blaster4385/linux-IllusionX/Documentation/locking, branch v6.12.1

hwspinlock: Introduce hwspin_lock_bust()

2024-05-29T19:52:26Z

When a remoteproc crashes or goes down unexpectedly this can result in a state where locks held by the remoteproc will remain locked possibly resulting in deadlock. This new API hwspin_lock_bust() allows hwspinlock implementers to define a bust operation for freeing previously acquired hwspinlocks after verifying ownership of the acquired lock. Signed-off-by: Richard Maina Reviewed-by: Bjorn Andersson Signed-off-by: Chris Lew Link: https://lore.kernel.org/r/20240529-hwspinlock-bust-v3-1-c8b924ffa5a2@quicinc.com Signed-off-by: Bjorn Andersson

locking/mutex: Clarify that mutex_unlock(), and most other sleeping locks, can still use the lock object after it's unlocked

2024-01-08T08:55:31Z

Clarify the mutex lock lifetime rules a bit more. Signed-off-by: Ingo Molnar Cc: Peter Zijlstra Cc: Jann Horn Cc: Linus Torvalds Link: https://lore.kernel.org/r/20231201121808.GL3818@noisy.programming.kicks-ass.net

locking/mutex: Document that mutex_unlock() is non-atomic

2023-12-01T10:27:43Z

I have seen several cases of attempts to use mutex_unlock() to release an object such that the object can then be freed by another task. This is not safe because mutex_unlock(), in the MUTEX_FLAG_WAITERS && !MUTEX_FLAG_HANDOFF case, accesses the mutex structure after having marked it as unlocked; so mutex_unlock() requires its caller to ensure that the mutex stays alive until mutex_unlock() returns. If MUTEX_FLAG_WAITERS is set and there are real waiters, those waiters have to keep the mutex alive, but we could have a spurious MUTEX_FLAG_WAITERS left if an interruptible/killable waiter bailed between the points where __mutex_unlock_slowpath() did the cmpxchg reading the flags and where it acquired the wait_lock. ( With spinlocks, that kind of code pattern is allowed and, from what I remember, used in several places in the kernel. ) Document this, such a semantic difference between mutexes and spinlocks is fairly unintuitive. [ mingo: Made the changelog a bit more assertive, refined the comments. ] Signed-off-by: Jann Horn Signed-off-by: Ingo Molnar Link: https://lore.kernel.org/r/20231130204817.2031407-1-jannh@google.com

Documentation: Fix typos

2023-08-18T17:29:03Z

Fix typos in Documentation. Signed-off-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20230814212822.193684-4-helgaas@kernel.org Signed-off-by: Jonathan Corbet

Documentation: use capitalization for chapters and acronyms

2023-05-16T18:49:31Z

Use capital letters in acronyms for CD-ROM, FPGA, and PCMCIA. Use capital letter in the first word of chapter headings for Locking, Timers, and "Brief tutorial on CRC computation". Signed-off-by: Randy Dunlap Cc: Moritz Fischer Cc: Wu Hao Cc: Tom Rix Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Cc: Boqun Feng Cc: Dominik Brodowski Cc: Thomas Gleixner Acked-by: Xu Yilun Reviewed-by: Phillip Potter Link: https://lore.kernel.org/r/20230516001518.14514-1-rdunlap@infradead.org Signed-off-by: Jonathan Corbet

docs: locking: refer to the actual existing config names

2023-02-23T19:26:00Z

The config is actually called CONFIG_RT_MUTEXES, not CONFIG_RT_MUTEX. The config CONFIG_LOCK_TORTURE_TEST should be connected by underscore, for the sake of consistent referencing to configs in the kernel documentation. Address those issues. Signed-off-by: Lukas Bulwahn Acked-by: Waiman Long Link: https://lore.kernel.org/r/20230220165749.12850-1-lukas.bulwahn@gmail.com Signed-off-by: Jonathan Corbet

Remove duplicate words inside documentation

2022-09-27T19:21:43Z

I have removed repeated `the` inside the documentation Signed-off-by: Akhil Raj Link: https://lore.kernel.org/r/20220827145359.32599-1-lf32.dev@gmail.com Signed-off-by: Jonathan Corbet

Documentation: Fix duplicate statement about raw_spinlock_t type

2022-03-25T19:30:08Z

Unless it was duplicate on purpose, to emphasize that a raw_spinlock_t is always a spinning lock regardless of PREEMPT_RT or kernel config, it's a bit odd that this text is duplicate. So, this patch just clean it up, keeping the consistency with the other sections of the text. Cc: Thomas Gleixner Fixes: 919e9e6395cf ("Documentation: Add lock ordering and nesting documentation") Signed-off-by: Guilherme G. Piccoli Link: https://lore.kernel.org/r/20220321144133.49804-1-gpiccoli@igalia.com Signed-off-by: Jonathan Corbet

Documentation/locking/locktypes: Fix PREEMPT_RT _bh() description

2022-03-04T17:13:19Z

With PREEMPT_RT the _bh() version of a spinlock leaves preemption enabled, align the doc to say that instead of the opposite. Reported-by: Leah Leshchinsky Signed-off-by: Andrew Halaney Reviewed-by: Boqun Feng Link: https://lore.kernel.org/r/20220224212312.2601153-1-ahalaney@redhat.com Signed-off-by: Jonathan Corbet

Documentation/locking/locktypes: Update migrate_disable() bits.

2021-11-30T14:40:31Z

The initial implementation of migrate_disable() for mainline was a wrapper around preempt_disable(). RT kernels substituted this with a real migrate disable implementation. Later on mainline gained true migrate disable support, but the documentation was not updated. Update the documentation, remove the claims about migrate_disable() mapping to preempt_disable() on non-PREEMPT_RT kernels. Fixes: 74d862b682f51 ("sched: Make migrate_disable/enable() independent of RT") Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20211127163200.10466-2-bigeasy@linutronix.de