Re: [PATCH] gpio: pca953x: Fix pca953x_gpio_set_multiple() on 64-bit
From: Phil Reid
Date: Sat Mar 12 2016 - 10:27:31 EST
On 12/03/2016 12:31 AM, Geert Uytterhoeven wrote:
pca953x_gpio_set_multiple() divides by 4 to convert from longs to bytes,
which assumes a 32-bit platform, and is not correct on 64-bit platforms.
Use "sizeof(...)" instead to fix this.
Fixes: b4818afeacbd8182 ("gpio: pca953x: Add set_multiple to allow multiple bits to be set in one write.")
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Acked-by: Phil Reid <preid@xxxxxxxxxxxxxxxxx>
---
Untested, found by code inspection.
This bug was introduced in v4.5-rc1, but unless Linus (the other one ;-)
will make a v4.5-rc8, it's probably too late to get this fixed in v4.5.
---
drivers/gpio/gpio-pca953x.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
index 23196c5fc17ceb6b..99b375c959987fe9 100644
--- a/drivers/gpio/gpio-pca953x.c
+++ b/drivers/gpio/gpio-pca953x.c
@@ -367,9 +367,11 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
memcpy(reg_val, chip->reg_output, NBANK(chip));
mutex_lock(&chip->i2c_lock);
for(bank=0; bank<NBANK(chip); bank++) {
- unsigned bankmask = mask[bank/4] >> ((bank % 4) * 8);
+ unsigned bankmask = mask[bank / sizeof(*mask)] >>
+ ((bank % sizeof(*mask)) * 8);
if(bankmask) {
- unsigned bankval = bits[bank/4] >> ((bank % 4) * 8);
+ unsigned bankval = bits[bank / sizeof(*bits)] >>
+ ((bank % sizeof(*bits)) * 8);
reg_val[bank] = (reg_val[bank] & ~bankmask) | bankval;
}
}
--
Regards
Phil Reid
ElectroMagnetic Imaging Technology Pty Ltd
Development of Geophysical Instrumentation & Software
www.electromag.com.au
3 The Avenue, Midland WA 6056, AUSTRALIA
Ph: +61 8 9250 8100
Fax: +61 8 9250 7100
Email: preid@xxxxxxxxxxxxxxxxx