From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Holler Date: Fri, 25 Jan 2013 18:49:26 +0000 Subject: [PATCH 1/3] semaphore: introduce down_timeout_killable() Message-Id: <1359139768-32294-1-git-send-email-holler@ahsoftware.de> List-Id: References: <50F2A310.5010006@ahsoftware.de> In-Reply-To: <50F2A310.5010006@ahsoftware.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-kernel@vger.kernel.org Cc: linux-fbdev@vger.kernel.org, Florian Tobias Schandinat , Bernie Thompson , Steve Glendinning , Alexander Holler The name says it all, it's like down_timeout() but returns on fatal signals too. Signed-off-by: Alexander Holler --- include/linux/semaphore.h | 2 ++ kernel/semaphore.c | 37 +++++++++++++++++++++++++++++++++++++ 2 files changed, 39 insertions(+) diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h index dc368b8..b508d4d 100644 --- a/include/linux/semaphore.h +++ b/include/linux/semaphore.h @@ -41,6 +41,8 @@ extern int __must_check down_interruptible(struct semaphore *sem); extern int __must_check down_killable(struct semaphore *sem); extern int __must_check down_trylock(struct semaphore *sem); extern int __must_check down_timeout(struct semaphore *sem, long jiffies); +extern int __must_check down_timeout_killable(struct semaphore *sem, + long jiffies); extern void up(struct semaphore *sem); #endif /* __LINUX_SEMAPHORE_H */ diff --git a/kernel/semaphore.c b/kernel/semaphore.c index 4567fc0..4a5e823 100644 --- a/kernel/semaphore.c +++ b/kernel/semaphore.c @@ -37,6 +37,8 @@ static noinline void __down(struct semaphore *sem); static noinline int __down_interruptible(struct semaphore *sem); static noinline int __down_killable(struct semaphore *sem); static noinline int __down_timeout(struct semaphore *sem, long jiffies); +static noinline int __down_timeout_killable(struct semaphore *sem, + long jiffies); static noinline void __up(struct semaphore *sem); /** @@ -169,6 +171,35 @@ int down_timeout(struct semaphore *sem, long jiffies) EXPORT_SYMBOL(down_timeout); /** + * down_timeout_killable - acquire the semaphore within a specified time or + * until a fatal signal arrives. + * @sem: the semaphore to be acquired + * @jiffies: how long to wait before failing + * + * Attempts to acquire the semaphore. If no more tasks are allowed to + * acquire the semaphore, calling this function will put the task to sleep. + * If the semaphore is not released within the specified number of jiffies, + * this function returns -ETIME. If the sleep is interrupted by a fatal signal, + * this function will return -EINTR. If the semaphore is successfully acquired, + * this function returns 0. + */ +int down_timeout_killable(struct semaphore *sem, long jiffies) +{ + unsigned long flags; + int result = 0; + + raw_spin_lock_irqsave(&sem->lock, flags); + if (likely(sem->count > 0)) + sem->count--; + else + result = __down_timeout_killable(sem, jiffies); + raw_spin_unlock_irqrestore(&sem->lock, flags); + + return result; +} +EXPORT_SYMBOL(down_timeout_killable); + +/** * up - release the semaphore * @sem: the semaphore to release * @@ -253,6 +284,12 @@ static noinline int __sched __down_timeout(struct semaphore *sem, long jiffies) return __down_common(sem, TASK_UNINTERRUPTIBLE, jiffies); } +static noinline int __sched __down_timeout_killable(struct semaphore *sem, + long jiffies) +{ + return __down_common(sem, TASK_KILLABLE, jiffies); +} + static noinline void __sched __up(struct semaphore *sem) { struct semaphore_waiter *waiter = list_first_entry(&sem->wait_list, -- 1.7.11.7