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
  91 typedef 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
 106 typedef 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>
 157 extern int atomic_dec_and_lock(atomic_t *atomic, spinlock_t *lock);
 158 #endif
 159
 160 #ifdef CONFIG_SMP
 161 #include <linux/cache.h>
 162
 163 typedef 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
 170 typedef struct {
 171     spinlock_t lock;
 172 } spinlock_cacheline_t;
 173
 174
 175 #endif
 176 #endif /* __LINUX_SPINLOCK_H */