From de0bd50845eb5935ce3d503c5d2f565d6cb9ece1 Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Fri, 11 Sep 2009 10:38:12 -0700 Subject: iwlwifi: fix potential rx buffer loss RX handling maintains a few lists that keep track of the RX buffers. Buffers move from one list to the other as they are used, replenished, and again made available for usage. In one such instance, when a buffer is used it enters the "rx_used" list. When buffers are replenished an skb is attached to the buffer and it is moved to the "rx_free" list. The problem here is that the buffer is first removed from the "rx_used" list _before_ the skb is allocated. Thus, if the skb allocation fails this buffer remains removed from the "rx_used" list and is thus lost for future usage. Fix this by first allocating the skb before trying to attach it to a list. We add an additional check to not do this unnecessarily. Reported-by: Rick Farrington Signed-off-by: Reinette Chatre Signed-off-by: John W. Linville --- drivers/net/wireless/iwlwifi/iwl-rx.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) (limited to 'drivers/net/wireless/iwlwifi/iwl-rx.c') diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c index 8150c5c3a16..b90adcb73b0 100644 --- a/drivers/net/wireless/iwlwifi/iwl-rx.c +++ b/drivers/net/wireless/iwlwifi/iwl-rx.c @@ -239,26 +239,22 @@ void iwl_rx_allocate(struct iwl_priv *priv, gfp_t priority) struct iwl_rx_queue *rxq = &priv->rxq; struct list_head *element; struct iwl_rx_mem_buffer *rxb; + struct sk_buff *skb; unsigned long flags; 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, + skb = alloc_skb(priv->hw_params.rx_buf_size + 256, priority); - if (!rxb->skb) { + if (!skb) { IWL_CRIT(priv, "Can not allocate SKB buffers\n"); /* We don't reschedule replenish work here -- we will * call the restock method and if it still needs @@ -266,6 +262,20 @@ void iwl_rx_allocate(struct iwl_priv *priv, gfp_t priority) break; } + spin_lock_irqsave(&rxq->lock, flags); + + if (list_empty(&rxq->rx_used)) { + spin_unlock_irqrestore(&rxq->lock, flags); + dev_kfree_skb_any(skb); + 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); + + rxb->skb = skb; /* Get physical address of RB/SKB */ rxb->real_dma_addr = pci_map_single( priv->pci_dev, -- cgit v1.2.3-70-g09d2 From f82a924cc88a5541df1d4b9d38a0968cd077a051 Mon Sep 17 00:00:00 2001 From: Reinette Chatre Date: Thu, 17 Sep 2009 10:43:56 -0700 Subject: iwlwifi: reduce noise when skb allocation fails Replenishment of receive buffers is done in the tasklet handling received frames as well as in a workqueue. When we are in the tasklet we cannot sleep and thus attempt atomic skb allocations. It is generally not a big problem if this fails since iwl_rx_allocate is always followed by a call to iwl_rx_queue_restock which will queue the work to replenish the buffers at a time when sleeping is allowed. We thus add the __GFP_NOWARN to the skb allocation in iwl_rx_allocate to reduce the noise if such an allocation fails while we still have enough buffers. We do maintain the warning and the error message when we are low on buffers to communicate to the user that there is a potential problem with memory availability on system This addresses issue reported upstream in thread "iwlagn: order 2 page allocation failures" in http://thread.gmane.org/gmane.linux.kernel.wireless.general/39187 Signed-off-by: Reinette Chatre Acked-by: Mel Gorman Signed-off-by: John W. Linville --- drivers/net/wireless/iwlwifi/iwl-rx.c | 10 +++++++++- drivers/net/wireless/iwlwifi/iwl3945-base.c | 9 ++++++++- 2 files changed, 17 insertions(+), 2 deletions(-) (limited to 'drivers/net/wireless/iwlwifi/iwl-rx.c') diff --git a/drivers/net/wireless/iwlwifi/iwl-rx.c b/drivers/net/wireless/iwlwifi/iwl-rx.c index b90adcb73b0..8e1bb53c0aa 100644 --- a/drivers/net/wireless/iwlwifi/iwl-rx.c +++ b/drivers/net/wireless/iwlwifi/iwl-rx.c @@ -250,12 +250,20 @@ void iwl_rx_allocate(struct iwl_priv *priv, gfp_t priority) } spin_unlock_irqrestore(&rxq->lock, flags); + if (rxq->free_count > RX_LOW_WATERMARK) + priority |= __GFP_NOWARN; /* Alloc a new receive buffer */ skb = alloc_skb(priv->hw_params.rx_buf_size + 256, priority); if (!skb) { - IWL_CRIT(priv, "Can not allocate SKB buffers\n"); + if (net_ratelimit()) + IWL_DEBUG_INFO(priv, "Failed to allocate SKB buffer.\n"); + if ((rxq->free_count <= RX_LOW_WATERMARK) && + net_ratelimit()) + IWL_CRIT(priv, "Failed to allocate SKB buffer with %s. Only %u free buffers remaining.\n", + priority == GFP_ATOMIC ? "GFP_ATOMIC" : "GFP_KERNEL", + rxq->free_count); /* We don't reschedule replenish work here -- we will * call the restock method and if it still needs * more buffers it will schedule replenish */ diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c index 090966837f3..4f2d4393728 100644 --- a/drivers/net/wireless/iwlwifi/iwl3945-base.c +++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c @@ -1146,11 +1146,18 @@ static void iwl3945_rx_allocate(struct iwl_priv *priv, gfp_t priority) } spin_unlock_irqrestore(&rxq->lock, flags); + if (rxq->free_count > RX_LOW_WATERMARK) + priority |= __GFP_NOWARN; /* Alloc a new receive buffer */ skb = alloc_skb(priv->hw_params.rx_buf_size, priority); if (!skb) { if (net_ratelimit()) - IWL_CRIT(priv, ": Can not allocate SKB buffers\n"); + IWL_DEBUG_INFO(priv, "Failed to allocate SKB buffer.\n"); + if ((rxq->free_count <= RX_LOW_WATERMARK) && + net_ratelimit()) + IWL_CRIT(priv, "Failed to allocate SKB buffer with %s. Only %u free buffers remaining.\n", + priority == GFP_ATOMIC ? "GFP_ATOMIC" : "GFP_KERNEL", + rxq->free_count); /* We don't reschedule replenish work here -- we will * call the restock method and if it still needs * more buffers it will schedule replenish */ -- cgit v1.2.3-70-g09d2