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 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __LINUX_SPINLOCK_H
 #define __LINUX_SPINLOCK_H
 
 /*
  * include/linux/spinlock.h - generic spinlock/rwlock declarations
  *
  * here's the role of the various spinlock/rwlock related include files:
  *
  * on SMP builds:
  *
  *  asm/spinlock_types.h: contains the arch_spinlock_t/arch_rwlock_t and the
  *                        initializers
  *
  *  linux/spinlock_types_raw:
  *            The raw types and initializers
  *  linux/spinlock_types.h:
  *                        defines the generic type and initializers
  *
  *  asm/spinlock.h:       contains the arch_spin_*()/etc. lowlevel
  *                        implementations, mostly inline assembly code
  *
  *   (also included on UP-debug builds:)
  *
  *  linux/spinlock_api_smp.h:
  *                        contains the prototypes for the _spin_*() APIs.
  *
  *  linux/spinlock.h:     builds the final spin_*() APIs.
  *
  * on UP builds:
  *
  *  linux/spinlock_type_up.h:
  *                        contains the generic, simplified UP spinlock type.
  *                        (which is an empty structure on non-debug builds)
  *
  *  linux/spinlock_types_raw:
  *            The raw RT types and initializers
  *  linux/spinlock_types.h:
  *                        defines the generic type and initializers
  *
  *  linux/spinlock_up.h:
  *                        contains the arch_spin_*()/etc. version of UP
  *                        builds. (which are NOPs on non-debug, non-preempt
  *                        builds)
  *
  *   (included on UP-non-debug builds:)
  *
  *  linux/spinlock_api_up.h:
  *                        builds the _spin_*() APIs.
  *
  *  linux/spinlock.h:     builds the final spin_*() APIs.
  */
 
 #include <linux/typecheck.h>
 #include <linux/preempt.h>
 #include <linux/linkage.h>
 #include <linux/compiler.h>
 #include <linux/irqflags.h>
 #include <linux/thread_info.h>
 #include <linux/stringify.h>
 #include <linux/bottom_half.h>
 #include <linux/lockdep.h>
 #include <asm/barrier.h>
 #include <asm/mmiowb.h>
 
 
 /*
  * Must define these before including other files, inline functions need them
  */
 #define LOCK_SECTION_NAME ".text..lock."KBUILD_BASENAME
 
 #define LOCK_SECTION_START(extra)               \
         ".subsection 1\n\t"                     \
         extra                                   \
         ".ifndef " LOCK_SECTION_NAME "\n\t"     \
         LOCK_SECTION_NAME ":\n\t"               \
         ".endif\n"
 
 #define LOCK_SECTION_END                        \
         ".previous\n\t"
 
 #define __lockfunc __section(".spinlock.text")
 
 /*
  * Pull the arch_spinlock_t and arch_rwlock_t definitions:
  */
 #include <linux/spinlock_types.h>
 
 /*
  * Pull the arch_spin*() functions/declarations (UP-nondebug doesn't need them):
  */
 #ifdef CONFIG_SMP
 # include <asm/spinlock.h>
 #else
 # include <linux/spinlock_up.h>
 #endif
 
 #ifdef CONFIG_DEBUG_SPINLOCK
   extern void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
                    struct lock_class_key *key, short inner);
 
 # define raw_spin_lock_init(lock)                   \
 do {                                    \
     static struct lock_class_key __key;             \
                                     \
     __raw_spin_lock_init((lock), #lock, &__key, LD_WAIT_SPIN);  \
 } while (0)
 
 #else
 # define raw_spin_lock_init(lock)               \
     do { *(lock) = __RAW_SPIN_LOCK_UNLOCKED(lock); } while (0)
 #endif
 
 #define raw_spin_is_locked(lock)    arch_spin_is_locked(&(lock)->raw_lock)
 
 #ifdef arch_spin_is_contended
 #define raw_spin_is_contended(lock) arch_spin_is_contended(&(lock)->raw_lock)
 #else
 #define raw_spin_is_contended(lock) (((void)(lock), 0))
 #endif /*arch_spin_is_contended*/
 
