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Subject[PATCH 1/4] gpio: Remove VLA from gpiolib
Date


The new challenge is to remove VLAs from the kernel
(see https://lkml.org/lkml/2018/3/7/621)

This patch replaces several VLAs with an appropriate call to
kmalloc_array.

Signed-off-by: Laura Abbott <labbott@redhat.com>
---
drivers/gpio/gpiolib.c | 55 +++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 48 insertions(+), 7 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index d66de67ef307..124727c74931 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2662,16 +2662,33 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,

while (i < array_size) {
struct gpio_chip *chip = desc_array[i]->gdev->chip;
- unsigned long mask[BITS_TO_LONGS(chip->ngpio)];
- unsigned long bits[BITS_TO_LONGS(chip->ngpio)];
+ unsigned long *mask;
+ unsigned long *bits;
int first, j, ret;

+ mask = kmalloc_array(BITS_TO_LONGS(chip->ngpio),
+ sizeof(*mask),
+ can_sleep ? GFP_KERNEL : GFP_ATOMIC);
+
+ if (!mask)
+ return -ENOMEM;
+
+ bits = kmalloc_array(BITS_TO_LONGS(chip->ngpio),
+ sizeof(*bits),
+ can_sleep ? GFP_KERNEL : GFP_ATOMIC);
+
+ if (!bits) {
+ kfree(mask);
+ return -ENOMEM;
+ }
+
+
if (!can_sleep)
WARN_ON(chip->can_sleep);

/* collect all inputs belonging to the same chip */
first = i;
- memset(mask, 0, sizeof(mask));
+ memset(mask, 0, sizeof(*mask));
do {
const struct gpio_desc *desc = desc_array[i];
int hwgpio = gpio_chip_hwgpio(desc);
@@ -2682,8 +2699,11 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
(desc_array[i]->gdev->chip == chip));

ret = gpio_chip_get_multiple(chip, mask, bits);
- if (ret)
+ if (ret) {
+ kfree(bits);
+ kfree(mask);
return ret;
+ }

for (j = first; j < i; j++) {
const struct gpio_desc *desc = desc_array[j];
@@ -2695,6 +2715,8 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
value_array[j] = value;
trace_gpio_value(desc_to_gpio(desc), 1, value);
}
+ kfree(bits);
+ kfree(mask);
}
return 0;
}
@@ -2887,14 +2909,30 @@ void gpiod_set_array_value_complex(bool raw, bool can_sleep,

while (i < array_size) {
struct gpio_chip *chip = desc_array[i]->gdev->chip;
- unsigned long mask[BITS_TO_LONGS(chip->ngpio)];
- unsigned long bits[BITS_TO_LONGS(chip->ngpio)];
+ unsigned long *mask;
+ unsigned long *bits;
int count = 0;

+ mask = kmalloc_array(BITS_TO_LONGS(chip->ngpio),
+ sizeof(*mask),
+ can_sleep ? GFP_KERNEL : GFP_ATOMIC);
+
+ if (!mask)
+ return;
+
+ bits = kmalloc_array(BITS_TO_LONGS(chip->ngpio),
+ sizeof(*bits),
+ can_sleep ? GFP_KERNEL : GFP_ATOMIC);
+
+ if (!bits) {
+ kfree(mask);
+ return;
+ }
+
if (!can_sleep)
WARN_ON(chip->can_sleep);

- memset(mask, 0, sizeof(mask));
+ memset(mask, 0, sizeof(*mask));
do {
struct gpio_desc *desc = desc_array[i];
int hwgpio = gpio_chip_hwgpio(desc);
@@ -2925,6 +2963,9 @@ void gpiod_set_array_value_complex(bool raw, bool can_sleep,
/* push collected bits to outputs */
if (count != 0)
gpio_chip_set_multiple(chip, mask, bits);
+
+ kfree(mask);
+ kfree(bits);
}
}

--
2.14.3
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