From b6ac1280b6969607c5a01e316cc4ab693490c333 Mon Sep 17 00:00:00 2001 From: Joshua Scott Date: Fri, 22 May 2015 12:35:12 +1200 Subject: gpio: Prevent an integer overflow in the pca953x driver Interrupts were missed if an 8-bit integer overflow occurred. This was observed when bank0,pin7 and bank1,pin7 changed simultaniously. As the 8-bit totals were only checked against zero, replace them with booleans. Name the booleans so that their purpose is clear. Signed-off-by: Joshua Scott Reviewed-by: Alexandre Courbot Signed-off-by: Linus Walleij --- drivers/gpio/gpio-pca953x.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) (limited to 'drivers/gpio/gpio-pca953x.c') diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c index eed42035207d..d233eb3b8132 100644 --- a/drivers/gpio/gpio-pca953x.c +++ b/drivers/gpio/gpio-pca953x.c @@ -443,12 +443,13 @@ static struct irq_chip pca953x_irq_chip = { .irq_set_type = pca953x_irq_set_type, }; -static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) +static bool pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) { u8 cur_stat[MAX_BANK]; u8 old_stat[MAX_BANK]; - u8 pendings = 0; - u8 trigger[MAX_BANK], triggers = 0; + bool pending_seen = false; + bool trigger_seen = false; + u8 trigger[MAX_BANK]; int ret, i, offset = 0; switch (chip->chip_type) { @@ -461,7 +462,7 @@ static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) } ret = pca953x_read_regs(chip, offset, cur_stat); if (ret) - return 0; + return false; /* Remove output pins from the equation */ for (i = 0; i < NBANK(chip); i++) @@ -471,11 +472,12 @@ static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) for (i = 0; i < NBANK(chip); i++) { trigger[i] = (cur_stat[i] ^ old_stat[i]) & chip->irq_mask[i]; - triggers += trigger[i]; + if (trigger[i]) + trigger_seen = true; } - if (!triggers) - return 0; + if (!trigger_seen) + return false; memcpy(chip->irq_stat, cur_stat, NBANK(chip)); @@ -483,10 +485,11 @@ static u8 pca953x_irq_pending(struct pca953x_chip *chip, u8 *pending) pending[i] = (old_stat[i] & chip->irq_trig_fall[i]) | (cur_stat[i] & chip->irq_trig_raise[i]); pending[i] &= trigger[i]; - pendings += pending[i]; + if (pending[i]) + pending_seen = true; } - return pendings; + return pending_seen; } static irqreturn_t pca953x_irq_handler(int irq, void *devid) -- cgit v1.2.3