From: Eric Anholt <eric@anholt.net>
To: "Gustavo A. R. Silva" <gustavo@embeddedor.com>,
Mark Brown <broonie@kernel.org>,
Stefan Wahren <stefan.wahren@i2se.com>,
Florian Fainelli <f.fainelli@gmail.com>,
Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
bcm-kernel-feedback-list@broadcom.com
Cc: linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org,
"Gustavo A. R. Silva" <garsilva@embeddedor.com>
Subject: Re: [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit
Date: Thu, 08 Feb 2018 08:22:54 +0000 [thread overview]
Message-ID: <87inb7c2ld.fsf@anholt.net> (raw)
In-Reply-To: <20180207160002.GA9292@embeddedgus>
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"Gustavo A. R. Silva" <gustavo@embeddedor.com> writes:
> Add suffix ULL to constant 9 in order to give the compiler complete
> information about the proper arithmetic to use. Notice that this
> constant is used in a context that expects an expression of type
> unsigned long long (64 bits, unsigned).
>
> The expression tfr->len * 9 * 1000000 is currently being evaluated
> using 32-bit arithmetic.
>
> Addresses-Coverity-ID: 1339619
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
The effect looks like it would be that we would have chosen polling mode
instead of waiting for interrupts for some transfers >477 seconds.
Seems like a good fix for an unlikely bug.
Reviewed-by: Eric Anholt <eric@anholt.net>
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next prev parent reply other threads:[~2018-02-08 8:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-07 16:00 [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit Gustavo A. R. Silva
2018-02-08 8:22 ` Eric Anholt [this message]
2018-02-12 17:57 ` Gustavo A. R. Silva
2018-02-08 9:54 ` Ard Biesheuvel
2018-02-12 18:04 ` Gustavo A. R. Silva
2018-02-12 18:45 ` Ard Biesheuvel
2018-02-12 19:10 ` Florian Fainelli
2018-02-12 19:11 ` Ard Biesheuvel
2018-02-12 19:14 ` Florian Fainelli
2018-02-12 19:31 ` Trent Piepho
2018-02-12 19:38 ` [PATCH] spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc Trent Piepho
2018-02-14 16:04 ` Mark Brown
2018-02-14 16:28 ` Applied "spi: bcm2835aux: Avoid 64-bit arithmetic in xfer len calc" to the spi tree Mark Brown
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