From: Vinod Koul <vkoul@kernel.org>
To: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Dan Williams <dan.j.williams@intel.com>,
Eugeniu Rosca <erosca@de.adit-jv.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
Wolfram Sang <wsa+renesas@sang-engineering.com>,
linux-serial@vger.kernel.org, linux-renesas-soc@vger.kernel.org,
dmaengine@vger.kernel.org
Subject: Re: [PATCH] dmaengine: rcar-dmac: Reject zero-length slave DMA requests
Date: Tue, 25 Jun 2019 10:10:13 +0530 [thread overview]
Message-ID: <20190625044013.GL2962@vkoul-mobl> (raw)
In-Reply-To: <20190624123818.20919-1-geert+renesas@glider.be>
On 24-06-19, 14:38, Geert Uytterhoeven wrote:
> While the .device_prep_slave_sg() callback rejects empty scatterlists,
> it still accepts single-entry scatterlists with a zero-length segment.
> These may happen if a driver calls dmaengine_prep_slave_single() with a
> zero len parameter. The corresponding DMA request will never complete,
> leading to messages like:
>
> rcar-dmac e7300000.dma-controller: Channel Address Error happen
>
> and DMA timeouts.
>
> Although requesting a zero-length DMA request is a driver bug, rejecting
> it early eases debugging. Note that the .device_prep_dma_memcpy()
> callback already rejects requests to copy zero bytes.
Applied, thanks
--
~Vinod
next prev parent reply other threads:[~2019-06-25 4:43 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 12:38 [PATCH] dmaengine: rcar-dmac: Reject zero-length slave DMA requests Geert Uytterhoeven
2019-06-24 12:49 ` Wolfram Sang
2019-06-25 4:38 ` Vinod Koul
2019-06-25 4:40 ` Vinod Koul [this message]
2019-06-26 18:14 ` Eugeniu Rosca
2019-06-28 12:10 ` Geert Uytterhoeven
2019-06-28 12:57 ` Wolfram Sang
2019-07-03 15:34 ` Eugeniu Rosca
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