 /*
  * smp_mb__after_spinlock() provides the equivalent of a full memory barrier
  * between program-order earlier lock acquisitions and program-order later
  * memory accesses.
  *
  * This guarantees that the following two properties hold:
  *
  *   1) Given the snippet:
  *
  *    { X = 0;  Y = 0; }
  *
  *    CPU0              CPU1
  *
  *    WRITE_ONCE(X, 1);     WRITE_ONCE(Y, 1);
  *    spin_lock(S);         smp_mb();
  *    smp_mb__after_spinlock(); r1 = READ_ONCE(X);
  *    r0 = READ_ONCE(Y);
  *    spin_unlock(S);
  *
  *      it is forbidden that CPU0 does not observe CPU1's store to Y (r0 = 0)
  *      and CPU1 does not observe CPU0's store to X (r1 = 0); see the comments
  *      preceding the call to smp_mb__after_spinlock() in __schedule() and in
  *      try_to_wake_up().
  *
  *   2) Given the snippet:
  *
  *  { X = 0;  Y = 0; }
  *
  *  CPU0        CPU1                CPU2
  *
  *  spin_lock(S);   spin_lock(S);           r1 = READ_ONCE(Y);
  *  WRITE_ONCE(X, 1);   smp_mb__after_spinlock();   smp_rmb();
  *  spin_unlock(S); r0 = READ_ONCE(X);      r2 = READ_ONCE(X);
  *          WRITE_ONCE(Y, 1);
  *          spin_unlock(S);
  *
  *      it is forbidden that CPU0's critical section executes before CPU1's
  *      critical section (r0 = 1), CPU2 observes CPU1's store to Y (r1 = 1)
  *      and CPU2 does not observe CPU0's store to X (r2 = 0); see the comments
  *      preceding the calls to smp_rmb() in try_to_wake_up() for similar
  *      snippets but "projected" onto two CPUs.
  *
  * Property (2) upgrades the lock to an RCsc lock.
  *
  * Since most load-store architectures implement ACQUIRE with an smp_mb() after
  * the LL/SC loop, they need no further barriers. Similarly all our TSO
  * architectures imply an smp_mb() for each atomic instruction and equally don't
  * need more.
  *
  * Architectures that can implement ACQUIRE better need to take care.
  */
 #ifndef smp_mb__after_spinlock
 #define smp_mb__after_spinlock()    kcsan_mb()
 #endif
 
 #ifdef CONFIG_DEBUG_SPINLOCK
  extern void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock);
  extern int do_raw_spin_trylock(raw_spinlock_t *lock);
  extern void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock);
 #else
 static inline void do_raw_spin_lock(raw_spinlock_t *lock) __acquires(lock)
 {
     __acquire(lock);
     arch_spin_lock(&lock->raw_lock);
     mmiowb_spin_lock();
 }
 
 static inline int do_raw_spin_trylock(raw_spinlock_t *lock)
 {
     int ret = arch_spin_trylock(&(lock)->raw_lock);
 
     if (ret)
         mmiowb_spin_lock();
 
     return ret;
 }
 
 static inline void do_raw_spin_unlock(raw_spinlock_t *lock) __releases(lock)
 {
     mmiowb_spin_unlock();
     arch_spin_unlock(&lock->raw_lock);
     __release(lock);
 }
 #endif
 
 /*
  * Define the various spin_lock methods.  Note we define these
  * regardless of whether CONFIG_SMP or CONFIG_PREEMPTION are set. The
  * various methods are defined as nops in the case they are not
  * required.
  */
 #define raw_spin_trylock(lock)  __cond_lock(lock, _raw_spin_trylock(lock))
 
 #define raw_spin_lock(lock) _raw_spin_lock(lock)
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 # define raw_spin_lock_nested(lock, subclass) \
     _raw_spin_lock_nested(lock, subclass)
 
 # define raw_spin_lock_nest_lock(lock, nest_lock)           \
      do {                               \
          typecheck(struct lockdep_map *, &(nest_lock)->dep_map);\
          _raw_spin_lock_nest_lock(lock, &(nest_lock)->dep_map); \
      } while (0)
 #else
 /*
  * Always evaluate the 'subclass' argument to avoid that the compiler
  * warns about set-but-not-used variables when building with
  * CONFIG_DEBUG_LOCK_ALLOC=n and with W=1.
  */
 # define raw_spin_lock_nested(lock, subclass)       \
     _raw_spin_lock(((void)(subclass), (lock)))
 # define raw_spin_lock_nest_lock(lock, nest_lock)   _raw_spin_lock(lock)
 #endif
 
