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From: Christoph Hellwig <hch@infradead.org>
To: Vivek Gautam <vivek.gautam@codeaurora.org>
Cc: airlied@linux.ie, robdclark@gmail.com, tfiga@chromium.org,
	linux-kernel@vger.kernel.org, freedreno@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
	Jordan Crouse <jcrouse@codeaurora.org>,
	Sean Paul <seanpaul@chromium.org>
Subject: Re: [PATCH v2 1/1] drm: msm: Replace dma_map_sg with dma_sync_sg*
Date: Tue, 27 Nov 2018 23:39:40 -0800	[thread overview]
Message-ID: <20181128073940.GA13072@infradead.org> (raw)
In-Reply-To: <20181126213710.3084-1-vivek.gautam@codeaurora.org>

> +		/*
> +		 * dma_sync_sg_*() flush the physical pages, so point
> +		 * sg->dma_address to the physical ones for the right behavior.
> +		 */
> +		for_each_sg(msm_obj->sgt->sgl, s, msm_obj->sgt->nents, i)
> +			sg_dma_address(s) = sg_phys(s);
> +

I'm sorry, but this is completely bogus and not acceptable.

The only place that is allowed to initialize sg_dma_address is
dma_map_sg.  If the default dma ops don't work for your setup we have
major a problem and need to fix the dma api / iommu integration instead
of hacking around it.

  parent reply	other threads:[~2018-11-28  7:39 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-26 21:37 [PATCH v2 1/1] drm: msm: Replace dma_map_sg with dma_sync_sg* Vivek Gautam
     [not found] ` <20181126213710.3084-1-vivek.gautam-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
2018-11-28  3:09   ` Tomasz Figa
2018-11-29  9:43     ` Vivek Gautam
2018-11-28  7:39 ` Christoph Hellwig [this message]
     [not found]   ` <20181128073940.GA13072-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
2018-11-28  9:02     ` Vivek Gautam
2018-11-28 12:38     ` Rob Clark
     [not found]       ` <CAF6AEGuM-R0=KRSmT+bt6SBaZg_ea3A_YFE+xfR_oCH9d9uORA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-11-29  9:44         ` Vivek Gautam
2018-11-28 14:19   ` Lukas Wunner

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