Return-path: Received: from charlotte.tuxdriver.com ([70.61.120.58]:56274 "EHLO smtp.tuxdriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751503Ab3GBMhh (ORCPT ); Tue, 2 Jul 2013 08:37:37 -0400 Date: Tue, 2 Jul 2013 08:37:17 -0400 From: Neil Horman To: Arend van Spriel Cc: Larry Finger , linville@tuxdriver.com, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Stable , Brett Rudley , "Franky (Zhenhui) Lin" , Hante Meuleman , brcm80211-dev-list@broadcom.com Subject: Re: [PATCH] brcmsmac: Fix WARNING caused by lack of calls to dma_mapping_error() Message-ID: <20130702123717.GA324@hmsreliant.think-freely.org> (sfid-20130702_143746_028122_19C4BACC) References: <1372712883-4464-1-git-send-email-Larry.Finger@lwfinger.net> <51D29391.4080000@broadcom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <51D29391.4080000@broadcom.com> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Tue, Jul 02, 2013 at 10:47:13AM +0200, Arend van Spriel wrote: > On 07/01/2013 11:08 PM, Larry Finger wrote: > >The driver fails to check the results of DMA mapping in twp places, which results > >in the following warning: > > > >[ 28.078515] ------------[ cut here ]------------ > >[ 28.078529] WARNING: at lib/dma-debug.c:937 check_unmap+0x47e/0x930() > >[ 28.078533] bcma-pci-bridge 0000:0e:00.0: DMA-API: device driver failed to check map error[device address=0x00000000b5d60d6c] [size=1876 bytes] [mapped as > > single] > >[ 28.078536] Modules linked in: bnep bluetooth vboxpci(O) vboxnetadp(O) vboxnetflt(O) vboxdrv(O) ipv6 b43 brcmsmac rtl8192cu rtl8192c_common rtlwifi mac802 > >11 brcmutil cfg80211 snd_hda_codec_conexant rng_core snd_hda_intel kvm_amd snd_hda_codec ssb kvm mmc_core snd_pcm snd_seq snd_timer snd_seq_device snd k8temp > > cordic joydev serio_raw hwmon sr_mod sg pcmcia pcmcia_core soundcore cdrom i2c_nforce2 i2c_core forcedeth bcma snd_page_alloc autofs4 ext4 jbd2 mbcache crc1 > >6 scsi_dh_alua scsi_dh_hp_sw scsi_dh_rdac scsi_dh_emc scsi_dh ata_generic pata_amd > >[ 28.078602] CPU: 1 PID: 2570 Comm: NetworkManager Tainted: G O 3.10.0-rc7-wl+ #42 > >[ 28.078605] Hardware name: Hewlett-Packard HP Pavilion dv2700 Notebook PC/30D6, BIOS F.27 11/27/2008 > >[ 28.078607] 0000000000000009 ffff8800bbb03ad8 ffffffff8144f898 ffff8800bbb03b18 > >[ 28.078612] ffffffff8103e1eb 0000000000000002 ffff8800b719f480 ffff8800b7b9c010 > >[ 28.078617] ffffffff824204c0 ffffffff81754d57 0000000000000754 ffff8800bbb03b78 > >[ 28.078622] Call Trace: > >[ 28.078624] [] dump_stack+0x19/0x1b > >[ 28.078634] [] warn_slowpath_common+0x6b/0xa0 > >[ 28.078638] [] warn_slowpath_fmt+0x41/0x50 > >[ 28.078650] [] check_unmap+0x47e/0x930 > >[ 28.078655] [] debug_dma_unmap_page+0x5c/0x70 > >[ 28.078679] [] dma64_getnextrxp+0x10c/0x190 [brcmsmac] > >[ 28.078691] [] dma_rx+0x62/0x240 [brcmsmac] > >[ 28.078707] [] brcms_c_dpc+0x211/0x9d0 [brcmsmac] > >[ 28.078717] [] ? brcms_dpc+0x27/0xf0 [brcmsmac] > >[ 28.078731] [] brcms_dpc+0x47/0xf0 [brcmsmac] > >[ 28.078736] [] tasklet_action+0x6c/0xf0 > >--snip-- > >[ 28.078974] [] SyS_sendmsg+0xd/0x20 > >[ 28.078979] [] tracesys+0xdd/0xe2 > >[ 28.078982] ---[ end trace 6164d1a08148e9c8 ]--- > >[ 28.078984] Mapped at: > >[ 28.078985] [] debug_dma_map_page+0x9d/0x150 > >[ 28.078989] [] dma_rxfill+0x102/0x3d0 [brcmsmac] > >[ 28.079001] [] brcms_c_init+0x87d/0x1100 [brcmsmac] > >[ 28.079010] [] brcms_init+0x21/0x30 [brcmsmac] > >[ 28.079018] [] brcms_c_up+0x150/0x430 [brcmsmac] > > > >As the patch adds a new failure mechanism to dma_rxfill(). When I changed the > >comment at the start of the routine to add that information, I also polished > >the wording. > > Thanks, Larry > > I think there a bugzilla issue for this that you might want to reference: > > https://bugzilla.kernel.org/show_bug.cgi?id=60261 > Thanks Larry, you beat me too it, feel free to reassign the bz to yourself. :) > >Signed-off-by: Larry Finger > >Cc: Stable > >Cc: Brett Rudley > >Cc: Arend van Spriel > >Cc: Franky (Zhenhui) Lin > >Cc: Hante Meuleman > >Cc: brcm80211-dev-list@broadcom.com > >--- > > > > drivers/net/wireless/brcm80211/brcmsmac/dma.c | 12 ++++++++---- > > 1 file changed, 8 insertions(+), 4 deletions(-) > > > >diff --git a/drivers/net/wireless/brcm80211/brcmsmac/dma.c b/drivers/net/wireless/brcm80211/brcmsmac/dma.c > >index 1860c57..6260571 100644 > >--- a/drivers/net/wireless/brcm80211/brcmsmac/dma.c > >+++ b/drivers/net/wireless/brcm80211/brcmsmac/dma.c > >@@ -1015,9 +1015,10 @@ static bool dma64_txidle(struct dma_info *di) > > > > /* > > * post receive buffers > >- * return false is refill failed completely and ring is empty this will stall > >- * the rx dma and user might want to call rxfill again asap. This unlikely > >- * happens on memory-rich NIC, but often on memory-constrained dongle > >+ * return false is refill failed completely or dma mapping failed. The ring > > Missed some polishing opportunity: return false is refill... -> > return false if refill... > > >+ * is empty, which will stall the rx dma and user might want to call rxfill > >+ * again asap. This is unlikely to happen on a memory-rich NIC, but often on > >+ * memory-constrained dongle > > */ > > bool dma_rxfill(struct dma_pub *pub) > > { > >@@ -1078,6 +1079,8 @@ bool dma_rxfill(struct dma_pub *pub) > > > > pa = dma_map_single(di->dmadev, p->data, di->rxbufsize, > > DMA_FROM_DEVICE); > >+ if (dma_mapping_error(di->dmadev,pa)) > >+ return false; Hmm, wouldn't it be better to set ring_empty to false and break out of the for loop here, in the event that you partially refilled the ring? Otherwise, a single dma mapping failure would let some useable descriptors go unused. Neil