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 
 #define raw_spin_lock_irqsave(lock, flags)          \
     do {                        \
         typecheck(unsigned long, flags);    \
         flags = _raw_spin_lock_irqsave(lock);   \
     } while (0)
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
     do {                                \
         typecheck(unsigned long, flags);            \
         flags = _raw_spin_lock_irqsave_nested(lock, subclass);  \
     } while (0)
 #else
 #define raw_spin_lock_irqsave_nested(lock, flags, subclass)     \
     do {                                \
         typecheck(unsigned long, flags);            \
         flags = _raw_spin_lock_irqsave(lock);           \
     } while (0)
 #endif
 
 #else
 
 #define raw_spin_lock_irqsave(lock, flags)      \
     do {                        \
         typecheck(unsigned long, flags);    \
         _raw_spin_lock_irqsave(lock, flags);    \
     } while (0)
 
 #define raw_spin_lock_irqsave_nested(lock, flags, subclass) \
     raw_spin_lock_irqsave(lock, flags)
 
 #endif
 
 #define raw_spin_lock_irq(lock)     _raw_spin_lock_irq(lock)
 #define raw_spin_lock_bh(lock)      _raw_spin_lock_bh(lock)
 #define raw_spin_unlock(lock)       _raw_spin_unlock(lock)
 #define raw_spin_unlock_irq(lock)   _raw_spin_unlock_irq(lock)
 
 #define raw_spin_unlock_irqrestore(lock, flags)     \
     do {                            \
         typecheck(unsigned long, flags);        \
         _raw_spin_unlock_irqrestore(lock, flags);   \
     } while (0)
 #define raw_spin_unlock_bh(lock)    _raw_spin_unlock_bh(lock)
 
 #define raw_spin_trylock_bh(lock) \
     __cond_lock(lock, _raw_spin_trylock_bh(lock))
 
 #define raw_spin_trylock_irq(lock) \
 ({ \
     local_irq_disable(); \
     raw_spin_trylock(lock) ? \
     1 : ({ local_irq_enable(); 0;  }); \
 })
 
 #define raw_spin_trylock_irqsave(lock, flags) \
 ({ \
     local_irq_save(flags); \
     raw_spin_trylock(lock) ? \
     1 : ({ local_irq_restore(flags); 0; }); \
 })
 
 #ifndef CONFIG_PREEMPT_RT
 /* Include rwlock functions for !RT */
 #include <linux/rwlock.h>
 #endif
 
 /*
  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
  */
 #if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
 # include <linux/spinlock_api_smp.h>
 #else
 # include <linux/spinlock_api_up.h>
 #endif
 
 /* Non PREEMPT_RT kernel, map to raw spinlocks: */
 #ifndef CONFIG_PREEMPT_RT
 
 /*
  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
  */
 
 static __always_inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
 {
     return &lock->rlock;
 }
 
 #ifdef CONFIG_DEBUG_SPINLOCK
 
 # define spin_lock_init(lock)                   \
 do {                                \
     static struct lock_class_key __key;         \
                                 \
     __raw_spin_lock_init(spinlock_check(lock),      \
                  #lock, &__key, LD_WAIT_CONFIG);    \
 } while (0)
 
 #else
 
 # define spin_lock_init(_lock)          \
 do {                        \
     spinlock_check(_lock);          \
     *(_lock) = __SPIN_LOCK_UNLOCKED(_lock); \
 } while (0)
 
 #endif
 
 static __always_inline void spin_lock(spinlock_t *lock)
 {
     raw_spin_lock(&lock->rlock);
 }
 
 static __always_inline void spin_lock_bh(spinlock_t *lock)
 {
     raw_spin_lock_bh(&lock->rlock);
 }
 
 static __always_inline int spin_trylock(spinlock_t *lock)
 {
     return raw_spin_trylock(&lock->rlock);
 }
 
 #define spin_lock_nested(lock, subclass)            \
 do {                                \
     raw_spin_lock_nested(spinlock_check(lock), subclass);   \
 } while (0)
 
 #define spin_lock_nest_lock(lock, nest_lock)                \
 do {                                    \
     raw_spin_lock_nest_lock(spinlock_check(lock), nest_lock);   \
 } while (0)
 
 static __always_inline void spin_lock_irq(spinlock_t *lock)
 {
     raw_spin_lock_irq(&lock->rlock);
 }
 
