iwlwifi: use GFP_KERNEL to allocate Rx SKB memory

Previously we allocate Rx SKB with GFP_ATOMIC flag. This is because we need
to hold a spinlock to protect the two rx_used and rx_free lists operation
in the rxq.

	spin_lock();
	...
	element = rxq->rx_used.next;
	element->skb = alloc_skb(..., GFP_ATOMIC);
	list_del(element);
	list_add_tail(&element->list, &rxq->rx_free);
	...
	spin_unlock();

After spliting the rx_used delete and rx_free insert into two operations,
we don't require the skb allocation in an atomic context any more (the
function itself is scheduled in a workqueue).

	spin_lock();
	...
	element = rxq->rx_used.next;
	list_del(element);
	...
	spin_unlock();
	...
	element->skb = alloc_skb(..., GFP_KERNEL);
	...
	spin_lock()
	...
	list_add_tail(&element->list, &rxq->rx_free);
	...
	spin_unlock();

This patch should fix the "iwlagn: Can not allocate SKB buffers" warning
we see recently.

Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Acked-by: Tomas Winkler <tomas.winkler@intel.com>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c
index a0051928d29827ae481b41082e9592497a8fd7c5..ff8635f0ed458a3fee353be6da534f97a160b36c 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-agn.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn.c
@@ -1110,16 +1110,6 @@ static void iwl_setup_rx_handlers(struct iwl_priv *priv)
        priv->cfg->ops->lib->rx_handler_setup(priv);
 }
 
-/*
- * this should be called while priv->lock is locked
-*/
-static void __iwl_rx_replenish(struct iwl_priv *priv)
-{
-       iwl_rx_allocate(priv);
-       iwl_rx_queue_restock(priv);
-}
-
-
 /**
  * iwl_rx_handle - Main entry function for receiving responses from uCode
  *
@@ -1228,7 +1218,7 @@ void iwl_rx_handle(struct iwl_priv *priv)
                        count++;
                        if (count >= 8) {
                                priv->rxq.read = i;
-                               __iwl_rx_replenish(priv);
+                               iwl_rx_queue_restock(priv);
                                count = 0;
                        }
                }

diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c
index 919a775121e47fb5dffe5fbd5be085f2232cb115..c5f1aa0feac8c49ecb635e44b7b89e1c98681158 100644 (file)
--- a/drivers/net/wireless/iwlwifi/iwl-rx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-rx.c
@@ -244,25 +244,31 @@ void iwl_rx_allocate(struct iwl_priv *priv)
        struct list_head *element;
        struct iwl_rx_mem_buffer *rxb;
        unsigned long flags;
-       spin_lock_irqsave(&rxq->lock, flags);
-       while (!list_empty(&rxq->rx_used)) {
+
+       while (1) {
+               spin_lock_irqsave(&rxq->lock, flags);
+
+               if (list_empty(&rxq->rx_used)) {
+                       spin_unlock_irqrestore(&rxq->lock, flags);
+                       return;
+               }
                element = rxq->rx_used.next;
                rxb = list_entry(element, struct iwl_rx_mem_buffer, list);
+               list_del(element);
+
+               spin_unlock_irqrestore(&rxq->lock, flags);
 
                /* Alloc a new receive buffer */
                rxb->skb = alloc_skb(priv->hw_params.rx_buf_size + 256,
-                               __GFP_NOWARN | GFP_ATOMIC);
+                                    GFP_KERNEL);
                if (!rxb->skb) {
-                       if (net_ratelimit())
-                               printk(KERN_CRIT DRV_NAME
-                                      ": Can not allocate SKB buffers\n");
+                       printk(KERN_CRIT DRV_NAME
+                                  "Can not allocate SKB buffers\n");
                        /* We don't reschedule replenish work here -- we will
                         * call the restock method and if it still needs
                         * more buffers it will schedule replenish */
                        break;
                }
-               priv->alloc_rxb_skb++;
-               list_del(element);
 
                /* Get physical address of RB/SKB */
                rxb->real_dma_addr = pci_map_single(
@@ -276,12 +282,15 @@ void iwl_rx_allocate(struct iwl_priv *priv)
                rxb->aligned_dma_addr = ALIGN(rxb->real_dma_addr, 256);
                skb_reserve(rxb->skb, rxb->aligned_dma_addr - rxb->real_dma_addr);
 
+               spin_lock_irqsave(&rxq->lock, flags);
+
                list_add_tail(&rxb->list, &rxq->rx_free);
                rxq->free_count++;
+               priv->alloc_rxb_skb++;
+
+               spin_unlock_irqrestore(&rxq->lock, flags);
        }
-       spin_unlock_irqrestore(&rxq->lock, flags);
 }
-EXPORT_SYMBOL(iwl_rx_allocate);
 
 void iwl_rx_replenish(struct iwl_priv *priv)
 {