linux-old/include/linux/spinlock.h
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   1#ifndef __LINUX_SPINLOCK_H
   2#define __LINUX_SPINLOCK_H
   3
   4#include <linux/config.h>
   5
   6#include <asm/system.h>
   7
   8/*
   9 * These are the generic versions of the spinlocks and read-write
  10 * locks..
  11 */
  12#define spin_lock_irqsave(lock, flags)          do { local_irq_save(flags);       spin_lock(lock); } while (0)
  13#define spin_lock_irq(lock)                     do { local_irq_disable();         spin_lock(lock); } while (0)
  14#define spin_lock_bh(lock)                      do { local_bh_disable();          spin_lock(lock); } while (0)
  15
  16#define read_lock_irqsave(lock, flags)          do { local_irq_save(flags);       read_lock(lock); } while (0)
  17#define read_lock_irq(lock)                     do { local_irq_disable();         read_lock(lock); } while (0)
  18#define read_lock_bh(lock)                      do { local_bh_disable();          read_lock(lock); } while (0)
  19
  20#define write_lock_irqsave(lock, flags)         do { local_irq_save(flags);      write_lock(lock); } while (0)
  21#define write_lock_irq(lock)                    do { local_irq_disable();        write_lock(lock); } while (0)
  22#define write_lock_bh(lock)                     do { local_bh_disable();         write_lock(lock); } while (0)
  23
  24#define spin_unlock_irqrestore(lock, flags)     do { spin_unlock(lock);  local_irq_restore(flags); } while (0)
  25#define spin_unlock_irq(lock)                   do { spin_unlock(lock);  local_irq_enable();       } while (0)
  26#define spin_unlock_bh(lock)                    do { spin_unlock(lock);  local_bh_enable();        } while (0)
  27
  28#define read_unlock_irqrestore(lock, flags)     do { read_unlock(lock);  local_irq_restore(flags); } while (0)
  29#define read_unlock_irq(lock)                   do { read_unlock(lock);  local_irq_enable();       } while (0)
  30#define read_unlock_bh(lock)                    do { read_unlock(lock);  local_bh_enable();        } while (0)
  31
  32#define write_unlock_irqrestore(lock, flags)    do { write_unlock(lock); local_irq_restore(flags); } while (0)
  33#define write_unlock_irq(lock)                  do { write_unlock(lock); local_irq_enable();       } while (0)
  34#define write_unlock_bh(lock)                   do { write_unlock(lock); local_bh_enable();        } while (0)
  35#define spin_trylock_bh(lock)                   ({ int __r; local_bh_disable();\
  36                                                __r = spin_trylock(lock);      \
  37                                                if (!__r) local_bh_enable();   \
  38                                                __r; })
  39
  40/* Must define these before including other files, inline functions need them */
  41
  42#include <linux/stringify.h>
  43
  44#define LOCK_SECTION_NAME                       \
  45        ".text.lock." __stringify(KBUILD_BASENAME)
  46
  47#define LOCK_SECTION_START(extra)               \
  48        ".subsection 1\n\t"                     \
  49        extra                                   \
  50        ".ifndef " LOCK_SECTION_NAME "\n\t"     \
  51        LOCK_SECTION_NAME ":\n\t"               \
  52        ".endif\n\t"
  53
  54#define LOCK_SECTION_END                        \
  55        ".previous\n\t"
  56
  57#ifdef CONFIG_SMP
  58#include <asm/spinlock.h>
  59
  60#elif !defined(spin_lock_init) /* !SMP and spin_lock_init not previously
  61                                  defined (e.g. by including asm/spinlock.h */
  62
  63#define DEBUG_SPINLOCKS 0       /* 0 == no debugging, 1 == maintain lock state, 2 == full debug */
  64
  65#if (DEBUG_SPINLOCKS < 1)
  66
  67#define atomic_dec_and_lock(atomic,lock) atomic_dec_and_test(atomic)
  68#define ATOMIC_DEC_AND_LOCK
  69
  70/*
  71 * Your basic spinlocks, allowing only a single CPU anywhere
  72 *
  73 * Some older gcc versions had a nasty bug with empty initializers.
  74 * (XXX: could someone please confirm whether egcs 1.1 still has this bug?)
