mwifiex: replace ra_list_curr by list rotation.

After a packet is successfully transmitted, ra list is rotated, so the ra
next to the one transmitted, will be the first in the list. This way we
pick the ra' in a round robin fashion. This significantly simplifies
iteration in  mwifiex_wmm_get_highest_priolist_ptr to a call to
list_for_each_entry.
List rotation is done via list_move, where the head itself is temporarily
removed and then re-inserted after the item just transferred.

Signed-off-by: Andreas Fenkart <andreas.fenkart@streamunlimited.com>
Acked-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

4 files changed, 40 insertions, 69 deletions

diff --git a/drivers/net/wireless/mwifiex/11n_aggr.c b/drivers/net/wireless/mwifiex/11n_aggr.c
index af8fe6352eed..c6d74518aaab 100644
--- a/drivers/net/wireless/mwifiex/11n_aggr.c
+++ b/drivers/net/wireless/mwifiex/11n_aggr.c
@@ -296,19 +296,13 @@ mwifiex_11n_aggregate_pkt(struct mwifiex_private *priv,
                 break;
         }
         if (ret != -EBUSY) {
-                spin_lock_irqsave(&priv->wmm.ra_list_spinlock, ra_list_flags);
-                if (mwifiex_is_ralist_valid(priv, pra_list, ptrindex)) {
-                        priv->wmm.packets_out[ptrindex]++;
-                        priv->wmm.tid_tbl_ptr[ptrindex].ra_list_curr = pra_list;
-                }
+                mwifiex_rotate_priolists(priv, pra_list, ptrindex);
                 /* Now bss_prio_cur pointer points to next node */
                 adapter->bss_prio_tbl[priv->bss_priority].bss_prio_cur =
                         list_first_entry(
                                 &adapter->bss_prio_tbl[priv->bss_priority]
                                 .bss_prio_cur->list,
                                 struct mwifiex_bss_prio_node, list);
-                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
-                                       ra_list_flags);
         }
 
         return 0;
diff --git a/drivers/net/wireless/mwifiex/main.h b/drivers/net/wireless/mwifiex/main.h
index b7484efc9443..4ef67fca06d3 100644
--- a/drivers/net/wireless/mwifiex/main.h
+++ b/drivers/net/wireless/mwifiex/main.h
@@ -213,7 +213,6 @@ struct mwifiex_ra_list_tbl {
 
 struct mwifiex_tid_tbl {
         struct list_head ra_list;
-        struct mwifiex_ra_list_tbl *ra_list_curr;
 };
 
 #define WMM_HIGHEST_PRIORITY            7
diff --git a/drivers/net/wireless/mwifiex/wmm.c b/drivers/net/wireless/mwifiex/wmm.c
index 2cc81ba590e3..b48e03cde23f 100644
--- a/drivers/net/wireless/mwifiex/wmm.c
+++ b/drivers/net/wireless/mwifiex/wmm.c
@@ -191,9 +191,6 @@ mwifiex_ralist_add(struct mwifiex_private *priv, u8 *ra)
                 }
                 list_add_tail(&ra_list->list,
                               &priv->wmm.tid_tbl_ptr[i].ra_list);
-
-                if (!priv->wmm.tid_tbl_ptr[i].ra_list_curr)
-                        priv->wmm.tid_tbl_ptr[i].ra_list_curr = ra_list;
         }
 }
 
@@ -424,7 +421,6 @@ mwifiex_wmm_init(struct mwifiex_adapter *adapter)
                         priv->aggr_prio_tbl[i].amsdu = tos_to_tid_inv[i];
                         priv->aggr_prio_tbl[i].ampdu_ap = tos_to_tid_inv[i];
                         priv->aggr_prio_tbl[i].ampdu_user = tos_to_tid_inv[i];
-                        priv->wmm.tid_tbl_ptr[i].ra_list_curr = NULL;
                 }
 
                 priv->aggr_prio_tbl[6].amsdu
@@ -530,8 +526,6 @@ static void mwifiex_wmm_delete_all_ralist(struct mwifiex_private *priv)
                 }
 
