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From: Christoph Hellwig <hch@lst.de>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Christoph Hellwig <hch@lst.de>,
	Nicolin Chen <nicoleotsuka@gmail.com>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	vdumpa@nvidia.com, Russell King <linux@armlinux.org.uk>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Chris Zankel <chris@zankel.net>,
	Max Filippov <jcmvbkbc@gmail.com>, Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	Tony Lindgren <tony@atomide.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Thierry Reding <treding@nvidia.com>,
	Kees Cook <keescook@chromium.org>,
	iamjoonsoo.kim@lge.com,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-xtensa@linux-xtensa.org, iommu@lists.linux-foundation.org
Subject: Re: [PATCH v2 2/2] dma-contiguous: Use fallback alloc_pages for single pages
Date: Tue, 27 Aug 2019 09:50:21 +0200	[thread overview]
Message-ID: <20190827075021.GA953@lst.de> (raw)
In-Reply-To: <CAK7LNATYOLEboUTO4qPx2z7cqwDrHBO1HFHG8VzZEJ15STv+nw@mail.gmail.com>

On Tue, Aug 27, 2019 at 04:45:20PM +0900, Masahiro Yamada wrote:
> On Mon, Aug 26, 2019 at 4:33 PM Christoph Hellwig <hch@lst.de> wrote:
> >
> > On Mon, Aug 26, 2019 at 11:05:00AM +0900, Masahiro Yamada wrote:
> > > This is included in v5.3-rc6
> > > so I tested it.
> >
> > So there is no allocation failure, but you get I/O errors later?
> 
> Right.
> 
> >
> > Does the device use a device-private CMA area?
> 
> Not sure.
> My driver is drivers/mmc/host/sdhci-cadence.c
> It reuses routines in drivers/mmc/host/sdhci.c
> 
> 
> 
> >  Does it work with Linux
> > 5.2 if CONFIG_DMA_CMA is disabled?
> 
> No.
> 5.2 + disable CONFIG_DMA_CMA
> failed in the same way.

So it seems like the device wants CMA memory.   I guess the patch
below will fix it, but that isn't the solution.  Can you try it
to confirm?  In the end it probably assumes a dma mask it doesn't
set that the CMA memory satisfies or something similar.

diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 69cfb4345388..bd2f24aa7f19 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -236,7 +236,7 @@ struct page *dma_alloc_contiguous(struct device *dev, size_t size, gfp_t gfp)
 
 	if (dev && dev->cma_area)
 		cma = dev->cma_area;
-	else if (count > 1)
+	else
 		cma = dma_contiguous_default_area;
 
 	/* CMA can be used only in the context which permits sleeping */

  reply	other threads:[~2019-08-27  7:50 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-06 22:33 [PATCH v2 0/2] Optimize dma_*_from_contiguous calls Nicolin Chen
2019-05-06 22:33 ` [PATCH v2 1/2] dma-contiguous: Abstract dma_{alloc,free}_contiguous() Nicolin Chen
2019-05-24  1:52   ` [PATCH v2 1/2] dma-contiguous: Abstract dma_{alloc, free}_contiguous() dann frazier
2019-05-24  2:59     ` dann frazier
2019-05-24  3:49       ` Nicolin Chen
2019-05-06 22:33 ` [PATCH v2 2/2] dma-contiguous: Use fallback alloc_pages for single pages Nicolin Chen
2019-08-23 12:49   ` Masahiro Yamada
2019-08-23 12:56     ` Masahiro Yamada
2019-08-25  1:10       ` Christoph Hellwig
2019-08-26  2:05         ` Masahiro Yamada
2019-08-26  7:33           ` Christoph Hellwig
2019-08-27  7:45             ` Masahiro Yamada
2019-08-27  7:50               ` Christoph Hellwig [this message]
2019-08-27  9:03                 ` Masahiro Yamada
2019-08-27 11:55                   ` Christoph Hellwig
2019-08-28 10:53                     ` Masahiro Yamada
2019-08-28 12:23                       ` Masahiro Yamada
2019-08-29 11:45                         ` Masahiro Yamada
2019-08-23 22:11     ` Nicolin Chen
2019-08-26  1:56       ` Masahiro Yamada
2019-05-08 12:52 ` [PATCH v2 0/2] Optimize dma_*_from_contiguous calls Christoph Hellwig
2019-05-08 18:08   ` Nicolin Chen

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