gpiolib: Switch to use compat_need_64bit_alignment_fixup() helper

Use the new compat_need_64bit_alignment_fixup() helper to avoid
ugly ifdeffery in IOCTL compatibility code.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Kent Gibson <warthog618@gmail.com>
Depends-on: 527c412519eb ("compat: add a compat_need_64bit_alignment_fixup() helper")
Link: https://lore.kernel.org/r/20201014103315.82662-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c
index e9faeaf..192721f 100644 (file)
--- a/drivers/gpio/gpiolib-cdev.c
+++ b/drivers/gpio/gpiolib-cdev.c
@@ -1479,21 +1479,10 @@ static __poll_t lineevent_poll(struct file *file,
        return events;
 }
 
-static ssize_t lineevent_get_size(void)
-{
-#if defined(CONFIG_X86_64) && !defined(CONFIG_UML)
-       /* i386 has no padding after 'id' */
-       if (in_ia32_syscall()) {
-               struct compat_gpioeevent_data {
-                       compat_u64      timestamp;
-                       u32             id;
-               };
-
-               return sizeof(struct compat_gpioeevent_data);
-       }
-#endif
-       return sizeof(struct gpioevent_data);
-}
+struct compat_gpioeevent_data {
+       compat_u64      timestamp;
+       u32             id;
+};
 
 static ssize_t lineevent_read(struct file *file,
                              char __user *buf,
@@ -1515,7 +1504,10 @@ static ssize_t lineevent_read(struct file *file,
         * actual sizeof() and pass this as an argument to copy_to_user() to
         * drop unneeded bytes from the output.
         */
-       ge_size = lineevent_get_size();
+       if (compat_need_64bit_alignment_fixup())
+               ge_size = sizeof(struct compat_gpioeevent_data);
+       else
+               ge_size = sizeof(struct gpioevent_data);
        if (count < ge_size)
                return -EINVAL;