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    Subject[PATCH 1/3] semaphore: introduce down_timeout_killable()
    Date
    The name says it all, it's like down_timeout() but returns on fatal signals
    too.

    Signed-off-by: Alexander Holler <holler@ahsoftware.de>
    ---
    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


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