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From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Mark Brown <broonie@kernel.org>, Eric Anholt <eric@anholt.net>,
	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: [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit
Date: Wed, 7 Feb 2018 10:00:02 -0600	[thread overview]
Message-ID: <20180207160002.GA9292@embeddedgus> (raw)

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>
---
 drivers/spi/spi-bcm2835aux.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 7428091..a768c23 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -363,7 +363,7 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master,
 	 * chunk getting transferred - in our case the chunk size
 	 * is 3 bytes, so we approximate this by 9 bits/byte
 	 */
-	xfer_time_us = tfr->len * 9 * 1000000;
+	xfer_time_us = tfr->len * 9ULL * 1000000;
 	do_div(xfer_time_us, spi_used_hz);
 
 	/* run in polling mode for short transfers */
-- 
2.7.4

WARNING: multiple messages have this Message-ID (diff)
From: gustavo@embeddedor.com (Gustavo A. R. Silva)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] spi: bcm2835aux: use 64-bit arithmetic instead of 32-bit
Date: Wed, 7 Feb 2018 10:00:02 -0600	[thread overview]
Message-ID: <20180207160002.GA9292@embeddedgus> (raw)

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>
---
 drivers/spi/spi-bcm2835aux.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c
index 7428091..a768c23 100644
--- a/drivers/spi/spi-bcm2835aux.c
+++ b/drivers/spi/spi-bcm2835aux.c
@@ -363,7 +363,7 @@ static int bcm2835aux_spi_transfer_one(struct spi_master *master,
 	 * chunk getting transferred - in our case the chunk size
 	 * is 3 bytes, so we approximate this by 9 bits/byte
 	 */
-	xfer_time_us = tfr->len * 9 * 1000000;
+	xfer_time_us = tfr->len * 9ULL * 1000000;
 	do_div(xfer_time_us, spi_used_hz);
 
 	/* run in polling mode for short transfers */
-- 
2.7.4

             reply	other threads:[~2018-02-07 16:00 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-07 16:00 Gustavo A. R. Silva [this message]
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
2018-02-08  8:22   ` Eric Anholt
2018-02-12 17:57   ` Gustavo A. R. Silva
2018-02-12 17:57     ` Gustavo A. R. Silva
2018-02-08  9:54 ` Ard Biesheuvel
2018-02-08  9:54   ` Ard Biesheuvel
2018-02-08  9:54   ` Ard Biesheuvel
2018-02-12 18:04   ` Gustavo A. R. Silva
2018-02-12 18:04     ` Gustavo A. R. Silva
2018-02-12 18:45     ` Ard Biesheuvel
2018-02-12 18:45       ` Ard Biesheuvel
2018-02-12 19:10       ` Florian Fainelli
2018-02-12 19:10         ` Florian Fainelli
2018-02-12 19:10         ` Florian Fainelli
2018-02-12 19:11         ` Ard Biesheuvel
2018-02-12 19:11           ` Ard Biesheuvel
2018-02-12 19:11           ` Ard Biesheuvel
2018-02-12 19:14           ` Florian Fainelli
2018-02-12 19:14             ` Florian Fainelli
2018-02-12 19:14             ` Florian Fainelli
2018-02-12 19:31 ` Trent Piepho
2018-02-12 19:31   ` Trent Piepho
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
2018-02-12 19:38     ` Trent Piepho
2018-02-14 16:04     ` Mark Brown
2018-02-14 16:04       ` Mark Brown
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
2018-02-14 16:28       ` Mark Brown

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