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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>
This commit is contained in:
Zhu Yi 2008-12-17 16:52:33 +08:00 committed by John W. Linville
parent 4087f6f68c
commit f1bc4ac61f
2 changed files with 20 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
drivers/net/wireless/iwlwifi/iwl-agn.c
View File

@ -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;
}
}

29
drivers/net/wireless/iwlwifi/iwl-rx.c
View File

@ -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)
{