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Subject: Re: [PATCH RESEND] mtd: m25p80: consider max message size in
 m25p80_read
To: Cyrille Pitchen <cyrille.pitchen@atmel.com>
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Cc: MTD Maling List <linux-mtd@lists.infradead.org>,
 "linux-spi@vger.kernel.org" <linux-spi@vger.kernel.org>
From: Heiner Kallweit <hkallweit1@gmail.com>
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Date: Fri, 28 Oct 2016 07:48:29 +0200
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Am 27.10.2016 um 23:23 schrieb Heiner Kallweit:
> Consider a message size limit when calculating the maximum amount
> of data that can be read.
> 
> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> ---
> v2:
> - use the new function spi_max_message_size
> 
> This patch was part of a series and is needed to correctly support
> reads > 64k on fsl-espi (as first user of spi_max_message_size).
> See commit 02a595d5d6e4 ("spi: fsl-espi: eliminate spi nor flash
> read loop")
> ---
>  drivers/mtd/devices/m25p80.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 9cf7fcd..16a7df2 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -172,7 +172,8 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
>  
>  	t[1].rx_buf = buf;
>  	t[1].rx_nbits = m25p80_rx_nbits(nor);
> -	t[1].len = min(len, spi_max_transfer_size(spi));
> +	t[1].len = min3(len, spi_max_transfer_size(spi),
> +			spi_max_message_size(spi) - t[0].len);
>  	spi_message_add_tail(&t[1], &m);
>  
>  	ret = spi_sync(spi, &m);
> 
Sorry, forgot that this needs to go to stable as well. Will send a v2.