                 INIT_LIST_HEAD(&priv->wmm.tid_tbl_ptr[i].ra_list);
-
-                priv->wmm.tid_tbl_ptr[i].ra_list_curr = NULL;
         }
 }
 
@@ -883,7 +877,7 @@ mwifiex_wmm_get_highest_priolist_ptr(struct mwifiex_adapter *adapter,
                                      struct mwifiex_private **priv, int *tid)
 {
         struct mwifiex_private *priv_tmp;
-        struct mwifiex_ra_list_tbl *ptr, *head;
+        struct mwifiex_ra_list_tbl *ptr;
         struct mwifiex_bss_prio_node *bssprio_node, *bssprio_head;
         struct mwifiex_tid_tbl *tid_ptr;
         atomic_t *hqp;
@@ -926,51 +920,15 @@ mwifiex_wmm_get_highest_priolist_ptr(struct mwifiex_adapter *adapter,
                                 tid_ptr = &(priv_tmp)->wmm.
                                         tid_tbl_ptr[tos_to_tid[i]];
 
-                                /* For non-STA ra_list_curr may be NULL */
-                                if (!tid_ptr->ra_list_curr)
-                                        goto skip_wmm_queue;
-
-                                if (list_empty(&tid_ptr->ra_list))
-                                        goto skip_wmm_queue;
-
-                                /*
-                                 * Always choose the next ra we transmitted
-                                 * last time, this way we pick the ra's in
-                                 * round robin fashion.
-                                 */
-                                ptr = list_first_entry(
-                                                &tid_ptr->ra_list_curr->list,
-                                                struct mwifiex_ra_list_tbl,
-                                                list);
+                                /* iterate over receiver addresses */
+                                list_for_each_entry(ptr, &tid_ptr->ra_list,
+                                                    list) {
 
-                                head = ptr;
-                                if (ptr == (struct mwifiex_ra_list_tbl *)
-                                                &tid_ptr->ra_list) {
-                                        /* Get next ra */
-                                        ptr = list_first_entry(&ptr->list,
-                                            struct mwifiex_ra_list_tbl, list);
-                                        head = ptr;
-                                }
-
-                                do {
                                         if (!skb_queue_empty(&ptr->skb_head))
                                                 /* holds both locks */
                                                 goto found;
+                                }
 
-                                        /* Get next ra */
-                                        ptr = list_first_entry(&ptr->list,
-                                                 struct mwifiex_ra_list_tbl,
-                                                 list);
-                                        if (ptr ==
-                                            (struct mwifiex_ra_list_tbl *)
-                                            &tid_ptr->ra_list)
-                                                ptr = list_first_entry(
-                                                    &ptr->list,
-                                                    struct mwifiex_ra_list_tbl,
-                                                    list);
-                                } while (ptr != head);
-
-skip_wmm_queue:
                                 spin_unlock_irqrestore(&priv_tmp->wmm.
                                                        ra_list_spinlock,
                                                        flags_ra);
@@ -1013,6 +971,35 @@ found:
         return ptr;
 }
 
