From d842a31f121eccaba639ff26a1757649abd7d58e Mon Sep 17 00:00:00 2001 From: Duan Fugang-B38611 Date: Thu, 14 Nov 2013 09:57:10 +0800 Subject: [PATCH] net:fec: fix WARNING caused by lack of calls to dma_mapping_error() The driver fails to check the results of DMA mapping and results in the following warning: (with kernel config "CONFIG_DMA_API_DEBUG" enable) ------------[ cut here ]------------ WARNING: at lib/dma-debug.c:937 check_unmap+0x43c/0x7d8() fec 2188000.ethernet: DMA-API: device driver failed to check map error[device address=0x00000000383a8040] [size=2048 bytes] [mapped as single] Modules linked in: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.10.17-16827-g9cdb0ba-dirty #188 [<80013c4c>] (unwind_backtrace+0x0/0xf8) from [<80011704>] (show_stack+0x10/0x14) [<80011704>] (show_stack+0x10/0x14) from [<80025614>] (warn_slowpath_common+0x4c/0x6c) [<80025614>] (warn_slowpath_common+0x4c/0x6c) from [<800256c8>] (warn_slowpath_fmt+0x30/0x40) [<800256c8>] (warn_slowpath_fmt+0x30/0x40) from [<8026bfdc>] (check_unmap+0x43c/0x7d8) [<8026bfdc>] (check_unmap+0x43c/0x7d8) from [<8026c584>] (debug_dma_unmap_page+0x6c/0x78) [<8026c584>] (debug_dma_unmap_page+0x6c/0x78) from [<8038049c>] (fec_enet_rx_napi+0x254/0x8a8) [<8038049c>] (fec_enet_rx_napi+0x254/0x8a8) from [<804dc8c0>] (net_rx_action+0x94/0x160) [<804dc8c0>] (net_rx_action+0x94/0x160) from [<8002c758>] (__do_softirq+0xe8/0x1d0) [<8002c758>] (__do_softirq+0xe8/0x1d0) from [<8002c8e8>] (do_softirq+0x4c/0x58) [<8002c8e8>] (do_softirq+0x4c/0x58) from [<8002cb50>] (irq_exit+0x90/0xc8) [<8002cb50>] (irq_exit+0x90/0xc8) from [<8000ea88>] (handle_IRQ+0x3c/0x94) [<8000ea88>] (handle_IRQ+0x3c/0x94) from [<8000855c>] (gic_handle_irq+0x28/0x5c) [<8000855c>] (gic_handle_irq+0x28/0x5c) from [<8000de00>] (__irq_svc+0x40/0x50) Exception stack(0x815a5f38 to 0x815a5f80) 5f20: 815a5f80 3b9aca00 5f40: 0fe52383 00000002 0dd8950e 00000002 81e7b080 00000000 00000000 815ac4d8 5f60: 806032ec 00000000 00000017 815a5f80 80059028 8041fc4c 60000013 ffffffff [<8000de00>] (__irq_svc+0x40/0x50) from [<8041fc4c>] (cpuidle_enter_state+0x50/0xf0) [<8041fc4c>] (cpuidle_enter_state+0x50/0xf0) from [<8041fd94>] (cpuidle_idle_call+0xa8/0x14c) [<8041fd94>] (cpuidle_idle_call+0xa8/0x14c) from [<8000edac>] (arch_cpu_idle+0x10/0x4c) [<8000edac>] (arch_cpu_idle+0x10/0x4c) from [<800582f8>] (cpu_startup_entry+0x60/0x130) [<800582f8>] (cpu_startup_entry+0x60/0x130) from [<80bc7a48>] (start_kernel+0x2d0/0x328) [<80bc7a48>] (start_kernel+0x2d0/0x328) from [<10008074>] (0x10008074) ---[ end trace c6edec32436e0042 ]--- Because dma-debug add new interfaces to debug dma mapping errors, pls refer to: http://lwn.net/Articles/516640/ After dma mapping, it must call dma_mapping_error() to check mapping error, otherwise the map_err_type alway is MAP_ERR_NOT_CHECKED, check_unmap() define the mapping is not checked and dump the error msg. So,add dma_mapping_error() checking to fix the WARNING And RX DMA buffers are used repeatedly and the driver copies it into an skb, fec_enet_rx() should not map or unmap, use dma_sync_single_for_cpu()/dma_sync_single_for_device() instead of dma_map_single()/dma_unmap_single(). There have another