Re: [PATCH v2] spi: spi-mem: check if data buffers are on stack

From: Pratyush Yadav <p.yadav@ti.com>
To: Mark Brown <broonie@kernel.org>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>,
	Michael Walle <michael@walle.cc>,
	Miquel Raynal <miquel.raynal@bootlin.com>,
	Takahiro Kuwano <tkuw584924@gmail.com>,
	<linux-spi@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] spi: spi-mem: check if data buffers are on stack
Date: Thu, 21 Apr 2022 12:40:56 +0530	[thread overview]
Message-ID: <20220421071056.4o33vlhoqarod3ow@ti.com> (raw)
In-Reply-To: <YmAE2IVRgPyWxmbn@sirena.org.uk>

On 20/04/22 02:04PM, Mark Brown wrote:
> On Wed, Apr 20, 2022 at 03:50:22PM +0530, Pratyush Yadav wrote:
> > The buffers passed in the data phase must be DMA-able. Programmers often
> > don't realise this requirement and pass in buffers that reside on the
> > stack. This can be hard to spot when reviewing code. Reject ops if their
> > data buffer is on the stack to avoid this.
> > 
> > Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
> > Acked-by: Mark Brown <broonie@kernel.org>
> > ---
> > 
> > Changes in v2:
> > - Include task_stack.h. It might not get included indirectly on some
> >   platforms and can cause build failures.
> > - Add a WARN_ON_ONCE() for debuggability.
> > - Add Mark's Ack.
> 
> Since this is now an isolated patch does that mean whatever meant that I
> acked rather than applying this patch has gone in and I can now apply it
> directly?

Yes, you should be able to apply it directly. Miquel's spi-mem-ecc 
branch is now in 5.18-rc1 and later. Though this patch never conflicted 
with that branch to begin with. The spi-mem-ecc branch does not touch 
spi_mem_check_op() as far as I can see.

-- 
Regards,
Pratyush Yadav
Texas Instruments Inc.