mac80211: clean up sta_info and document locking

This patch cleans up the sta_info struct and documents how
each set of variables is locked. Notably, flags locking is
completely missing. It also adds kernel-doc for some (but
not all yet) members of the struct.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 82 insertions, 53 deletions

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 3f788228eeff..fb5411d01f82 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -139,84 +139,113 @@ struct sta_ampdu_mlme {
 #define STA_INFO_PIN_STAT_PINNED        1
 #define STA_INFO_PIN_STAT_DESTROY       2
 
-
+/**
+ * struct sta_info - STA information
+ *
+ * This structure collects information about a station that
+ * mac80211 is communicating with.
+ *
+ * @list: global linked list entry
+ * @hnext: hash table linked list pointer
+ * @local: pointer to the global information
+ * @addr: MAC address of this STA
+ * @aid: STA's unique AID (1..2007, 0 = not assigned yet),
+ *      only used in AP (and IBSS?) mode
+ * @flags: STA flags, see &enum ieee80211_sta_info_flags
+ * @ps_tx_buf: buffer of frames to transmit to this station
+ *      when it leaves power saving state
+ * @tx_filtered: buffer of frames we already tried to transmit
+ *      but were filtered by hardware due to STA having entered
+ *      power saving state
+ * @rx_packets: Number of MSDUs received from this STA
+ * @rx_bytes: Number of bytes received from this STA
+ * @supp_rates: Bitmap of supported rates (per band)
+ * @ht_info: HT capabilities of this STA
+ */
 struct sta_info {
+        /* General information, mostly static */
         struct list_head list;
-        struct sta_info *hnext; /* next entry in hash table list */
-
+        struct sta_info *hnext;
         struct ieee80211_local *local;
-
-        u8 addr[ETH_ALEN];
-        u16 aid; /* STA's unique AID (1..2007), 0 = not yet assigned */
-        u32 flags; /* WLAN_STA_ */
-
-        struct sk_buff_head ps_tx_buf; /* buffer of TX frames for station in
-                                        * power saving state */
-        struct sk_buff_head tx_filtered; /* buffer of TX frames that were
-                                          * already given to low-level driver,
-                                          * but were filtered */
-        unsigned long rx_packets, tx_packets; /* number of RX/TX MSDUs */
-        unsigned long rx_bytes, tx_bytes;
-        unsigned long tx_retry_failed, tx_retry_count;
-        unsigned long tx_filtered_count;
-        /* moving percentage of failed MSDUs */
-        unsigned int fail_avg;
-
-        unsigned int wep_weak_iv_count; /* number of RX frames with weak IV */
-
-        unsigned long last_rx;
-        /* bitmap of supported rates per band */
-        u64 supp_rates[IEEE80211_NUM_BANDS];
-        int txrate_idx;
-        /* last rates used to send a frame to this STA */
-        int last_txrate_idx, last_nonerp_txrate_idx;
-
-        /* sub_if_data this sta belongs to */
         struct ieee80211_sub_if_data *sdata;
-
         struct ieee80211_key *key;
-
-        u32 tx_num_consecutive_failures;
-        u32 tx_num_mpdu_ok;
-        u32 tx_num_mpdu_fail;
-
         struct rate_control_ref *rate_ctrl;
         void *rate_ctrl_priv;
+        struct ieee80211_ht_info ht_info;
+        u64 supp_rates[IEEE80211_NUM_BANDS];
+        u8 addr[ETH_ALEN];
+        u16 aid;
+        u16 listen_interval;
 
-        /* last received seq/frag number from this STA (per RX queue) */
-        __le16 last_seq_ctrl[NUM_RX_DATA_QUEUES];
+        /*
+         * for use by the internal lifetime management,
+         * see __sta_info_unlink
+         */
+        u8 pin_status;
+
+        /* frequently updated information, needs locking? */
+        u32 flags;
+
+        /*
+         * STA powersave frame queues, no more than the internal
+         * locking required.
+         */
+        struct sk_buff_head ps_tx_buf;
+        struct sk_buff_head tx_filtered;
+
+        /* Updated from RX path only, no locking requirements */
+        unsigned long rx_packets, rx_bytes;
+        unsigned long wep_weak_iv_count;
+        unsigned long last_rx;
         unsigned long num_duplicates; /* number of duplicate frames received
                                        * from this STA */
-        unsigned long tx_fragments; /* number of transmitted MPDUs */
         unsigned long rx_fragments; /* number of received MPDUs */
         unsigned long rx_dropped; /* number of dropped MPDUs from this STA */
-
         int last_rssi; /* RSSI of last received frame from this STA */
         int last_signal; /* signal of last received frame from this STA */
         int last_noise; /* noise of last received frame from this STA */
-        int channel_use;
-        int channel_use_raw;
-
+        /* last received seq/frag number from this STA (per RX queue) */
+        __le16 last_seq_ctrl[NUM_RX_DATA_QUEUES];
 #ifdef CONFIG_MAC80211_DEBUG_COUNTERS
         unsigned int wme_rx_queue[NUM_RX_DATA_QUEUES];
+#endif
+
+        /* Updated from TX status path only, no locking requirements */
+        unsigned long tx_filtered_count;
+        unsigned long tx_retry_failed, tx_retry_count;
+        /* TODO: update in generic code not rate control? */
+        u32 tx_num_consecutive_failures;
+        u32 tx_num_mpdu_ok;
+        u32 tx_num_mpdu_fail;
+        /* moving percentage of failed MSDUs */
+        unsigned int fail_avg;
+
+        /* Updated from TX path only, no locking requirements */
+        unsigned long tx_packets; /* number of RX/TX MSDUs */
+        unsigned long tx_bytes;
+        unsigned long tx_fragments; /* number of transmitted MPDUs */
+        int txrate_idx;
+        int last_txrate_idx;
+#ifdef CONFIG_MAC80211_DEBUG_COUNTERS
         unsigned int wme_tx_queue[NUM_RX_DATA_QUEUES];
-#endif /* CONFIG_MAC80211_DEBUG_COUNTERS */
+#endif
 
-        u16 listen_interval;
+        /* Debug counters, no locking doesn't matter */
+        int channel_use;
+        int channel_use_raw;
 
         /*
-         * for use by the internal lifetime management,
-         * see __sta_info_unlink
+         * Aggregation information, comes with own locking.
          */
-        u8 pin_status;
-
-        struct ieee80211_ht_info ht_info; /* 802.11n HT capabilities
-                                             of this STA */
         struct sta_ampdu_mlme ampdu_mlme;
-        u8 timer_to_tid[STA_TID_NUM];   /* convert timer id to tid */
+        u8 timer_to_tid[STA_TID_NUM];   /* identity mapping to ID timers */
         u8 tid_to_tx_q[STA_TID_NUM];    /* map tid to tx queue */
+
 #ifdef CONFIG_MAC80211_MESH
-        /* mesh peer link attributes */
+        /*
+         * Mesh peer link attributes
+         * TODO: move to a sub-structure that is referenced with pointer?
+         */
         __le16 llid;            /* Local link ID */
         __le16 plid;            /* Peer link ID */
         __le16 reason;          /* Buffer for cancel reason on HOLDING state */