From e09b41010ba33a20a87472ee821fa407a5b8da36 Mon Sep 17 00:00:00 2001 From: José Pekkarinen Date: Mon, 11 Apr 2016 10:41:07 +0300 Subject: These changes are the raw update to linux-4.4.6-rt14. Kernel sources are taken from kernel.org, and rt patch from the rt wiki download page. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit During the rebasing, the following patch collided: Force tick interrupt and get rid of softirq magic(I70131fb85). Collisions have been removed because its logic was found on the source already. Change-Id: I7f57a4081d9deaa0d9ccfc41a6c8daccdee3b769 Signed-off-by: José Pekkarinen --- kernel/lib/once.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 kernel/lib/once.c (limited to 'kernel/lib/once.c') diff --git a/kernel/lib/once.c b/kernel/lib/once.c new file mode 100644 index 000000000..05c860462 --- /dev/null +++ b/kernel/lib/once.c @@ -0,0 +1,62 @@ +#include +#include +#include +#include + +struct once_work { + struct work_struct work; + struct static_key *key; +}; + +static void once_deferred(struct work_struct *w) +{ + struct once_work *work; + + work = container_of(w, struct once_work, work); + BUG_ON(!static_key_enabled(work->key)); + static_key_slow_dec(work->key); + kfree(work); +} + +static void once_disable_jump(struct static_key *key) +{ + struct once_work *w; + + w = kmalloc(sizeof(*w), GFP_ATOMIC); + if (!w) + return; + + INIT_WORK(&w->work, once_deferred); + w->key = key; + schedule_work(&w->work); +} + +static DEFINE_SPINLOCK(once_lock); + +bool __do_once_start(bool *done, unsigned long *flags) + __acquires(once_lock) +{ + spin_lock_irqsave(&once_lock, *flags); + if (*done) { + spin_unlock_irqrestore(&once_lock, *flags); + /* Keep sparse happy by restoring an even lock count on + * this lock. In case we return here, we don't call into + * __do_once_done but return early in the DO_ONCE() macro. + */ + __acquire(once_lock); + return false; + } + + return true; +} +EXPORT_SYMBOL(__do_once_start); + +void __do_once_done(bool *done, struct static_key *once_key, + unsigned long *flags) + __releases(once_lock) +{ + *done = true; + spin_unlock_irqrestore(&once_lock, *flags); + once_disable_jump(once_key); +} +EXPORT_SYMBOL(__do_once_done); -- cgit 1.2.3-korg