Return-path: Received: from xc.sipsolutions.net ([83.246.72.84]:46441 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751885AbYKRK4w (ORCPT ); Tue, 18 Nov 2008 05:56:52 -0500 Subject: Re: [PATCH/RFT] iwlagn: fix RX skb alignment From: Johannes Berg To: John Linville Cc: Tomas Winkler , reinette chatre , Marcel Holtmann , "Luis R. Rodriguez" , "Rafael J. Wysocki" , Matt Mackall , Christophe Dumez , Zhu Yi , Jan =?UTF-8?Q?V=C4=8Del=C3=A1k?= , Thomas Witt , linux-wireless , Andres Freund In-Reply-To: <1226969241.4014.24.camel@johannes.berg> (sfid-20081118_014839_339263_738F563C) References: <1226969241.4014.24.camel@johannes.berg> (sfid-20081118_014839_339263_738F563C) Content-Type: text/plain Date: Tue, 18 Nov 2008 11:56:09 +0100 Message-Id: <1227005769.4014.50.camel@johannes.berg> (sfid-20081118_115655_227526_17663E35) Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: > I'd like to ask anyone who is CC'ed (those are people I know ran into > the bug) to try this patch. And here's a version against v2.6.28-rc5 (build tested only) --- drivers/net/wireless/iwlwifi/iwl-agn.c | 6 +++--- drivers/net/wireless/iwlwifi/iwl-dev.h | 3 ++- drivers/net/wireless/iwlwifi/iwl-rx.c | 26 +++++++++++++++++--------- 3 files changed, 22 insertions(+), 13 deletions(-) --- test-tree.orig/drivers/net/wireless/iwlwifi/iwl-agn.c 2008-11-18 11:51:49.000000000 +0100 +++ test-tree/drivers/net/wireless/iwlwifi/iwl-agn.c 2008-11-18 11:52:54.000000000 +0100 @@ -1384,7 +1384,7 @@ void iwl_rx_handle(struct iwl_priv *priv rxq->queue[i] = NULL; - pci_dma_sync_single_for_cpu(priv->pci_dev, rxb->dma_addr, + pci_dma_sync_single_for_cpu(priv->pci_dev, rxb->aligned_dma_addr, priv->hw_params.rx_buf_size, PCI_DMA_FROMDEVICE); pkt = (struct iwl_rx_packet *)rxb->skb->data; @@ -1436,8 +1436,8 @@ void iwl_rx_handle(struct iwl_priv *priv rxb->skb = NULL; } - pci_unmap_single(priv->pci_dev, rxb->dma_addr, - priv->hw_params.rx_buf_size, + pci_unmap_single(priv->pci_dev, rxb->real_dma_addr, + priv->hw_params.rx_buf_size + 256, PCI_DMA_FROMDEVICE); spin_lock_irqsave(&rxq->lock, flags); list_add_tail(&rxb->list, &priv->rxq.rx_used); --- test-tree.orig/drivers/net/wireless/iwlwifi/iwl-dev.h 2008-10-23 23:10:47.000000000 +0200 +++ test-tree/drivers/net/wireless/iwlwifi/iwl-dev.h 2008-11-18 11:52:54.000000000 +0100 @@ -89,7 +89,8 @@ extern struct iwl_cfg iwl5100_abg_cfg; #define DEFAULT_LONG_RETRY_LIMIT 4U struct iwl_rx_mem_buffer { - dma_addr_t dma_addr; + dma_addr_t real_dma_addr; + dma_addr_t aligned_dma_addr; struct sk_buff *skb; struct list_head list; }; --- test-tree.orig/drivers/net/wireless/iwlwifi/iwl-rx.c 2008-10-23 23:10:47.000000000 +0200 +++ test-tree/drivers/net/wireless/iwlwifi/iwl-rx.c 2008-11-18 11:54:13.000000000 +0100 @@ -204,7 +204,7 @@ int iwl_rx_queue_restock(struct iwl_priv list_del(element); /* Point to Rx buffer via next RBD in circular buffer */ - rxq->bd[rxq->write] = iwl_dma_addr2rbd_ptr(priv, rxb->dma_addr); + rxq->bd[rxq->write] = iwl_dma_addr2rbd_ptr(priv, rxb->aligned_dma_addr); rxq->queue[rxq->write] = rxb; rxq->write = (rxq->write + 1) & RX_QUEUE_MASK; rxq->free_count--; @@ -251,7 +251,7 @@ void iwl_rx_allocate(struct iwl_priv *pr rxb = list_entry(element, struct iwl_rx_mem_buffer, list); /* Alloc a new receive buffer */ - rxb->skb = alloc_skb(priv->hw_params.rx_buf_size, + rxb->skb = alloc_skb(priv->hw_params.rx_buf_size + 256, __GFP_NOWARN | GFP_ATOMIC); if (!rxb->skb) { if (net_ratelimit()) @@ -266,9 +266,17 @@ void iwl_rx_allocate(struct iwl_priv *pr list_del(element); /* Get physical address of RB/SKB */ - rxb->dma_addr = - pci_map_single(priv->pci_dev, rxb->skb->data, - priv->hw_params.rx_buf_size, PCI_DMA_FROMDEVICE); + rxb->real_dma_addr = pci_map_single( + priv->pci_dev, + rxb->skb->data, + priv->hw_params.rx_buf_size + 256, + PCI_DMA_FROMDEVICE); + /* dma address must be no more than 36 bits */ + BUG_ON(rxb->real_dma_addr & ~DMA_BIT_MASK(36)); + /* and also 256 byte aligned! */ + rxb->aligned_dma_addr = ALIGN(rxb->real_dma_addr, 256); + skb_reserve(rxb->skb, rxb->aligned_dma_addr - rxb->real_dma_addr); + list_add_tail(&rxb->list, &rxq->rx_free); rxq->free_count++; } @@ -300,8 +308,8 @@ void iwl_rx_queue_free(struct iwl_priv * for (i = 0; i < RX_QUEUE_SIZE + RX_FREE_BUFFERS; i++) { if (rxq->pool[i].skb != NULL) { pci_unmap_single(priv->pci_dev, - rxq->pool[i].dma_addr, - priv->hw_params.rx_buf_size, + rxq->pool[i].real_dma_addr, + priv->hw_params.rx_buf_size + 256, PCI_DMA_FROMDEVICE); dev_kfree_skb(rxq->pool[i].skb); } @@ -354,8 +362,8 @@ void iwl_rx_queue_reset(struct iwl_priv * to an SKB, so we need to unmap and free potential storage */ if (rxq->pool[i].skb != NULL) { pci_unmap_single(priv->pci_dev, - rxq->pool[i].dma_addr, - priv->hw_params.rx_buf_size, + rxq->pool[i].real_dma_addr, + priv->hw_params.rx_buf_size + 256, PCI_DMA_FROMDEVICE); priv->alloc_rxb_skb--; dev_kfree_skb(rxq->pool[i].skb);