mac80211: prepare sta handling for MLO support

Currently in mac80211 each STA object is represented
using sta_info datastructure with the associated
STA specific information and drivers access ieee80211_sta
part of it.

With MLO (Multi Link Operation) support being added
in 802.11be standard, though the association is logically
with a single Multi Link capable STA, at the physical level
communication can happen via different advertised
links (uniquely identified by Channel, operating class,
BSSID) and hence the need to handle multiple link
STA parameters within a composite sta_info object
called the MLD STA. The different link STA part of
MLD STA are identified using the link address which can
be same or different as the MLD STA address and unique
link id based on the link vif.

To support extension of such a model, the sta_info
datastructure is modified to hold multiple link STA
objects with link specific params currently within
sta_info moved to this new structure. Similarly this is
done for ieee80211_sta as well which will be accessed
within mac80211 as well as by drivers, hence trivial
driver changes are expected to support this.

For current non MLO supported drivers, only one link STA
is present and link information is accessed via 'deflink'
member.

For MLO drivers, we still need to define the APIs etc. to
get the correct link ID and access the correct part of
the station info.

Currently in mac80211, all link STA info are accessed directly
via deflink. These will be updated to access via link pointers
indexed by link id with MLO support patches, with link id
being 0 for non MLO supported cases.

Except for couple of macro related changes, below spatch takes
care of updating mac80211 and driver code to access to the
link STA info via deflink.

  @ieee80211_sta@
  struct ieee80211_sta *s;
  struct sta_info *si;
  identifier var = {supp_rates, ht_cap, vht_cap, he_cap, he_6ghz_capa, eht_cap, rx_nss, bandwidth, txpwr};
  @@

  (
    s->
  -    var
  +    deflink.var
  |
   si->sta.
  -    var
  +    deflink.var
  )

  @sta_info@
  struct sta_info *si;
  identifier var = {gtk, pcpu_rx_stats, rx_stats, rx_stats_avg, status_stats, tx_stats, cur_max_bandwidth};
  @@

  (
    si->
  -    var
  +    deflink.var
  )

Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Link: https://lore.kernel.org/r/1649086883-13246-1-git-send-email-quic_srirrama@quicinc.com
[remove MLO-drivers notes from commit message, not clear yet; run spatch]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 96 insertions, 59 deletions

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 379fd367197f..35c390bedfba 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -484,6 +484,86 @@ struct ieee80211_fragment_cache {
 #define STA_SLOW_THRESHOLD 6000 /* 6 Mbps */
 
