From be1a4b13089b1e18da83a549d49163ccad3c19ba Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Fri, 30 Aug 2013 09:41:45 +0200 Subject: gpio: improve error path in gpiolib At several places the gpiolib will proceed to handle a GPIO descriptor even if it's ->chip member is NULL and no gpiochip is associated. Fix this by checking that both the descriptor cookie *and* the chip pointer are valid. Also bail out earlier with more specific diagnostic messages on missing operations for setting as input/output or debounce. ChangeLog v1->v2: - Also return -EIO on gpiod_set_debounce() with missing operations in the vtable - Fix indentations. Suggested-by: Alexandre Courbot Acked-by: Alexandre Courbot Reviewed-by: Frank Rowand Cc: Tim Bird Signed-off-by: Linus Walleij --- drivers/gpio/gpiolib.c | 41 +++++++++++++++++++++++++---------------- 1 file changed, 25 insertions(+), 16 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index d6413b2e0844..0cbdddab4ff2 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1398,7 +1398,7 @@ static int gpiod_request(struct gpio_desc *desc, const char *label) int status = -EPROBE_DEFER; unsigned long flags; - if (!desc) { + if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } @@ -1406,8 +1406,6 @@ static int gpiod_request(struct gpio_desc *desc, const char *label) spin_lock_irqsave(&gpio_lock, flags); chip = desc->chip; - if (chip == NULL) - goto done; if (!try_module_get(chip->owner)) goto done; @@ -1630,16 +1628,20 @@ static int gpiod_direction_input(struct gpio_desc *desc) int status = -EINVAL; int offset; - if (!desc) { + if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } + chip = desc->chip; + if (!chip->get || !chip->direction_input) { + pr_warn("%s: missing get() or direction_input() operations\n", + __func__); + return -EIO; + } + spin_lock_irqsave(&gpio_lock, flags); - chip = desc->chip; - if (!chip || !chip->get || !chip->direction_input) - goto fail; status = gpio_ensure_requested(desc); if (status < 0) goto fail; @@ -1691,7 +1693,7 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value) int status = -EINVAL; int offset; - if (!desc) { + if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } @@ -1704,11 +1706,15 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value) if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags)) return gpiod_direction_input(desc); + chip = desc->chip; + if (!chip->set || !chip->direction_output) { + pr_warn("%s: missing set() or direction_output() operations\n", + __func__); + return -EIO; + } + spin_lock_irqsave(&gpio_lock, flags); - chip = desc->chip; - if (!chip || !chip->set || !chip->direction_output) - goto fail; status = gpio_ensure_requested(desc); if (status < 0) goto fail; @@ -1765,16 +1771,19 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce) int status = -EINVAL; int offset; - if (!desc) { + if (!desc || !desc->chip) { pr_warn("%s: invalid GPIO\n", __func__); return -EINVAL; } - spin_lock_irqsave(&gpio_lock, flags); - chip = desc->chip; - if (!chip || !chip->set || !chip->set_debounce) - goto fail; + if (!chip->set || !chip->set_debounce) { + pr_warn("%s: missing set() or set_debounce() operations\n", + __func__); + return -EIO; + } + + spin_lock_irqsave(&gpio_lock, flags); status = gpio_ensure_requested(desc); if (status < 0) -- cgit v1.2.3