e100: Add dma mapping error check

e100 uses pci_map_single, but fails to check for a dma mapping error after its
use, resulting in a stack trace:

[   46.656594] ------------[ cut here ]------------
[   46.657004] WARNING: at lib/dma-debug.c:933 check_unmap+0x47b/0x950()
[   46.657004] Hardware name: To Be Filled By O.E.M.
[   46.657004] e100 0000:00:0e.0: DMA-API: device driver failed to check map
error[device address=0x000000007a4540fa] [size=90 bytes] [mapped as single]
[   46.657004] Modules linked in:
[   46.657004]  w83627hf hwmon_vid snd_via82xx ppdev snd_ac97_codec ac97_bus
snd_seq snd_pcm snd_mpu401 snd_mpu401_uart ns558 snd_rawmidi gameport parport_pc
e100 snd_seq_device parport snd_page_alloc snd_timer snd soundcore skge shpchp
k8temp mii edac_core i2c_viapro edac_mce_amd nfsd auth_rpcgss nfs_acl lockd
sunrpc binfmt_misc uinput ata_generic pata_acpi radeon i2c_algo_bit
drm_kms_helper ttm firewire_ohci drm firewire_core pata_via sata_via i2c_core
sata_promise crc_itu_t
[   46.657004] Pid: 792, comm: ip Not tainted 3.8.0-0.rc6.git0.1.fc19.x86_64 #1
[   46.657004] Call Trace:
[   46.657004]  <IRQ>  [<ffffffff81065ed0>] warn_slowpath_common+0x70/0xa0
[   46.657004]  [<ffffffff81065f4c>] warn_slowpath_fmt+0x4c/0x50
[   46.657004]  [<ffffffff81364cfb>] check_unmap+0x47b/0x950
[   46.657004]  [<ffffffff8136522f>] debug_dma_unmap_page+0x5f/0x70
[   46.657004]  [<ffffffffa030f0f0>] ? e100_tx_clean+0x30/0x210 [e100]
[   46.657004]  [<ffffffffa030f1a8>] e100_tx_clean+0xe8/0x210 [e100]
[   46.657004]  [<ffffffffa030fc6f>] e100_poll+0x56f/0x6c0 [e100]
[   46.657004]  [<ffffffff8159dce1>] ? net_rx_action+0xa1/0x370
[   46.657004]  [<ffffffff8159ddb2>] net_rx_action+0x172/0x370
[   46.657004]  [<ffffffff810703bf>] __do_softirq+0xef/0x3d0
[   46.657004]  [<ffffffff816e4ebc>] call_softirq+0x1c/0x30
[   46.657004]  [<ffffffff8101c485>] do_softirq+0x85/0xc0
[   46.657004]  [<ffffffff81070885>] irq_exit+0xd5/0xe0
[   46.657004]  [<ffffffff816e5756>] do_IRQ+0x56/0xc0
[   46.657004]  [<ffffffff816dacb2>] common_interrupt+0x72/0x72
[   46.657004]  <EOI>  [<ffffffff816da1eb>] ?
_raw_spin_unlock_irqrestore+0x3b/0x70
[   46.657004]  [<ffffffff816d124d>] __slab_free+0x58/0x38b
[   46.657004]  [<ffffffff81214424>] ? fsnotify_clear_marks_by_inode+0x34/0x120
[   46.657004]  [<ffffffff811b0417>] ? kmem_cache_free+0x97/0x320
[   46.657004]  [<ffffffff8157fc14>] ? sock_destroy_inode+0x34/0x40
[   46.657004]  [<ffffffff8157fc14>] ? sock_destroy_inode+0x34/0x40
[   46.657004]  [<ffffffff811b0692>] kmem_cache_free+0x312/0x320
[   46.657004]  [<ffffffff8157fc14>] sock_destroy_inode+0x34/0x40
[   46.657004]  [<ffffffff811e8c28>] destroy_inode+0x38/0x60
[   46.657004]  [<ffffffff811e8d5e>] evict+0x10e/0x1a0
[   46.657004]  [<ffffffff811e9605>] iput+0xf5/0x180
[   46.657004]  [<ffffffff811e4338>] dput+0x248/0x310
[   46.657004]  [<ffffffff811ce0e1>] __fput+0x171/0x240
[   46.657004]  [<ffffffff811ce26e>] ____fput+0xe/0x10
[   46.657004]  [<ffffffff8108d54c>] task_work_run+0xac/0xe0
[   46.657004]  [<ffffffff8106c6ed>] do_exit+0x26d/0xc30
[   46.657004]  [<ffffffff8109eccc>] ? finish_task_switch+0x7c/0x120
[   46.657004]  [<ffffffff816dad58>] ? retint_swapgs+0x13/0x1b
[   46.657004]  [<ffffffff8106d139>] do_group_exit+0x49/0xc0
[   46.657004]  [<ffffffff8106d1c4>] sys_exit_group+0x14/0x20
[   46.657004]  [<ffffffff816e3b19>] system_call_fastpath+0x16/0x1b
[   46.657004] ---[ end trace 4468c44e2156e7d1 ]---
[   46.657004] Mapped at:
[   46.657004]  [<ffffffff813663d1>] debug_dma_map_page+0x91/0x140
[   46.657004]  [<ffffffffa030e8eb>] e100_xmit_prepare+0x12b/0x1c0 [e100]
[   46.657004]  [<ffffffffa030c924>] e100_exec_cb+0x84/0x140 [e100]
[   46.657004]  [<ffffffffa030e56a>] e100_xmit_frame+0x3a/0x190 [e100]
[   46.657004]  [<ffffffff8159ee89>] dev_hard_start_xmit+0x259/0x6c0

