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48380368 |
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28-Mar-2023 |
Peter Zijlstra <peterz@infradead.org> |
Change DEFINE_SEMAPHORE() to take a number argument Fundamentally semaphores are a counted primitive, but DEFINE_SEMAPHORE() does not expose this and explicitly creates a binary semaphore. Change DEFINE_SEMAPHORE() to take a number argument and use that in the few places that open-coded it using __SEMAPHORE_INITIALIZER(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [mcgrof: add some tribal knowledge about why some folks prefer binary sempahores over mutexes] Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
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3e456101 |
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01-Jun-2019 |
Thomas Gleixner <tglx@linutronix.de> |
treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 436 Based on 1 normalized pattern(s): distributed under the terms of the gnu gpl version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 2 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Armijn Hemel <armijn@tjaldur.nl> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.032570679@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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2dd6fd2e |
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31-Jan-2018 |
Tycho Andersen <tycho@tycho.pizza> |
locking/semaphore: Update the file path in documentation While reading this header I noticed that the locking stuff has moved to kernel/locking/*, so update the path in semaphore.h to point to that. Signed-off-by: Tycho Andersen <tycho@tycho.ws> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20180201114119.1090-1-tycho@tycho.ws Signed-off-by: Ingo Molnar <mingo@kernel.org>
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8292c9e1 |
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24-Feb-2010 |
Thomas Gleixner <tglx@linutronix.de> |
locking, semaphores: Annotate inner lock as raw 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>
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4882720b |
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07-Sep-2010 |
Thomas Gleixner <tglx@linutronix.de> |
semaphore: Remove mutex emulation 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>
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febc88c5 |
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07-Sep-2010 |
Thomas Gleixner <tglx@linutronix.de> |
semaphore: Add DEFINE_SEMAPHORE 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>
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b5520689 |
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23-Apr-2008 |
Matthew Wilcox <willy@infradead.org> |
Remove __DECLARE_SEMAPHORE_GENERIC There are no users of __DECLARE_SEMAPHORE_GENERIC in the kernel Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
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714493cd |
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11-Apr-2008 |
Matthew Wilcox <willy@infradead.org> |
Improve semaphore documentation 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>
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b17170b2 |
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14-Mar-2008 |
Matthew Wilcox <willy@infradead.org> |
Simplify semaphore implementation 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>
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f1241c87 |
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14-Mar-2008 |
Matthew Wilcox <willy@infradead.org> |
Add down_timeout and change ACPI to use it 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>
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f06d9686 |
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14-Mar-2008 |
Matthew Wilcox <willy@infradead.org> |
Introduce down_killable() down_killable() is the functional counterpart of mutex_lock_killable. Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
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64ac24e7 |
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07-Mar-2008 |
Matthew Wilcox <willy@infradead.org> |
Generic semaphore implementation 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>
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