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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 <acourbot@nvidia.com>
Acked-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Frank Rowand <frank.rowand@sonymobile.com>
Cc: Tim Bird <tim.bird@sonymobile.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2013-08-30 09:41:45 +02:00
parent 6c17aa0138
commit be1a4b1308
1 changed files with 25 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/gpio/gpiolib.c
View File

@ -1398,7 +1398,7 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
int status = -EPROBE_DEFER; int status = -EPROBE_DEFER;
unsigned long flags; unsigned long flags;
if (!desc) { if (!desc || !desc->chip) {
pr_warn("%s: invalid GPIO\n", __func__); pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL; return -EINVAL;
} }
@ -1406,8 +1406,6 @@ static int gpiod_request(struct gpio_desc *desc, const char *label)
spin_lock_irqsave(&gpio_lock, flags); spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip; chip = desc->chip;
if (chip == NULL)
goto done;
if (!try_module_get(chip->owner)) if (!try_module_get(chip->owner))
goto done; goto done;
@ -1630,16 +1628,20 @@ static int gpiod_direction_input(struct gpio_desc *desc)
int status = -EINVAL; int status = -EINVAL;
int offset; int offset;
if (!desc) { if (!desc || !desc->chip) {
pr_warn("%s: invalid GPIO\n", __func__); pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL; 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); spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip;
if (!chip || !chip->get || !chip->direction_input)
goto fail;
status = gpio_ensure_requested(desc); status = gpio_ensure_requested(desc);
if (status < 0) if (status < 0)
goto fail; goto fail;
@ -1691,7 +1693,7 @@ static int gpiod_direction_output(struct gpio_desc *desc, int value)
int status = -EINVAL; int status = -EINVAL;
int offset; int offset;
if (!desc) { if (!desc || !desc->chip) {
pr_warn("%s: invalid GPIO\n", __func__); pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL; 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)) if (!value && test_bit(FLAG_OPEN_SOURCE, &desc->flags))
return gpiod_direction_input(desc); 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); spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip;
if (!chip || !chip->set || !chip->direction_output)
goto fail;
status = gpio_ensure_requested(desc); status = gpio_ensure_requested(desc);
if (status < 0) if (status < 0)
goto fail; goto fail;
@ -1765,16 +1771,19 @@ static int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
int status = -EINVAL; int status = -EINVAL;
int offset; int offset;
if (!desc) { if (!desc || !desc->chip) {
pr_warn("%s: invalid GPIO\n", __func__); pr_warn("%s: invalid GPIO\n", __func__);
return -EINVAL; return -EINVAL;
} }
spin_lock_irqsave(&gpio_lock, flags);
chip = desc->chip; chip = desc->chip;
if (!chip || !chip->set || !chip->set_debounce) if (!chip->set || !chip->set_debounce) {
goto fail; pr_warn("%s: missing set() or set_debounce() operations\n",
__func__);
return -EIO;
}
spin_lock_irqsave(&gpio_lock, flags);
status = gpio_ensure_requested(desc); status = gpio_ensure_requested(desc);
if (status < 0) if (status < 0)