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Date:   Mon, 31 Jan 2022 13:55:00 +0000
From:   Mark Brown <broonie@kernel.org>
To:     Pratyush Yadav <p.yadav@ti.com>
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] spi: spi-mem: check if data buffers are on stack
Message-ID: <YffqNEzjIkApR1HS@sirena.org.uk>
References: <20220131114508.1028306-1-p.yadav@ti.com>
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On Mon, Jan 31, 2022 at 05:15:08PM +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.

Acked-by: Mark Brown <broonie@kernel.org>

> +	/* Buffers must be DMA-able. */
> +	if (op->data.dir == SPI_MEM_DATA_IN &&
> +	    object_is_on_stack(op->data.buf.in))

Might be worth a WARN_ON_ONCE() for debuggability?

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