Easy fix, modify the cb paramter to e100_exec_cb to return an error, and do the
dma_mapping_error check in the obvious place

This was reported previously here:
http://article.gmane.org/gmane.linux.network/257893

But nobody stepped up and fixed it.

CC: Josh Boyer <jwboyer@redhat.com>
CC: e1000-devel@lists.sourceforge.net
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: Michal Jaegermann <michal@harddata.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/intel/e100.c

@@ -870,7 +870,7 @@ static int e100_exec_cmd(struct nic *nic, u8 cmd, dma_addr_t dma_addr)
 }
 
 static int e100_exec_cb(struct nic *nic, struct sk_buff *skb,
-	void (*cb_prepare)(struct nic *, struct cb *, struct sk_buff *))
+	int (*cb_prepare)(struct nic *, struct cb *, struct sk_buff *))
 {
 	struct cb *cb;
 	unsigned long flags;
@@ -888,10 +888,13 @@ static int e100_exec_cb(struct nic *nic, struct sk_buff *skb,
 	nic->cbs_avail--;
 	cb->skb = skb;
 
+	err = cb_prepare(nic, cb, skb);
+	if (err)
+		goto err_unlock;
+
 	if (unlikely(!nic->cbs_avail))
 		err = -ENOSPC;
 
-	cb_prepare(nic, cb, skb);
 
 	/* Order is important otherwise we'll be in a race with h/w:
 	 * set S-bit in current first, then clear S-bit in previous. */
@@ -1091,7 +1094,7 @@ static void e100_get_defaults(struct nic *nic)
 	nic->mii.mdio_write = mdio_write;
 }
 
-static void e100_configure(struct nic *nic, struct cb *cb, struct sk_buff *skb)
+static int e100_configure(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 {
 	struct config *config = &cb->u.config;
 	u8 *c = (u8 *)config;
@@ -1181,6 +1184,7 @@ static void e100_configure(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 	netif_printk(nic, hw, KERN_DEBUG, nic->netdev,
 		     "[16-23]=%02X:%02X:%02X:%02X:%02X:%02X:%02X:%02X\n",
 		     c[16], c[17], c[18], c[19], c[20], c[21], c[22], c[23]);
+	return 0;
 }
 
 /*************************************************************************
@@ -1331,7 +1335,7 @@ static const struct firmware *e100_request_firmware(struct nic *nic)
 	return fw;
 }
 
