linux-toradex.git/include/linux/semaphore.h, branch v4.11-rc3 Linux kernel for Apalis and Colibri modules locking, semaphores: Annotate inner lock as raw 2011-09-13T09:11:57+00:00 Thomas Gleixner tglx@linutronix.de 2010-02-24T08:50:22+00:00 8292c9e15c3b069459794a04f5e2cf0d5665ddc4 There is no reason to have the spin_lock protecting the semaphore preemptible on -rt. Annotate it as a raw_spinlock. In mainline this change documents the low level nature of the lock - otherwise there's no functional difference. Lockdep and Sparse checking will work as usual. ( On rt this also solves lockdep complaining about the rt_mutex.wait_lock being not initialized. ) Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> 
There is no reason to have the spin_lock protecting the semaphore
preemptible on -rt. Annotate it as a raw_spinlock.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

( On rt this also solves lockdep complaining about the
  rt_mutex.wait_lock being not initialized. )

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
semaphore: Remove mutex emulation 2010-10-30T10:12:50+00:00 Thomas Gleixner tglx@linutronix.de 2010-09-07T14:34:01+00:00 4882720b267b7b1d1b0ce08334b205f0329d4615 Semaphores used as mutexes have been deprecated for years. Now that all users are either converted to real semaphores or to mutexes remove the cruft. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Hellwig <hch@infradead.org> LKML-Reference: <20100907125057.562399240@linutronix.de> 
Semaphores used as mutexes have been deprecated for years. Now that
all users are either converted to real semaphores or to mutexes remove
the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
LKML-Reference: <20100907125057.562399240@linutronix.de>
semaphore: Add DEFINE_SEMAPHORE 2010-09-08T13:04:10+00:00 Thomas Gleixner tglx@linutronix.de 2010-09-07T12:46:37+00:00 febc88c5948f81114f64c3412011d695aecae233 The full cleanup of init_MUTEX[_LOCKED] and DECLARE_MUTEX has not been done. Some of the users are real semaphores and we should name them as such instead of confusing everyone with "MUTEX". Provide the infrastructure to get finally rid of init_MUTEX[_LOCKED] and DECLARE_MUTEX. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Hellwig <hch@infradead.org> LKML-Reference: <20100907125054.795929962@linutronix.de> 
The full cleanup of init_MUTEX[_LOCKED] and DECLARE_MUTEX has not been
done. Some of the users are real semaphores and we should name them as
such instead of confusing everyone with "MUTEX".

Provide the infrastructure to get finally rid of init_MUTEX[_LOCKED]
and DECLARE_MUTEX.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Hellwig <hch@infradead.org>
LKML-Reference: <20100907125054.795929962@linutronix.de>
Remove __DECLARE_SEMAPHORE_GENERIC 2008-07-24T12:31:21+00:00 Matthew Wilcox matthew@wil.cx 2008-04-23T14:07:27+00:00 b552068999b0b05087c454e525b30b785c79dc9b There are no users of __DECLARE_SEMAPHORE_GENERIC in the kernel Signed-off-by: Matthew Wilcox <willy@linux.intel.com> 
There are no users of __DECLARE_SEMAPHORE_GENERIC in the kernel

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Improve semaphore documentation 2008-04-17T14:43:01+00:00 Matthew Wilcox matthew@wil.cx 2008-04-11T19:23:52+00:00 714493cd5468f42ca3c4f730a9c17c203abd5059 Move documentation from semaphore.h to semaphore.c as requested by Andrew Morton. Also reformat to kernel-doc style and add some more notes about the implementation. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> 
Move documentation from semaphore.h to semaphore.c as requested by
Andrew Morton.  Also reformat to kernel-doc style and add some more
notes about the implementation.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Simplify semaphore implementation 2008-04-17T14:42:54+00:00 Matthew Wilcox matthew@wil.cx 2008-03-14T18:35:22+00:00 b17170b2fac96705db3188f093f89e8e838418e4 By removing the negative values of 'count' and relying on the wait_list to indicate whether we have any waiters, we can simplify the implementation by removing the protection against an unlikely race condition. Thanks to David Howells for his suggestions. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> 
By removing the negative values of 'count' and relying on the wait_list to
indicate whether we have any waiters, we can simplify the implementation
by removing the protection against an unlikely race condition.  Thanks to
David Howells for his suggestions.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Add down_timeout and change ACPI to use it 2008-04-17T14:42:46+00:00 Matthew Wilcox matthew@wil.cx 2008-03-14T17:43:13+00:00 f1241c87a16c4fe9f4f51d6ed3589f031c505e8d ACPI currently emulates a timeout for semaphores with calls to down_trylock and sleep. This produces horrible behaviour in terms of fairness and excessive wakeups. Now that we have a unified semaphore implementation, adding a real down_trylock is almost trivial. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> 
ACPI currently emulates a timeout for semaphores with calls to
down_trylock and sleep.  This produces horrible behaviour in terms of
fairness and excessive wakeups.  Now that we have a unified semaphore
implementation, adding a real down_trylock is almost trivial.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Introduce down_killable() 2008-04-17T14:42:40+00:00 Matthew Wilcox matthew@wil.cx 2008-03-14T17:19:33+00:00 f06d96865861c3dd01520f47e2e61c899db1631f down_killable() is the functional counterpart of mutex_lock_killable. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> 
down_killable() is the functional counterpart of mutex_lock_killable.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Generic semaphore implementation 2008-04-17T14:42:34+00:00 Matthew Wilcox matthew@wil.cx 2008-03-08T02:55:58+00:00 64ac24e738823161693bf791f87adc802cf529ff Semaphores are no longer performance-critical, so a generic C implementation is better for maintainability, debuggability and extensibility. Thanks to Peter Zijlstra for fixing the lockdep warning. Thanks to Harvey Harrison for pointing out that the unlikely() was unnecessary. Signed-off-by: Matthew Wilcox <willy@linux.intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> 
Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility.  Thanks to Peter Zijlstra for fixing the lockdep
warning.  Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>