diff options
| author | Jiri Kosina <jkosina@suse.cz> | 2007-11-28 16:22:03 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-11-29 09:24:54 -0800 |
| commit | 8853c202b4a91713dbfb4d9b6e1c87cc2aa12392 (patch) | |
| tree | a6c9621d3067eebc17c2ce53fa45e7513ee832a6 | |
| parent | 08b633070ad5fa17a837428a601c32cf3db6aafd (diff) | |
RTC: convert mutex to bitfield
RTC code is using mutex to assure exclusive access to /dev/rtc. This is
however wrong usage, as it leaves the mutex locked when returning into
userspace, which is unacceptable.
Convert rtc->char_lock into bit operation.
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | drivers/rtc/interface.c | 4 | ||||
| -rw-r--r-- | drivers/rtc/rtc-dev.c | 12 | ||||
| -rw-r--r-- | include/linux/rtc.h | 5 |
3 files changed, 10 insertions, 11 deletions
diff --git a/drivers/rtc/interface.c b/drivers/rtc/interface.c index de0da545c7a..a4f56e95cf9 100644 --- a/drivers/rtc/interface.c +++ b/drivers/rtc/interface.c @@ -293,7 +293,7 @@ int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) return -EINVAL; /* Cannot register while the char dev is in use */ - if (!(mutex_trylock(&rtc->char_lock))) + if (test_and_set_bit(RTC_DEV_BUSY, &rtc->flags)) return -EBUSY; spin_lock_irq(&rtc->irq_task_lock); @@ -303,7 +303,7 @@ int rtc_irq_register(struct rtc_device *rtc, struct rtc_task *task) } spin_unlock_irq(&rtc->irq_task_lock); - mutex_unlock(&rtc->char_lock); + clear_bit(RTC_DEV_BUSY, &rtc->flags); return retval; } diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c index 814583bd2fe..ae1bf177d62 100644 --- a/drivers/rtc/rtc-dev.c +++ b/drivers/rtc/rtc-dev.c @@ -26,10 +26,7 @@ static int rtc_dev_open(struct inode *inode, struct file *file) struct rtc_device, char_dev); const struct rtc_class_ops *ops = rtc->ops; - /* We keep the lock as long as the device is in use - * and return immediately if busy - */ - if (!(mutex_trylock(&rtc->char_lock))) + if (test_and_set_bit(RTC_DEV_BUSY, &rtc->flags)) return -EBUSY; file->private_data = rtc; @@ -43,8 +40,8 @@ static int rtc_dev_open(struct inode *inode, struct file *file) return 0; } - /* something has gone wrong, release the lock */ - mutex_unlock(&rtc->char_lock); + /* something has gone wrong */ + clear_bit(RTC_DEV_BUSY, &rtc->flags); return err; } @@ -405,7 +402,7 @@ static int rtc_dev_release(struct inode *inode, struct file *file) if (rtc->ops->release) rtc->ops->release(rtc->dev.parent); - mutex_unlock(&rtc->char_lock); + clear_bit(RTC_DEV_BUSY, &rtc->flags); return 0; } @@ -440,7 +437,6 @@ void rtc_dev_prepare(struct rtc_device *rtc) rtc->dev.devt = MKDEV(MAJOR(rtc_devt), rtc->id); - mutex_init(&rtc->char_lock); #ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL INIT_WORK(&rtc->uie_task, rtc_uie_task); setup_timer(&rtc->uie_timer, rtc_uie_timer, (unsigned long)rtc); diff --git a/include/linux/rtc.h b/include/linux/rtc.h index 6d5e4a46781..f2d0d152772 100644 --- a/include/linux/rtc.h +++ b/include/linux/rtc.h @@ -133,6 +133,9 @@ struct rtc_class_ops { #define RTC_DEVICE_NAME_SIZE 20 struct rtc_task; +/* flags */ +#define RTC_DEV_BUSY 0 + struct rtc_device { struct device dev; @@ -145,7 +148,7 @@ struct rtc_device struct mutex ops_lock; struct cdev char_dev; - struct mutex char_lock; + unsigned long flags; unsigned long irq_data; spinlock_t irq_lock; |