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Date: Wed, 22 May 2024 14:33:00 +0300
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Neil Armstrong <neil.armstrong@linaro.org>
Cc: =?iso-8859-1?Q?N=EDcolas_F=2E_R=2E_A=2E?= Prado <nfraprado@collabora.com>,
	Mark Brown <broonie@kernel.org>, linux-spi@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-msm <linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH v1 1/1] spi: Remove unneded check for orig_nents
Message-ID: <Zk3X7Dgst5kVzJxy@smile.fi.intel.com>
References: <20240507201028.564630-1-andriy.shevchenko@linux.intel.com>
 <d8930bce-6db6-45f4-8f09-8a00fa48e607@notapiano>
 <8ae675b5-fcf9-4c9b-b06a-4462f70e1322@linaro.org>
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On Wed, May 22, 2024 at 12:03:33PM +0200, Neil Armstrong wrote:
> On 15/05/2024 23:09, N?colas F. R. A. Prado wrote:
> > On Tue, May 07, 2024 at 11:10:27PM +0300, Andy Shevchenko wrote:
> > > Both dma_unmap_sgtable() and sg_free_table() in spi_unmap_buf_attrs()
> > > have checks for orig_nents against 0. No need to duplicate this.
> > > All the same applies to other DMA mapping API calls.
> > > 
> > > Also note, there is no other user in the kernel that does this kind of
> > > checks.
> > > 
> > > Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > 
> > Hi,
> > 
> > this commit caused a regression which I reported here:
> > 
> > https://lore.kernel.org/all/d3679496-2e4e-4a7c-97ed-f193bd53af1d@notapiano
> > 
> > along with some thoughts on the cause and a possible solution, though I'm not
> > familiar with this code base at all and would really appreciate any feedback you
> > may have.
> 
> I also see the same regression on the SM8550 and SM8650 platforms,
> please CC linux-arm-msm@vger.kernel.org and me for a potential fix to test on those platforms.

There is still no answer from IOMMU patch author. Do you have the same trace
due to IOMMU calls? Anyway, I guess it would be nice to see it.

Meanwhile, I have three changes I posted in the replies to the initial report,
can you combine them all and test? This will be a plan B (? or A, depending on
the culprit).

-- 
With Best Regards,
Andy Shevchenko