 /**
+ * struct link_sta_info - Link STA information
+ * All link specific sta info are stored here for reference. This can be
+ * a single entry for non-MLD STA or multiple entries for MLD STA
+ * @addr: Link MAC address - Can be same as MLD STA mac address and is always
+ *	same for non-MLD STA. This is used as key for searching link STA
+ * @link_id: Link ID uniquely identifying the link STA. This is 0 for non-MLD
+ *	and set to the corresponding vif LinkId for MLD STA
+ * @sta: Points to the STA info
+ * @gtk: group keys negotiated with this station, if any
+ * @tx_stats: TX statistics
+ * @tx_stats.packets: # of packets transmitted
+ * @tx_stats.bytes: # of bytes in all packets transmitted
+ * @tx_stats.last_rate: last TX rate
+ * @tx_stats.msdu: # of transmitted MSDUs per TID
+ * @rx_stats: RX statistics
+ * @rx_stats_avg: averaged RX statistics
+ * @rx_stats_avg.signal: averaged signal
+ * @rx_stats_avg.chain_signal: averaged per-chain signal
+ * @pcpu_rx_stats: per-CPU RX statistics, assigned only if the driver needs
+ *	this (by advertising the USES_RSS hw flag)
+ * @status_stats: TX status statistics
+ * @status_stats.filtered: # of filtered frames
+ * @status_stats.retry_failed: # of frames that failed after retry
+ * @status_stats.retry_count: # of retries attempted
+ * @status_stats.lost_packets: # of lost packets
+ * @status_stats.last_pkt_time: timestamp of last ACKed packet
+ * @status_stats.msdu_retries: # of MSDU retries
+ * @status_stats.msdu_failed: # of failed MSDUs
+ * @status_stats.last_ack: last ack timestamp (jiffies)
+ * @status_stats.last_ack_signal: last ACK signal
+ * @status_stats.ack_signal_filled: last ACK signal validity
+ * @status_stats.avg_ack_signal: average ACK signal
+ * TODO Move other link params from sta_info as required for MLD operation
+ */
+struct link_sta_info {
+	u8 addr[ETH_ALEN];
+	u8 link_id;
+
+	/* TODO rhash head/node for finding link_sta based on addr */
+
+	struct sta_info *sta;
+	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS +
+					NUM_DEFAULT_MGMT_KEYS +
+					NUM_DEFAULT_BEACON_KEYS];
+	struct ieee80211_sta_rx_stats __percpu *pcpu_rx_stats;
+
+	/* Updated from RX path only, no locking requirements */
+	struct ieee80211_sta_rx_stats rx_stats;
+	struct {
+		struct ewma_signal signal;
+		struct ewma_signal chain_signal[IEEE80211_MAX_CHAINS];
+	} rx_stats_avg;
+
+	/* Updated from TX status path only, no locking requirements */
+	struct {
+		unsigned long filtered;
+		unsigned long retry_failed, retry_count;
+		unsigned int lost_packets;
+		unsigned long last_pkt_time;
+		u64 msdu_retries[IEEE80211_NUM_TIDS + 1];
+		u64 msdu_failed[IEEE80211_NUM_TIDS + 1];
+		unsigned long last_ack;
+		s8 last_ack_signal;
+		bool ack_signal_filled;
+		struct ewma_avg_signal avg_ack_signal;
+	} status_stats;
+
+	/* Updated from TX path only, no locking requirements */
+	struct {
+		u64 packets[IEEE80211_NUM_ACS];
+		u64 bytes[IEEE80211_NUM_ACS];
+		struct ieee80211_tx_rate last_rate;
+		struct rate_info last_rate_info;
+		u64 msdu[IEEE80211_NUM_TIDS + 1];
+	} tx_stats;
+
+	enum ieee80211_sta_rx_bandwidth cur_max_bandwidth;
+};
+
+/**
  * struct sta_info - STA information
  *
  * This structure collects information about a station that
@@ -498,7 +578,6 @@ struct ieee80211_fragment_cache {
  * @sdata: virtual interface this station belongs to
  * @ptk: peer keys negotiated with this station, if any
  * @ptk_idx: last installed peer key index
- * @gtk: group keys negotiated with this station, if any
  * @rate_ctrl: rate control algorithm reference
  * @rate_ctrl_lock: spinlock used to protect rate control data
  *	(data inside the algorithm, so serializes calls there)
@@ -544,30 +623,19 @@ struct ieee80211_fragment_cache {
  * @fast_rx: RX fastpath information
  * @tdls_chandef: a TDLS peer can have a wider chandef that is compatible to
  *	the BSS one.
- * @tx_stats: TX statistics
- * @tx_stats.packets: # of packets transmitted
- * @tx_stats.bytes: # of bytes in all packets transmitted
- * @tx_stats.last_rate: last TX rate
- * @tx_stats.msdu: # of transmitted MSDUs per TID
- * @rx_stats: RX statistics
- * @rx_stats_avg: averaged RX statistics
- * @rx_stats_avg.signal: averaged signal
- * @rx_stats_avg.chain_signal: averaged per-chain signal
- * @pcpu_rx_stats: per-CPU RX statistics, assigned only if the driver needs
- *	this (by advertising the USES_RSS hw flag)
- * @status_stats: TX status statistics
- * @status_stats.filtered: # of filtered frames
- * @status_stats.retry_failed: # of frames that failed after retry
- * @status_stats.retry_count: # of retries attempted
- * @status_stats.lost_packets: # of lost packets
- * @status_stats.last_pkt_time: timestamp of last ACKed packet
- * @status_stats.msdu_retries: # of MSDU retries
- * @status_stats.msdu_failed: # of failed MSDUs
- * @status_stats.last_ack: last ack timestamp (jiffies)
- * @status_stats.last_ack_signal: last ACK signal
- * @status_stats.ack_signal_filled: last ACK signal validity
- * @status_stats.avg_ack_signal: average ACK signal
  * @frags: fragment cache
+ * @multi_link_sta: Identifies if this sta is a MLD STA or regular STA
+ * @deflink: This is the default link STA information, for non MLO STA all link
+ *	specific STA information is accessed through @deflink or through
+ *	link[0] which points to address of @deflink. For MLO Link STA
+ *	the first added link STA will point to deflink.
+ * @link: reference to Link Sta entries. For Non MLO STA, except 1st link,
+ *	i.e link[0] all links would be assigned to NULL by default and
+ *	would access link information via @deflink or link[0]. For MLO
+ *	STA, first link STA being added will point its link pointer to
+ *	@deflink address and remaining would be allocated and the address
+ *	would be assigned to link[link_id] where link_id is the id assigned
+ *	by the AP.
  */
 struct sta_info {
 	/* General information, mostly static */
@@ -577,9 +645,6 @@ struct sta_info {
 	u8 addr[ETH_ALEN];
 	struct ieee80211_local *local;
 	struct ieee80211_sub_if_data *sdata;
-	struct ieee80211_key __rcu *gtk[NUM_DEFAULT_KEYS +
-					NUM_DEFAULT_MGMT_KEYS +
-					NUM_DEFAULT_BEACON_KEYS];
 	struct ieee80211_key __rcu *ptk[NUM_DEFAULT_KEYS];
 	u8 ptk_idx;
 	struct rate_control_ref *rate_ctrl;
@@ -589,7 +654,6 @@ struct sta_info {
 
