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2024-11-11rust: helpers: Avoid raw_spin_lock initialization for PREEMPT_RTEder Zulian1-8/+7
When PREEMPT_RT=y, spin locks are mapped to rt_mutex types, so using spinlock_check() + __raw_spin_lock_init() to initialize spin locks is incorrect, and would cause build errors. Introduce __spin_lock_init() to initialize a spin lock with lockdep rquired information for PREEMPT_RT builds, and use it in the Rust helper. Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.") Closes: https://lore.kernel.org/oe-kbuild-all/202409251238.vetlgXE9-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Eder Zulian <ezulian@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20241107163223.2092690-2-ezulian@redhat.com
2024-10-24locking/rt: Remove one __cond_lock() in RT's spin_trylock_irqsave()Sebastian Andrzej Siewior1-4/+1
spin_trylock_irqsave() has a __cond_lock() wrapper which points to __spin_trylock_irqsave(). The function then invokes spin_trylock() which has another __cond_lock() finally pointing to rt_spin_trylock(). The compiler has no problem to parse this but sparse does not recognise that users of spin_trylock_irqsave() acquire a conditional lock and complains. Remove one layer of __cond_lock() so that sparse recognises conditional locking. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240812104200.2239232-3-bigeasy@linutronix.de
2024-10-24locking/rt: Add sparse annotation PREEMPT_RT's sleeping locks.Sebastian Andrzej Siewior1-4/+4
The sleeping locks on PREEMPT_RT (rt_spin_lock() and friends) lack sparse annotation. Therefore a missing spin_unlock() won't be spotted by sparse in a PREEMPT_RT build while it is noticed on a !PREEMPT_RT build. Add the __acquires/__releases macros to the lock/ unlock functions. The trylock functions already use the __cond_lock() wrapper. Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20240812104200.2239232-2-bigeasy@linutronix.de
2022-09-15locking: Detect includes rwlock.h outside of spinlock.hSebastian Andrzej Siewior1-1/+1
From: Michael S. Tsirkin <mst@redhat.com> The check for __LINUX_SPINLOCK_H within rwlock.h (and other files) detects the direct include of the header file if it is at the very beginning of the include section. If it is listed later then chances are high that spinlock.h was already included (including rwlock.h) and the additional listing of rwlock.h will not cause any failure. On PREEMPT_RT this additional rwlock.h will lead to compile failures since it uses a different rwlock implementation. Add __LINUX_INSIDE_SPINLOCK_H to spinlock.h and check for this instead of __LINUX_SPINLOCK_H to detect wrong includes. This will help detect direct includes of rwlock.h with without PREEMPT_RT enabled. [ bigeasy: add remaining __LINUX_SPINLOCK_H user and rewrite commit description. ] Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/YweemHxJx7O8rjBx@linutronix.de
2021-08-17locking/spinlock/rt: Prepare for RT local_lockThomas Gleixner1-8/+16
Add the static and runtime initializer mechanics to support the RT variant of local_lock, which requires the lock type in the lockdep map to be set to LD_LOCK_PERCPU. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210815211305.967526724@linutronix.de
2021-08-17locking/rwlock: Provide RT variantThomas Gleixner1-0/+2
Similar to rw_semaphores, on RT the rwlock substitution is not writer fair, because it's not feasible to have a writer inherit its priority to multiple readers. Readers blocked on a writer follow the normal rules of priority inheritance. Like RT spinlocks, RT rwlocks are state preserving across the slow lock operations (contended case). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210815211303.882793524@linutronix.de
2021-08-17locking/spinlock: Provide RT variant header: <linux/spinlock_rt.h>Thomas Gleixner1-0/+149
Provide the necessary wrappers around the actual rtmutex based spinlock implementation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20210815211303.712897671@linutronix.de