LXR linux-old/include/linux/spinlock.h

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