linux-toradex.git/include/linux/semaphore.h, branch v2.6.26-rc5 Linux kernel for Apalis and Colibri modules 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>