-static void e100_setup_ucode(struct nic *nic, struct cb *cb,
+static int e100_setup_ucode(struct nic *nic, struct cb *cb,
 			     struct sk_buff *skb)
 {
 	const struct firmware *fw = (void *)skb;
@@ -1358,6 +1362,7 @@ static void e100_setup_ucode(struct nic *nic, struct cb *cb,
 	cb->u.ucode[min_size] |= cpu_to_le32((BUNDLESMALL) ? 0xFFFF : 0xFF80);
 
 	cb->command = cpu_to_le16(cb_ucode | cb_el);
+	return 0;
 }
 
 static inline int e100_load_ucode_wait(struct nic *nic)
@@ -1400,18 +1405,20 @@ static inline int e100_load_ucode_wait(struct nic *nic)
 	return err;
 }
 
-static void e100_setup_iaaddr(struct nic *nic, struct cb *cb,
+static int e100_setup_iaaddr(struct nic *nic, struct cb *cb,
 	struct sk_buff *skb)
 {
 	cb->command = cpu_to_le16(cb_iaaddr);
 	memcpy(cb->u.iaaddr, nic->netdev->dev_addr, ETH_ALEN);
+	return 0;
 }
 
-static void e100_dump(struct nic *nic, struct cb *cb, struct sk_buff *skb)
+static int e100_dump(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 {
 	cb->command = cpu_to_le16(cb_dump);
 	cb->u.dump_buffer_addr = cpu_to_le32(nic->dma_addr +
 		offsetof(struct mem, dump_buf));
+	return 0;
 }
 
 static int e100_phy_check_without_mii(struct nic *nic)
@@ -1581,7 +1588,7 @@ static int e100_hw_init(struct nic *nic)
 	return 0;
 }
 
-static void e100_multi(struct nic *nic, struct cb *cb, struct sk_buff *skb)
+static int e100_multi(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 {
 	struct net_device *netdev = nic->netdev;
 	struct netdev_hw_addr *ha;
@@ -1596,6 +1603,7 @@ static void e100_multi(struct nic *nic, struct cb *cb, struct sk_buff *skb)
 		memcpy(&cb->u.multi.addr[i++ * ETH_ALEN], &ha->addr,
 			ETH_ALEN);
 	}
+	return 0;
 }
 
 static void e100_set_multicast_list(struct net_device *netdev)
@@ -1756,11 +1764,18 @@ static void e100_watchdog(unsigned long data)
 		  round_jiffies(jiffies + E100_WATCHDOG_PERIOD));
 }
 
-static void e100_xmit_prepare(struct nic *nic, struct cb *cb,
+static int e100_xmit_prepare(struct nic *nic, struct cb *cb,
 	struct sk_buff *skb)
 {
+	dma_addr_t dma_addr;
 	cb->command = nic->tx_command;
 
+	dma_addr = pci_map_single(nic->pdev,
+				  skb->data, skb->len, PCI_DMA_TODEVICE);
+	/* If we can't map the skb, have the upper layer try later */
+	if (pci_dma_mapping_error(nic->pdev, dma_addr))
+		return -ENOMEM;
+
 	/*
 	 * Use the last 4 bytes of the SKB payload packet as the CRC, used for
 	 * testing, ie sending frames with bad CRC.
@@ -1777,11 +1792,10 @@ static void e100_xmit_prepare(struct nic *nic, struct cb *cb,
 	cb->u.tcb.tcb_byte_count = 0;
 	cb->u.tcb.threshold = nic->tx_threshold;
 	cb->u.tcb.tbd_count = 1;
-	cb->u.tcb.tbd.buf_addr = cpu_to_le32(pci_map_single(nic->pdev,
-		skb->data, skb->len, PCI_DMA_TODEVICE));
-	/* check for mapping failure? */
+	cb->u.tcb.tbd.buf_addr = cpu_to_le32(dma_addr);
 	cb->u.tcb.tbd.size = cpu_to_le16(skb->len);
 	skb_tx_timestamp(skb);
+	return 0;
 }
 
 static netdev_tx_t e100_xmit_frame(struct sk_buff *skb,