 	struct ieee80211_fast_tx __rcu *fast_tx;
 	struct ieee80211_fast_rx __rcu *fast_rx;
-	struct ieee80211_sta_rx_stats __percpu *pcpu_rx_stats;
 
 #ifdef CONFIG_MAC80211_MESH
 	struct mesh_sta *mesh;
@@ -619,38 +683,9 @@ struct sta_info {
 	u64 assoc_at;
 	long last_connected;
 
-	/* Updated from RX path only, no locking requirements */
-	struct ieee80211_sta_rx_stats rx_stats;
-	struct {
-		struct ewma_signal signal;
-		struct ewma_signal chain_signal[IEEE80211_MAX_CHAINS];
-	} rx_stats_avg;
-
 	/* Plus 1 for non-QoS frames */
 	__le16 last_seq_ctrl[IEEE80211_NUM_TIDS + 1];
 
-	/* Updated from TX status path only, no locking requirements */
-	struct {
-		unsigned long filtered;
-		unsigned long retry_failed, retry_count;
-		unsigned int lost_packets;
-		unsigned long last_pkt_time;
-		u64 msdu_retries[IEEE80211_NUM_TIDS + 1];
-		u64 msdu_failed[IEEE80211_NUM_TIDS + 1];
-		unsigned long last_ack;
-		s8 last_ack_signal;
-		bool ack_signal_filled;
-		struct ewma_avg_signal avg_ack_signal;
-	} status_stats;
-
-	/* Updated from TX path only, no locking requirements */
-	struct {
-		u64 packets[IEEE80211_NUM_ACS];
-		u64 bytes[IEEE80211_NUM_ACS];
-		struct ieee80211_tx_rate last_rate;
-		struct rate_info last_rate_info;
-		u64 msdu[IEEE80211_NUM_TIDS + 1];
-	} tx_stats;
 	u16 tid_seq[IEEE80211_QOS_CTL_TID_MASK + 1];
 
 	struct airtime_info airtime[IEEE80211_NUM_ACS];
@@ -664,8 +699,6 @@ struct sta_info {
 	struct dentry *debugfs_dir;
 #endif
 
-	enum ieee80211_sta_rx_bandwidth cur_max_bandwidth;
-
 	enum ieee80211_smps_mode known_smps_mode;
 	const struct ieee80211_cipher_scheme *cipher_scheme;
 
@@ -677,6 +710,10 @@ struct sta_info {
 
 	struct ieee80211_fragment_cache frags;
 
+	bool multi_link_sta;
+	struct link_sta_info deflink;
+	struct link_sta_info *link[MAX_STA_LINKS];
+
 	/* keep last! */
 	struct ieee80211_sta sta;
 };