[PATCH] RTC: rtc-dev tweak for 64-bit kernel
Make rtc-dev work well on 64-bit platforms with 32-bit userland. On those
platforms, users might try to read 32-bit integer value. This patch make
rtc-dev's read() work well for both "int" and "long" size. This tweak is came
from genrtc driver.
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index b1e3e61..6c9ad92 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -58,7 +58,7 @@
unsigned long data;
ssize_t ret;
- if (count < sizeof(unsigned long))
+ if (count != sizeof(unsigned int) && count < sizeof(unsigned long))
return -EINVAL;
add_wait_queue(&rtc->irq_queue, &wait);
@@ -90,11 +90,16 @@
if (ret == 0) {
/* Check for any data updates */
if (rtc->ops->read_callback)
- data = rtc->ops->read_callback(rtc->class_dev.dev, data);
+ data = rtc->ops->read_callback(rtc->class_dev.dev,
+ data);
- ret = put_user(data, (unsigned long __user *)buf);
- if (ret == 0)
- ret = sizeof(unsigned long);
+ if (sizeof(int) != sizeof(long) &&
+ count == sizeof(unsigned int))
+ ret = put_user(data, (unsigned int __user *)buf) ?:
+ sizeof(unsigned int);
+ else
+ ret = put_user(data, (unsigned long __user *)buf) ?:
+ sizeof(unsigned long);
}
return ret;
}