wifi: mac80211: add a driver callback to check active_links

During ieee80211_set_active_links() we do (among the others):
1. Call drv_change_vif_links() with both old_active and new_active
2. Unassign the chanctx for the removed link(s) (if any)
3. Assign chanctx to the added link(s) (if any)
4. Call drv_change_vif_links() with the new_active links bitmap

The problem here is that during step #1 the driver doesn't know whether
we will activate multiple links simultaneously or are just doing a link
switch, so it can't check there if multiple links are supported/enabled.
(Some of the drivers might enable/disable this option dynamically)

And during step #3, in which the driver already knows that,
returning an error code (for example when multiple links are not
supported or disabled), will cause a warning, and we will still complete
the transition to the new_active links.
(It is hard to undo things in that stage, since we released channels etc.)

Therefore add a driver callback to check if the desired new_active links
will be supported by the driver or not. This callback will be called
in the beginning of ieee80211_set_active_links() so we won't do anything
before we are sure it is supported.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Reviewed-by: Gregory Greenman <gregory.greenman@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Link: https://msgid.link/20231220133549.64c4d70b33b8.I79708619be76b8ecd4ef3975205b8f903e24a2cd@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 46cc4443021695769fb8af0faadcadbcd030f117..d400fe2e8668d2cb70b22f0c5c70378bbdb78c01 100644 (file)
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -4272,6 +4272,8 @@ struct ieee80211_prep_tx_info {
  *     disable background CAC/radar detection.
  * @net_fill_forward_path: Called from .ndo_fill_forward_path in order to
  *     resolve a path for hardware flow offloading
+ * @can_activate_links: Checks if a specific active_links bitmap is
+ *     supported by the driver.
  * @change_vif_links: Change the valid links on an interface, note that while
  *     removing the old link information is still valid (link_conf pointer),
  *     but may immediately disappear after the function returns. The old or
@@ -4652,6 +4654,9 @@ struct ieee80211_ops {
                                     struct ieee80211_sta *sta,
                                     struct net_device_path_ctx *ctx,
                                     struct net_device_path *path);
+       bool (*can_activate_links)(struct ieee80211_hw *hw,
+                                  struct ieee80211_vif *vif,
+                                  u16 active_links);
        int (*change_vif_links)(struct ieee80211_hw *hw,
                                struct ieee80211_vif *vif,
                                u16 old_links, u16 new_links,

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index e9219f9278750d75db4211f8dfba24315cc6ac56..eb482fb8c3afe5b513d7cbc85eabb11cd3155aae 100644 (file)
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1666,6 +1666,26 @@ static inline int drv_net_setup_tc(struct ieee80211_local *local,
        return ret;
 }
 
+static inline bool drv_can_activate_links(struct ieee80211_local *local,
+                                         struct ieee80211_sub_if_data *sdata,
+                                         u16 active_links)
+{
+       bool ret = true;
+
+       lockdep_assert_wiphy(local->hw.wiphy);
+
+       if (!check_sdata_in_driver(sdata))
+               return false;
+
+       trace_drv_can_activate_links(local, sdata, active_links);
+       if (local->ops->can_activate_links)
+               ret = local->ops->can_activate_links(&local->hw, &sdata->vif,
+                                                    active_links);
+       trace_drv_return_bool(local, ret);
+
+       return ret;
+}
+
 int drv_change_vif_links(struct ieee80211_local *local,
                         struct ieee80211_sub_if_data *sdata,
                         u16 old_links, u16 new_links,

diff --git a/net/mac80211/link.c b/net/mac80211/link.c
index bf7bd880d062394251165fbc2ad279b6d720164c..d4f86955afa6d01359f336e4086e0a21af509e0d 100644 (file)
--- a/net/mac80211/link.c
+++ b/net/mac80211/link.c
@@ -444,6 +444,9 @@ int ieee80211_set_active_links(struct ieee80211_vif *vif, u16 active_links)
 
        lockdep_assert_wiphy(local->hw.wiphy);
 
+       if (!drv_can_activate_links(local, sdata, active_links))
+               return -EINVAL;
+
        old_active = sdata->vif.active_links;
        if (old_active & active_links) {
                /*

diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h
index 032718d5b298c3467ab0f2420a1f1d6ad980d6a2..06835ed4c44f136ed2cbcad79c1235688c7b7ed3 100644 (file)
--- a/net/mac80211/trace.h
+++ b/net/mac80211/trace.h
@@ -2512,6 +2512,31 @@ TRACE_EVENT(drv_net_setup_tc,
        )
 );
 
+TRACE_EVENT(drv_can_activate_links,
+       TP_PROTO(struct ieee80211_local *local,
+                struct ieee80211_sub_if_data *sdata,
+                u16 active_links),
+
+       TP_ARGS(local, sdata, active_links),
+
+       TP_STRUCT__entry(
+               LOCAL_ENTRY
+               VIF_ENTRY
+               __field(u16, active_links)
+       ),
+
+       TP_fast_assign(
+               LOCAL_ASSIGN;
+               VIF_ASSIGN;
+               __entry->active_links = active_links;
+       ),
+
+       TP_printk(
+               LOCAL_PR_FMT VIF_PR_FMT " requested active_links:0x%04x\n",
+               LOCAL_PR_ARG, VIF_PR_ARG, __entry->active_links
+       )
+);
+
 TRACE_EVENT(drv_change_vif_links,
        TP_PROTO(struct ieee80211_local *local,
                 struct ieee80211_sub_if_data *sdata,