  75 */
  76#if (__GNUC__ > 2 || __GNUC_MINOR__ > 95)
  77  typedef struct { } spinlock_t;
  78  #define SPIN_LOCK_UNLOCKED (spinlock_t) { }
  79#else
  80  typedef struct { int gcc_is_buggy; } spinlock_t;
  81  #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
  82#endif
  83
  84#define spin_lock_init(lock)    do { } while(0)
  85#define spin_lock(lock)         (void)(lock) /* Not "unused variable". */
  86#define spin_is_locked(lock)    (0)
  87#define spin_trylock(lock)      ({1; })
  88#define spin_unlock_wait(lock)  do { } while(0)
  89#define spin_unlock(lock)       do { } while(0)
  90
  91#elif (DEBUG_SPINLOCKS < 2)
  92
  93typedef struct {
  94        volatile unsigned long lock;
  95} spinlock_t;
  96#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
  97
  98#define spin_lock_init(x)       do { (x)->lock = 0; } while (0)
  99#define spin_is_locked(lock)    (test_bit(0,(lock)))
 100#define spin_trylock(lock)      (!test_and_set_bit(0,(lock)))
 101
 102#define spin_lock(x)            do { (x)->lock = 1; } while (0)
 103#define spin_unlock_wait(x)     do { } while (0)
 104#define spin_unlock(x)          do { (x)->lock = 0; } while (0)
 105
 106#else /* (DEBUG_SPINLOCKS >= 2) */
 107
 108typedef struct {
 109        volatile unsigned long lock;
 110        volatile unsigned int babble;
 111        const char *module;
 112} spinlock_t;
 113#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 25, __BASE_FILE__ }
 114
 115#include <linux/kernel.h>
 116
 117#define spin_lock_init(x)       do { (x)->lock = 0; } while (0)
 118#define spin_is_locked(lock)    (test_bit(0,(lock)))
 119#define spin_trylock(lock)      (!test_and_set_bit(0,(lock)))
 120
 121#define spin_lock(x)            do {unsigned long __spinflags; save_flags(__spinflags); cli(); if ((x)->lock&&(x)->babble) {printk("%s:%d: spin_lock(%s:%p) already locked\n", __BASE_FILE__,__LINE__, (x)->module, (x));(x)->babble--;} (x)->lock = 1; restore_flags(__spinflags);} while (0)
 122#define spin_unlock_wait(x)     do {unsigned long __spinflags; save_flags(__spinflags); cli(); if ((x)->lock&&(x)->babble) {printk("%s:%d: spin_unlock_wait(%s:%p) deadlock\n", __BASE_FILE__,__LINE__, (x)->module, (x));(x)->babble--;} restore_flags(__spinflags);} while (0)
 123#define spin_unlock(x)          do {unsigned long __spinflags; save_flags(__spinflags); cli(); if (!(x)->lock&&(x)->babble) {printk("%s:%d: spin_unlock(%s:%p) not locked\n", __BASE_FILE__,__LINE__, (x)->module, (x));(x)->babble--;} (x)->lock = 0; restore_flags(__spinflags);} while (0)
 124
 125#endif  /* DEBUG_SPINLOCKS */
 126
 127/*
 128 * Read-write spinlocks, allowing multiple readers
 129 * but only one writer.
 130 *
 131 * NOTE! it is quite common to have readers in interrupts
 132 * but no interrupt writers. For those circumstances we
 133 * can "mix" irq-safe locks - any writer needs to get a
 134 * irq-safe write-lock, but readers can get non-irqsafe
 135 * read-locks.
 136 *
 137 * Some older gcc versions had a nasty bug with empty initializers.
 138 * (XXX: could someone please confirm whether egcs 1.1 still has this bug?)
 139 */
 140#if (__GNUC__ > 2 || __GNUC_MINOR__ > 91)
 141  typedef struct { } rwlock_t;
 142  #define RW_LOCK_UNLOCKED (rwlock_t) { }
 143#else
 144  typedef struct { int gcc_is_buggy; } rwlock_t;
 145  #define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
 146#endif
 147
 148#define rwlock_init(lock)       do { } while(0)
 149#define read_lock(lock)         (void)(lock) /* Not "unused variable". */
 150#define read_unlock(lock)       (void)(lock) /* Not "unused variable". */
 151#define write_lock(lock)        (void)(lock) /* Not "unused variable". */
 152#define write_unlock(lock)      do { } while(0)
 153
 154#endif /* !SMP */
 155
 156/* "lock on reference count zero" */
 157#ifndef ATOMIC_DEC_AND_LOCK
 158#include <asm/atomic.h>
 159extern int atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 160#endif
 161
 162#ifdef CONFIG_SMP
 163#include <linux/cache.h>
 164
 165typedef union {
 166    spinlock_t lock;
 167    char fill_up[(SMP_CACHE_BYTES)];
 168} spinlock_cacheline_t __attribute__ ((aligned(SMP_CACHE_BYTES)));
 169
 170#else   /* SMP */
 171
 172typedef struct {
 173    spinlock_t lock;
 174} spinlock_cacheline_t;
 175
 176
 177#endif
 178#endif /* __LINUX_SPINLOCK_H */
 179
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