sdata);
+                       return ret;
+               }
        }
 
        set_bit(SDATA_STATE_RUNNING, &sdata->state);
@@ -1188,9 +1187,6 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
 {
        struct ieee80211_sub_if_data *sdata;
 
-       if (!ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
-               return;
-
        ASSERT_RTNL();
        lockdep_assert_wiphy(local->hw.wiphy);
 
@@ -1210,7 +1206,8 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local)
 
        ieee80211_link_release_channel(&sdata->deflink);
 
-       drv_remove_interface(local, sdata);
+       if (ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF))
+               drv_remove_interface(local, sdata);
 
        kfree(sdata);
 }

diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 283bfc99417e57dd65ed713a42991a2362bfff81..963ed75deb76593dedbeac8d422555dce54c60db 100644 (file)
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1843,7 +1843,7 @@ int ieee80211_reconfig(struct ieee80211_local *local)
 
        /* add interfaces */
        sdata = wiphy_dereference(local->hw.wiphy, local->monitor_sdata);
-       if (sdata) {
+       if (sdata && ieee80211_hw_check(&local->hw, WANT_MONITOR_VIF)) {
                /* in HW restart it exists already */
                WARN_ON(local->resuming);
                res = drv_add_interface(local, sdata);