cregit-Linux how code gets into the kernel

Release 4.12 include/linux/bit_spinlock.h

Directory: include/linux
#ifndef __LINUX_BIT_SPINLOCK_H

#define __LINUX_BIT_SPINLOCK_H

#include <linux/kernel.h>
#include <linux/preempt.h>
#include <linux/atomic.h>
#include <linux/bug.h>

/*
 *  bit-based spin_lock()
 *
 * Don't use this unless you really need to: spin_lock() and spin_unlock()
 * are significantly faster.
 */

static inline void bit_spin_lock(int bitnum, unsigned long *addr) { /* * Assuming the lock is uncontended, this never enters * the body of the outer loop. If it is contended, then * within the inner loop a non-atomic test is used to * busywait with less bus contention for a good time to * attempt to acquire the lock bit. */ preempt_disable(); #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) while (unlikely(test_and_set_bit_lock(bitnum, addr))) { preempt_enable(); do { cpu_relax(); } while (test_bit(bitnum, addr)); preempt_disable(); } #endif __acquire(bitlock); }

Contributors

PersonTokensPropCommitsCommitProp
Ingo Molnar5879.45%133.33%
Linus Torvalds1115.07%133.33%
Nicholas Piggin45.48%133.33%
Total73100.00%3100.00%

/* * Return true if it was acquired */
static inline int bit_spin_trylock(int bitnum, unsigned long *addr) { preempt_disable(); #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) if (unlikely(test_and_set_bit_lock(bitnum, addr))) { preempt_enable(); return 0; } #endif __acquire(bitlock); return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Ingo Molnar5593.22%150.00%
Nicholas Piggin46.78%150.00%
Total59100.00%2100.00%

/* * bit-based spin_unlock() */
static inline void bit_spin_unlock(int bitnum, unsigned long *addr) { #ifdef CONFIG_DEBUG_SPINLOCK BUG_ON(!test_bit(bitnum, addr)); #endif #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) clear_bit_unlock(bitnum, addr); #endif preempt_enable(); __release(bitlock); }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin3457.63%150.00%
Ingo Molnar2542.37%150.00%
Total59100.00%2100.00%

/* * bit-based spin_unlock() * non-atomic version, which can be used eg. if the bit lock itself is * protecting the rest of the flags in the word. */
static inline void __bit_spin_unlock(int bitnum, unsigned long *addr) { #ifdef CONFIG_DEBUG_SPINLOCK BUG_ON(!test_bit(bitnum, addr)); #endif #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) __clear_bit_unlock(bitnum, addr); #endif preempt_enable(); __release(bitlock); }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin3152.54%150.00%
Ingo Molnar2847.46%150.00%
Total59100.00%2100.00%

/* * Return true if the lock is held. */
static inline int bit_spin_is_locked(int bitnum, unsigned long *addr) { #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) return test_bit(bitnum, addr); #elif defined CONFIG_PREEMPT_COUNT return preempt_count(); #else return 1; #endif }

Contributors

PersonTokensPropCommitsCommitProp
Ingo Molnar4897.96%150.00%
Frédéric Weisbecker12.04%150.00%
Total49100.00%2100.00%

#endif /* __LINUX_BIT_SPINLOCK_H */

Overall Contributors

PersonTokensPropCommitsCommitProp
Ingo Molnar22769.85%114.29%
Nicholas Piggin8225.23%228.57%
Linus Torvalds113.38%114.29%
Paul Gortmaker30.92%114.29%
Frédéric Weisbecker10.31%114.29%
Arun Sharma10.31%114.29%
Total325100.00%7100.00%
Directory: include/linux
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