potential issue: fec_enet_rx() passes the DMA address to __va(). Physical and DMA addresses are *not* the same thing. They may differ if the device is behind an IOMMU or bounce buffering was required, or just because there is a fixed offset between the device and host physical addresses. Also fix it in this patch. ============================================= V2: add net_ratelimit() to limit map err message. use dma_sync_single_for_cpu() instead of dma_map_single(). fix the issue that pass DMA addresses to __va() to get virture address. V1: initial send ============================================= Signed-off-by: Fugang Duan Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/fec_main.c | 31 ++++++++++++++++++----- 1 file changed, 25 insertions(+), 6 deletions(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index b2793b91cc55..4cbebf3d80eb 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -386,7 +386,14 @@ fec_enet_start_xmit(struct sk_buff *skb, struct net_device *ndev) */ bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, bufaddr, FEC_ENET_TX_FRSIZE, DMA_TO_DEVICE); - + if (dma_mapping_error(&fep->pdev->dev, bdp->cbd_bufaddr)) { + bdp->cbd_bufaddr = 0; + fep->tx_skbuff[index] = NULL; + dev_kfree_skb_any(skb); + if (net_ratelimit()) + netdev_err(ndev, "Tx DMA memory map failed\n"); + return NETDEV_TX_OK; + } /* Send it on its way. Tell FEC it's ready, interrupt when done, * it's the last BD of the frame, and to put the CRC on the end. */ @@ -861,6 +868,7 @@ fec_enet_rx(struct net_device *ndev, int budget) struct bufdesc_ex *ebdp = NULL; bool vlan_packet_rcvd = false; u16 vlan_tag; + int index = 0; #ifdef CONFIG_M532x flush_cache_all(); @@ -916,10 +924,15 @@ fec_enet_rx(struct net_device *ndev, int budget) ndev->stats.rx_packets++; pkt_len = bdp->cbd_datlen; ndev->stats.rx_bytes += pkt_len; - data = (__u8*)__va(bdp->cbd_bufaddr); - dma_unmap_single(&fep->pdev->dev, bdp->cbd_bufaddr, - FEC_ENET_TX_FRSIZE, DMA_FROM_DEVICE); + if (fep->bufdesc_ex) + index = (struct bufdesc_ex *)bdp - + (struct bufdesc_ex *)fep->rx_bd_base; + else + index = bdp - fep->rx_bd_base; + data = fep->rx_skbuff[index]->data; + dma_sync_single_for_cpu(&fep->pdev->dev, bdp->cbd_bufaddr, + FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE); if (id_entry->driver_data & FEC_QUIRK_SWAP_FRAME) swap_buffer(data, pkt_len); @@ -999,8 +1012,8 @@ fec_enet_rx(struct net_device *ndev, int budget) napi_gro_receive(&fep->napi, skb); } - bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, data, - FEC_ENET_TX_FRSIZE, DMA_FROM_DEVICE); + dma_sync_single_for_device(&fep->pdev->dev, bdp->cbd_bufaddr, + FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE); rx_processing_done: /* Clear the status flags for this buffer */ status &= ~BD_ENET_RX_STATS; @@ -1719,6 +1732,12 @@ static int fec_enet_alloc_buffers(struct net_device *ndev) bdp->cbd_bufaddr = dma_map_single(&fep->pdev->dev, skb->data, FEC_ENET_RX_FRSIZE, DMA_FROM_DEVICE); + if (dma_mapping_error(&fep->pdev->dev, bdp->cbd_bufaddr)) { + fec_enet_free_buffers(ndev); + if (net_ratelimit()) + netdev_err(ndev, "Rx DMA memory map failed\n"); + return -ENOMEM; + } bdp->cbd_sc = BD_ENET_RX_EMPTY; if (fep->bufdesc_ex) {