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Subject[PATCH 11/17] gpiolib: cdev: remove recalculation of offset
Date
Remove recalculation of offset from desc, where desc itself was calculated
from offset.

There is no benefit from the desc -> hwgpio conversion in this context.
The only implicit benefit of the offset -> desc -> hwgpio is
the range check in the offset -> desc, but where desc is required you
still get that, and where desc isn't required it is simpler to perform
the range check directly.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
---
drivers/gpio/gpiolib-cdev.c | 20 +++++++-------------
1 file changed, 7 insertions(+), 13 deletions(-)

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index b2b26dc25051..c86fb9305681 100644
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -832,7 +832,6 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
void __user *ip = (void __user *)arg;
struct gpio_desc *desc;
__u32 offset;
- int hwgpio;

/* We fail any subsequent ioctl():s when the chip is gone */
if (!gc)
@@ -860,12 +859,11 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
return -EFAULT;

+ /* this doubles as a range check on line_offset */
desc = gpiochip_get_desc(gc, lineinfo.line_offset);
if (IS_ERR(desc))
return PTR_ERR(desc);

- hwgpio = gpio_chip_hwgpio(desc);
-
gpio_desc_to_lineinfo(desc, &lineinfo);

if (copy_to_user(ip, &lineinfo, sizeof(lineinfo)))
@@ -881,19 +879,18 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (copy_from_user(&lineinfo, ip, sizeof(lineinfo)))
return -EFAULT;

+ /* this doubles as a range check on line_offset */
desc = gpiochip_get_desc(gc, lineinfo.line_offset);
if (IS_ERR(desc))
return PTR_ERR(desc);

- hwgpio = gpio_chip_hwgpio(desc);
-
- if (test_and_set_bit(hwgpio, cdev->watched_lines))
+ if (test_and_set_bit(lineinfo.line_offset, cdev->watched_lines))
return -EBUSY;

gpio_desc_to_lineinfo(desc, &lineinfo);

if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) {
- clear_bit(hwgpio, cdev->watched_lines);
+ clear_bit(lineinfo.line_offset, cdev->watched_lines);
return -EFAULT;
}

@@ -902,13 +899,10 @@ static long gpio_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
if (copy_from_user(&offset, ip, sizeof(offset)))
return -EFAULT;

- desc = gpiochip_get_desc(gc, offset);
- if (IS_ERR(desc))
- return PTR_ERR(desc);
-
- hwgpio = gpio_chip_hwgpio(desc);
+ if (offset >= cdev->gdev->ngpio)
+ return -EINVAL;

- if (!test_and_clear_bit(hwgpio, cdev->watched_lines))
+ if (!test_and_clear_bit(offset, cdev->watched_lines))
return -EBUSY;

return 0;
--
2.27.0
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