From d8b48911fd249bc1a3431a9515619403c96d6af3 Mon Sep 17 00:00:00 2001 From: Sergei Shtylyov Date: Wed, 22 Jul 2015 01:31:59 +0300 Subject: [PATCH] ravb: fix ring memory allocation The driver is written as if it can adapt to a low memory situation allocating less RX skbs and TX aligned buffers than the respective RX/TX ring sizes. In reality though the driver would malfunction in this case. Stop being overly smart and just fail in such situation -- this is achieved by moving the memory allocation from ravb_ring_format() to ravb_ring_init(). We leave dma_map_single() calls in place but make their failure non-fatal by marking the corresponding RX descriptors with zero data size which should prevent DMA to an invalid addresses. Signed-off-by: Sergei Shtylyov Signed-off-by: David S. Miller --- drivers/net/ethernet/renesas/ravb_main.c | 59 ++++++++++++++---------- 1 file changed, 34 insertions(+), 25 deletions(-) diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index d08c250e843e..78849dd4ef8e 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -228,9 +228,7 @@ static void ravb_ring_format(struct net_device *ndev, int q) struct ravb_desc *desc = NULL; int rx_ring_size = sizeof(*rx_desc) * priv->num_rx_ring[q]; int tx_ring_size = sizeof(*tx_desc) * priv->num_tx_ring[q]; - struct sk_buff *skb; dma_addr_t dma_addr; - void *buffer; int i; priv->cur_rx[q] = 0; @@ -241,41 +239,28 @@ static void ravb_ring_format(struct net_device *ndev, int q) memset(priv->rx_ring[q], 0, rx_ring_size); /* Build RX ring buffer */ for (i = 0; i < priv->num_rx_ring[q]; i++) { - priv->rx_skb[q][i] = NULL; - skb = netdev_alloc_skb(ndev, PKT_BUF_SZ + RAVB_ALIGN - 1); - if (!skb) - break; - ravb_set_buffer_align(skb); /* RX descriptor */ rx_desc = &priv->rx_ring[q][i]; /* The size of the buffer should be on 16-byte boundary. */ rx_desc->ds_cc = cpu_to_le16(ALIGN(PKT_BUF_SZ, 16)); - dma_addr = dma_map_single(&ndev->dev, skb->data, + dma_addr = dma_map_single(&ndev->dev, priv->rx_skb[q][i]->data, ALIGN(PKT_BUF_SZ, 16), DMA_FROM_DEVICE); - if (dma_mapping_error(&ndev->dev, dma_addr)) { - dev_kfree_skb(skb); - break; - } - priv->rx_skb[q][i] = skb; + /* We just set the data size to 0 for a failed mapping which + * should prevent DMA from happening... + */ + if (dma_mapping_error(&ndev->dev, dma_addr)) + rx_desc->ds_cc = cpu_to_le16(0); rx_desc->dptr = cpu_to_le32(dma_addr); rx_desc->die_dt = DT_FEMPTY; } rx_desc = &priv->rx_ring[q][i]; rx_desc->dptr = cpu_to_le32((u32)priv->rx_desc_dma[q]); rx_desc->die_dt = DT_LINKFIX; /* type */ - priv->dirty_rx[q] = (u32)(i - priv->num_rx_ring[q]); memset(priv->tx_ring[q], 0, tx_ring_size); /* Build TX ring buffer */ for (i = 0; i < priv->num_tx_ring[q]; i++) { - priv->tx_skb[q][i] = NULL; - priv->tx_buffers[q][i] = NULL; - buffer = kmalloc(PKT_BUF_SZ + RAVB_ALIGN - 1, GFP_KERNEL); - if (!buffer) - break; - /* Aligned TX buffer */ - priv->tx_buffers[q][i] = buffer; tx_desc = &priv->tx_ring[q][i]; tx_desc->die_dt = DT_EEMPTY; } @@ -298,7 +283,10 @@ static void ravb_ring_format(struct net_device *ndev, int q) static int ravb_ring_init(struct net_device *ndev, int q) { struct ravb_private *priv = netdev_priv(ndev); + struct sk_buff *skb; int ring_size; + void *buffer; + int i; /* Allocate RX and TX skb rings */ priv->rx_skb[q] = kcalloc(priv->num_rx_ring[q], @@ -308,12 +296,28 @@ static int ravb_ring_init(struct net_device *ndev, int q) if (!priv->rx_skb[q] || !priv->tx_skb[q]) goto error; + for (i = 0; i < priv->num_rx_ring[q]; i++) { + skb = netdev_alloc_skb(ndev, PKT_BUF_SZ + RAVB_ALIGN - 1); + if (!skb) + goto error; + ravb_set_buffer_align(skb); + priv->rx_skb[q][i] = skb; + } + /* Allocate rings for the aligned buffers */ priv->tx_buffers[q] = kcalloc(priv->num_tx_ring[q], sizeof(*priv->tx_buffers[q]), GFP_KERNEL); if (!priv->tx_buffers[q]) goto error; + for (i = 0; i < priv->num_tx_ring[q]; i++) { + buffer = kmalloc(PKT_BUF_SZ + RAVB_ALIGN - 1, GFP_KERNEL); + if (!buffer) + goto error; + /* Aligned TX buffer */ + priv->tx_buffers[q][i] = buffer; + } + /* Allocate all RX descriptors. */ ring_size = sizeof(struct ravb_ex_rx_desc) * (priv->num_rx_ring[q] + 1); priv->rx_ring[q] = dma_alloc_coherent(NULL, ring_size, @@ -524,6 +528,10 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q) if (--boguscnt < 0) break; + /* We use 0-byte descriptors to mark the DMA mapping errors */ + if (!pkt_len) + continue; + if (desc_status & MSC_MC) stats->multicast++; @@ -587,10 +595,11 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q) le16_to_cpu(desc->ds_cc), DMA_FROM_DEVICE); skb_checksum_none_assert(skb); - if (dma_mapping_error(&ndev->dev, dma_addr)) { - dev_kfree_skb_any(skb); - break; - } + /* We just set the data size to 0 for a failed mapping + * which should prevent DMA from happening... + */ + if (dma_mapping_error(&ndev->dev, dma_addr)) + desc->ds_cc = cpu_to_le16(0); desc->dptr = cpu_to_le32(dma_addr); priv->rx_skb[q][entry] = skb; } -- 2.20.1