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>