+/* This functions rotates ra lists so packets are picked in round robin
+ * fashion.
+ *
+ * After a packet is successfully transmitted, rotate the ra list, so the ra
+ * next to the one transmitted, will come first in the list. This way we pick
+ * the ra in a round robin fashion.
+ *
+ * Function also increments wmm.packets_out counter.
+ */
+void mwifiex_rotate_priolists(struct mwifiex_private *priv,
+                                 struct mwifiex_ra_list_tbl *ra,
+                                 int tid)
+{
+        struct mwifiex_tid_tbl *tid_ptr = &priv->wmm.tid_tbl_ptr[tid];
+        unsigned long flags;
+
+        spin_lock_irqsave(&priv->wmm.ra_list_spinlock, flags);
+        if (mwifiex_is_ralist_valid(priv, ra, tid)) {
+                priv->wmm.packets_out[tid]++;
+                /*
+                 * dirty trick: we remove 'head' temporarily and reinsert it
+                 * after curr bss node. imagine list to stay fixed while only
+                 * head is moved
+                 */
+                list_move(&tid_ptr->ra_list, &ra->list);
+        }
+        spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock, flags);
+}
+
 /*
  * This function checks if 11n aggregation is possible.
  */
@@ -1099,11 +1086,7 @@ mwifiex_send_single_packet(struct mwifiex_private *priv,
                 spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
                                        ra_list_flags);
         } else {
-                spin_lock_irqsave(&priv->wmm.ra_list_spinlock, ra_list_flags);
-                if (mwifiex_is_ralist_valid(priv, ptr, ptr_index)) {
-                        priv->wmm.packets_out[ptr_index]++;
-                        priv->wmm.tid_tbl_ptr[ptr_index].ra_list_curr = ptr;
-                }
+                mwifiex_rotate_priolists(priv, ptr, ptr_index);
                 adapter->bss_prio_tbl[priv->bss_priority].bss_prio_cur =
                         list_first_entry(
                                 &adapter->bss_prio_tbl[priv->bss_priority]
@@ -1111,8 +1094,6 @@ mwifiex_send_single_packet(struct mwifiex_private *priv,
                                 struct mwifiex_bss_prio_node,
                                 list);
                 atomic_dec(&priv->wmm.tx_pkts_queued);
-                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
-                                       ra_list_flags);
         }
 }
 
@@ -1216,11 +1197,7 @@ mwifiex_send_processed_packet(struct mwifiex_private *priv,
                 break;
         }
         if (ret != -EBUSY) {
-                spin_lock_irqsave(&priv->wmm.ra_list_spinlock, ra_list_flags);
-                if (mwifiex_is_ralist_valid(priv, ptr, ptr_index)) {
-                        priv->wmm.packets_out[ptr_index]++;
-                        priv->wmm.tid_tbl_ptr[ptr_index].ra_list_curr = ptr;
-                }
+                mwifiex_rotate_priolists(priv, ptr, ptr_index);
                 adapter->bss_prio_tbl[priv->bss_priority].bss_prio_cur =
                         list_first_entry(
                                 &adapter->bss_prio_tbl[priv->bss_priority]
@@ -1228,8 +1205,6 @@ mwifiex_send_processed_packet(struct mwifiex_private *priv,
                                 struct mwifiex_bss_prio_node,
                                 list);
                 atomic_dec(&priv->wmm.tx_pkts_queued);
-                spin_unlock_irqrestore(&priv->wmm.ra_list_spinlock,
-                                       ra_list_flags);
         }
 }
 
diff --git a/drivers/net/wireless/mwifiex/wmm.h b/drivers/net/wireless/mwifiex/wmm.h
index b92f39d8963b..644d6e0c51cc 100644
--- a/drivers/net/wireless/mwifiex/wmm.h
+++ b/drivers/net/wireless/mwifiex/wmm.h
@@ -85,6 +85,9 @@ mwifiex_wmm_is_ra_list_empty(struct list_head *ra_list_hhead)
 void mwifiex_wmm_add_buf_txqueue(struct mwifiex_private *priv,
                                         struct sk_buff *skb);
 void mwifiex_ralist_add(struct mwifiex_private *priv, u8 *ra);
+void mwifiex_rotate_priolists(struct mwifiex_private *priv,
+                              struct mwifiex_ra_list_tbl *ra,
+                              int tid);
 
 int mwifiex_wmm_lists_empty(struct mwifiex_adapter *adapter);
 void mwifiex_wmm_process_tx(struct mwifiex_adapter *adapter);