From: "Shimoda, Yoshihiro" <yoshihiro.shimoda.uh@renesas.com>
To: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: linux-kernel@vger.kernel.org, linux-sh@vger.kernel.org,
Vinod Koul <vinod.koul@intel.com>,
Magnus Damm <magnus.damm@gmail.com>,
linux-mmc@vger.kernel.org, alsa-devel@alsa-project.org,
linux-serial@vger.kernel.org, Paul Mundt <lethal@linux-sh.org>,
linux-usb@vger.kernel.org
Subject: Re: [PATCH/RFC] usb: fix renesas_usbhs to not schedule in atomic context
Date: Mon, 06 Feb 2012 17:52:33 +0900 [thread overview]
Message-ID: <4F2F94D1.1080308@renesas.com> (raw)
In-Reply-To: <Pine.LNX.4.64.1202031623000.6211@axis700.grange>
Hi Guennadi-san,
2012/02/04 0:43, Guennadi Liakhovetski wrote:
> The current renesas_usbhs driver triggers
>
> BUG: scheduling while atomic: ksoftirqd/0/3/0x00000102
>
> with enabled CONFIG_DEBUG_ATOMIC_SLEEP, by submitting DMA transfers from
> an atomic (tasklet) context, which is not supported by the shdma dmaengine
> driver. Fix it by switching to a work. Also simplify some list
> manipulations.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> ---
>
> Shimoda-san, this is the problem, that you were observing. However, it
> exists with the present version of shdma just as well as with the new one
> - on top of the simple DMA library. I marked it an RFC because (1) I only
> lightly tested it with the gadget device on mackerel with the mass storage
> gadget, and (2) I am somewhat concerned about races. Currently the work
> function runs with no locking and there are no usual cancel_work_sync()
> points in the patch. However, it has also been like this before with the
> tasklet implementation, which is not much better, and it looks like there
> are no asynchronous operations on the same packets like timeouts. Only
> asynchronous events, that I can think about are things like unloading the
> driver or unplugging the cable, but these have been there before too. It
> would become worse on SMP, I think. Comments welcome.
Thank you for the patch and comments.
I also tested this patch using the g_mass_storage and g_ether.
About your points, I think so, too.
So, I will write such a code.
Best regards,
Yoshihiro Shimoda
next prev parent reply other threads:[~2012-02-06 8:53 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-26 14:56 [PATCH 0/7 v2] extract a simple dmaengine library from shdma.c Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 1/7 v2] dmaengine: add a simple dma library Guennadi Liakhovetski
2012-01-26 17:34 ` [alsa-devel] " Sascha Hauer
2012-01-26 21:07 ` Guennadi Liakhovetski
2012-01-27 8:37 ` Shimoda, Yoshihiro
2012-01-27 8:48 ` Guennadi Liakhovetski
2012-01-31 11:03 ` Shimoda, Yoshihiro
2012-02-01 0:52 ` Guennadi Liakhovetski
2012-02-01 2:47 ` Shimoda, Yoshihiro
2012-02-02 22:19 ` Guennadi Liakhovetski
2012-02-03 8:47 ` Shimoda, Yoshihiro
2012-02-03 10:21 ` Guennadi Liakhovetski
2012-02-03 15:43 ` [PATCH/RFC] usb: fix renesas_usbhs to not schedule in atomic context Guennadi Liakhovetski
2012-02-05 14:54 ` Felipe Balbi
2012-02-06 10:11 ` Guennadi Liakhovetski
2012-02-06 10:31 ` Felipe Balbi
2012-02-06 8:52 ` Shimoda, Yoshihiro [this message]
2012-01-30 8:32 ` [PATCH 1/7 v2] dmaengine: add a simple dma library Vinod Koul
2012-01-30 9:34 ` Guennadi Liakhovetski
2012-01-31 6:41 ` Vinod Koul
2012-01-31 8:59 ` Guennadi Liakhovetski
2012-02-01 5:38 ` Vinod Koul
2012-02-03 16:38 ` Guennadi Liakhovetski
2012-02-06 2:54 ` Vinod Koul
2012-02-06 9:53 ` Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 2/7 v2] dma: shdma: prepare for simple DMA conversion Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 3/7 v2] mmc: sh_mmcif: remove unneeded struct sh_mmcif_dma, prepare for simple DMA Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 4/7 v2] mmc: sh_mobile_sdhi: prepare for conversion to " Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 5/7 v2] serial: sh-sci: " Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 6/7 v2] ASoC: SIU: " Guennadi Liakhovetski
2012-02-06 2:33 ` Vinod Koul
2012-02-06 9:11 ` Guennadi Liakhovetski
2012-01-26 14:56 ` [PATCH 7/7 v2] dma: shdma: convert to the simple DMA library Guennadi Liakhovetski
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