Re: [PATCH] wireless: iwlwifi - add dma_mapping_error() checks to avoid warnings

[Shuah Khan <shuah.khan@hp.com>]

On Sun, 2012-11-04 at 10:16 +0100, Johannes Berg wrote:
> On Sat, 2012-11-03 at 19:40 -0600, Shuah Khan wrote:
> > Add missing dma_mapping_error() checks to validate dma addresses returned by
> > dma_map_page() calls to avoid the following warning:
> > 
> > [   28.475686] WARNING: at lib/dma-debug.c:933 check_unmap+0x459/0x8a0()
> > [   28.475688] Hardware name: HP EliteBook 6930p
> > [   28.475690] iwlwifi 0000:03:00.0: DMA-API: device driver failed to check map error[device address=0x00000000ffffa000] [size=8192 bytes] [mapped as page]
> > [   28.475691] Modules linked in: arc4 bnep rfcomm iwldvm mac80211 snd_hda_codec_analog radeon snd_hda_intel snd_hda_codec coretemp kvm_intel snd_hwdep snd_pcm iwlwifi kvm btusb bluetooth snd_seq_midi snd_rawmidi ttm cfg80211 snd_seq_midi_event drm_kms_helper pata_pcmcia drm snd_seq binfmt_misc pcmcia snd_timer snd_seq_device tpm_infineon snd dm_multipath yenta_socket joydev pcmcia_rsrc pcmcia_core hp_wmi psmouse hp_accel microcode soundcore i2c_algo_bit sparse_keymap wmi ppdev lpc_ich lis3lv02d snd_page_alloc video tpm_tis serio_raw parport_pc input_polldev mac_hid lp parport firewire_ohci firewire_core crc_itu_t sdhci_pci sdhci e1000e
> 
> Thanks for the report. Since I think doing BUG_ON() in such a scenario
> is a really bad idea, I've applied a different patch with your
> Reported-by.

Yeah. I wasn't sure about BUS() either. Did you notice the other cases
of BUG_ON() in this path in iwl_rx_allocate()? I would think those need
fixing as well.

              rxb->page_dma =
                        dma_map_page(trans->dev, page, 0,
                                     PAGE_SIZE <<
trans_pcie->rx_page_order,
                                     DMA_FROM_DEVICE);
                /* dma address must be no more than 36 bits */
                BUG_ON(rxb->page_dma & ~DMA_BIT_MASK(36));
                /* and also 256 byte aligned! */
                BUG_ON(rxb->page_dma & DMA_BIT_MASK(8));

Could you please send me commitID for the patch you did. I am interested
in seeing the failure handling in your patch?

-- Shuah