iwlwifi: reuse page for notification packets

For notification packets and SKBs that fail to rx correctly, add
them back into the rx_free list so that the pages can be reused
later. This avoids allocating new rx pages unnecessarily.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 30 insertions, 24 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index 0d3886505205..ea1b9315f17c 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -769,7 +769,7 @@ void iwl_rx_handle(struct iwl_priv *priv)
                 IWL_DEBUG_RX(priv, "r = %d, i = %d\n", r, i);
 
         /* calculate total frames need to be restock after handling RX */
-        total_empty = r - priv->rxq.write_actual;
+        total_empty = r - rxq->write_actual;
         if (total_empty < 0)
                 total_empty += RX_QUEUE_SIZE;
 
@@ -841,25 +841,28 @@ void iwl_rx_handle(struct iwl_priv *priv)
                                 IWL_WARN(priv, "Claim null rxb?\n");
                 }
 
-                /* For now we just don't re-use anything.  We can tweak this
-                 * later to try and re-use notification packets and SKBs that
-                 * fail to Rx correctly */
+                /* Reuse the page if possible. For notification packets and
+                 * SKBs that fail to Rx correctly, add them back into the
+                 * rx_free list for reuse later. */
+                spin_lock_irqsave(&rxq->lock, flags);
                 if (rxb->page != NULL) {
-                        priv->alloc_rxb_page--;
-                        __free_pages(rxb->page, priv->hw_params.rx_page_order);
-                        rxb->page = NULL;
-                }
+                        rxb->page_dma = pci_map_page(priv->pci_dev, rxb->page,
+                                0, PAGE_SIZE << priv->hw_params.rx_page_order,
+                                PCI_DMA_FROMDEVICE);
+                        list_add_tail(&rxb->list, &rxq->rx_free);
+                        rxq->free_count++;
+                } else
+                        list_add_tail(&rxb->list, &rxq->rx_used);
 
-                spin_lock_irqsave(&rxq->lock, flags);
-                list_add_tail(&rxb->list, &priv->rxq.rx_used);
                 spin_unlock_irqrestore(&rxq->lock, flags);
+
                 i = (i + 1) & RX_QUEUE_MASK;
                 /* If there are a lot of unused frames,
                  * restock the Rx queue so ucode wont assert. */
                 if (fill_rx) {
                         count++;
                         if (count >= 8) {
-                                priv->rxq.read = i;
+                                rxq->read = i;
                                 iwl_rx_replenish_now(priv);
                                 count = 0;
                         }
@@ -867,7 +870,7 @@ void iwl_rx_handle(struct iwl_priv *priv)
         }
 
         /* Backtrack one entry */
-        priv->rxq.read = i;
+        rxq->read = i;
         if (fill_rx)
                 iwl_rx_replenish_now(priv);
         else
diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 8b08bdc10bc9..9a430eed34ad 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -1367,7 +1367,7 @@ static void iwl3945_rx_handle(struct iwl_priv *priv)
         i = rxq->read;
 
         /* calculate total frames need to be restock after handling RX */
-        total_empty = r - priv->rxq.write_actual;
+        total_empty = r - rxq->write_actual;
         if (total_empty < 0)
                 total_empty += RX_QUEUE_SIZE;
 
@@ -1438,25 +1438,28 @@ static void iwl3945_rx_handle(struct iwl_priv *priv)
                                 IWL_WARN(priv, "Claim null rxb?\n");
                 }
 
-                /* For now we just don't re-use anything.  We can tweak this
-                 * later to try and re-use notification packets and SKBs that
-                 * fail to Rx correctly */
+                /* Reuse the page if possible. For notification packets and
+                 * SKBs that fail to Rx correctly, add them back into the
+                 * rx_free list for reuse later. */
+                spin_lock_irqsave(&rxq->lock, flags);
                 if (rxb->page != NULL) {
-                        priv->alloc_rxb_page--;
-                        __free_pages(rxb->page, priv->hw_params.rx_page_order);
-                        rxb->page = NULL;
-                }
+                        rxb->page_dma = pci_map_page(priv->pci_dev, rxb->page,
+                                0, PAGE_SIZE << priv->hw_params.rx_page_order,
+                                PCI_DMA_FROMDEVICE);
+                        list_add_tail(&rxb->list, &rxq->rx_free);
+                        rxq->free_count++;
+                } else
+                        list_add_tail(&rxb->list, &rxq->rx_used);
 
-                spin_lock_irqsave(&rxq->lock, flags);
-                list_add_tail(&rxb->list, &priv->rxq.rx_used);
                 spin_unlock_irqrestore(&rxq->lock, flags);
+
                 i = (i + 1) & RX_QUEUE_MASK;
                 /* If there are a lot of unused frames,
                  * restock the Rx queue so ucode won't assert. */
                 if (fill_rx) {
                         count++;
                         if (count >= 8) {
-                                priv->rxq.read = i;
+                                rxq->read = i;
                                 iwl3945_rx_replenish_now(priv);
                                 count = 0;
                         }
@@ -1464,7 +1467,7 @@ static void iwl3945_rx_handle(struct iwl_priv *priv)
         }
 
         /* Backtrack one entry */
-        priv->rxq.read = i;
+        rxq->read = i;
         if (fill_rx)
                 iwl3945_rx_replenish_now(priv);
         else