 #define spin_lock_irqsave(lock, flags)              \
 do {                                \
     raw_spin_lock_irqsave(spinlock_check(lock), flags); \
 } while (0)
 
 #define spin_lock_irqsave_nested(lock, flags, subclass)         \
 do {                                    \
     raw_spin_lock_irqsave_nested(spinlock_check(lock), flags, subclass); \
 } while (0)
 
 static __always_inline void spin_unlock(spinlock_t *lock)
 {
     raw_spin_unlock(&lock->rlock);
 }
 
 static __always_inline void spin_unlock_bh(spinlock_t *lock)
 {
     raw_spin_unlock_bh(&lock->rlock);
 }
 
 static __always_inline void spin_unlock_irq(spinlock_t *lock)
 {
     raw_spin_unlock_irq(&lock->rlock);
 }
 
 static __always_inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)
 {
     raw_spin_unlock_irqrestore(&lock->rlock, flags);
 }
 
 static __always_inline int spin_trylock_bh(spinlock_t *lock)
 {
     return raw_spin_trylock_bh(&lock->rlock);
 }
 
 static __always_inline int spin_trylock_irq(spinlock_t *lock)
 {
     return raw_spin_trylock_irq(&lock->rlock);
 }
 
 #define spin_trylock_irqsave(lock, flags)           \
 ({                              \
     raw_spin_trylock_irqsave(spinlock_check(lock), flags); \
 })
 
 /**
  * spin_is_locked() - Check whether a spinlock is locked.
  * @lock: Pointer to the spinlock.
  *
  * This function is NOT required to provide any memory ordering
  * guarantees; it could be used for debugging purposes or, when
  * additional synchronization is needed, accompanied with other
  * constructs (memory barriers) enforcing the synchronization.
  *
  * Returns: 1 if @lock is locked, 0 otherwise.
  *
  * Note that the function only tells you that the spinlock is
  * seen to be locked, not that it is locked on your CPU.
  *
  * Further, on CONFIG_SMP=n builds with CONFIG_DEBUG_SPINLOCK=n,
  * the return value is always 0 (see include/linux/spinlock_up.h).
  * Therefore you should not rely heavily on the return value.
  */
 static __always_inline int spin_is_locked(spinlock_t *lock)
 {
     return raw_spin_is_locked(&lock->rlock);
 }
 
 static __always_inline int spin_is_contended(spinlock_t *lock)
 {
     return raw_spin_is_contended(&lock->rlock);
 }
 
 #define assert_spin_locked(lock)    assert_raw_spin_locked(&(lock)->rlock)
 
 #else  /* !CONFIG_PREEMPT_RT */
 # include <linux/spinlock_rt.h>
 #endif /* CONFIG_PREEMPT_RT */
 
 /*
  * Pull the atomic_t declaration:
  * (asm-mips/atomic.h needs above definitions)
  */
 #include <linux/atomic.h>
 /**
  * atomic_dec_and_lock - lock on reaching reference count zero
  * @atomic: the atomic counter
  * @lock: the spinlock in question
  *
  * Decrements @atomic by 1.  If the result is 0, returns true and locks
  * @lock.  Returns false for all other cases.
  */
 extern int _atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 #define atomic_dec_and_lock(atomic, lock) \
         __cond_lock(lock, _atomic_dec_and_lock(atomic, lock))
 
 extern int _atomic_dec_and_lock_irqsave(atomic_t *atomic, spinlock_t *lock,
                     unsigned long *flags);
 #define atomic_dec_and_lock_irqsave(atomic, lock, flags) \
         __cond_lock(lock, _atomic_dec_and_lock_irqsave(atomic, lock, &(flags)))
 
 int __alloc_bucket_spinlocks(spinlock_t **locks, unsigned int *lock_mask,
                  size_t max_size, unsigned int cpu_mult,
                  gfp_t gfp, const char *name,
                  struct lock_class_key *key);
 
 #define alloc_bucket_spinlocks(locks, lock_mask, max_size, cpu_mult, gfp)    \
     ({                                   \
         static struct lock_class_key key;                \
         int ret;                             \
                                          \
         ret = __alloc_bucket_spinlocks(locks, lock_mask, max_size,   \
                            cpu_mult, gfp, #locks, &key); \
         ret;                                 \
     })
 
 void free_bucket_spinlocks(spinlock_t *locks);
 
 #endif /* __LINUX_SPINLOCK_H */

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