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include/asm-x86/rwsem.h: checkpatch cleanups - formatting only
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Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Joe Perches authored and Ingo Molnar committed Apr 17, 2008
1 parent 0f4fc8c commit 6e5609a
Showing 1 changed file with 86 additions and 83 deletions.
169 changes: 86 additions & 83 deletions include/asm-x86/rwsem.h
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Original file line number Diff line number Diff line change
Expand Up @@ -56,14 +56,16 @@ extern asmregparm struct rw_semaphore *
/*
* the semaphore definition
*/
struct rw_semaphore {
signed long count;

#define RWSEM_UNLOCKED_VALUE 0x00000000
#define RWSEM_ACTIVE_BIAS 0x00000001
#define RWSEM_ACTIVE_MASK 0x0000ffff
#define RWSEM_WAITING_BIAS (-0x00010000)
#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)

struct rw_semaphore {
signed long count;
spinlock_t wait_lock;
struct list_head wait_list;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
Expand All @@ -78,11 +80,13 @@ struct rw_semaphore {
#endif


#define __RWSEM_INITIALIZER(name) \
{ RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) }
#define __RWSEM_INITIALIZER(name) \
{ \
RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait_lock), \
LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) \
}

#define DECLARE_RWSEM(name) \
#define DECLARE_RWSEM(name) \
struct rw_semaphore name = __RWSEM_INITIALIZER(name)

extern void __init_rwsem(struct rw_semaphore *sem, const char *name,
Expand All @@ -100,16 +104,16 @@ do { \
*/
static inline void __down_read(struct rw_semaphore *sem)
{
__asm__ __volatile__(
"# beginning down_read\n\t"
LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value */
" jns 1f\n"
" call call_rwsem_down_read_failed\n"
"1:\n\t"
"# ending down_read\n\t"
: "+m" (sem->count)
: "a" (sem)
: "memory", "cc");
asm volatile("# beginning down_read\n\t"
LOCK_PREFIX " incl (%%eax)\n\t"
/* adds 0x00000001, returns the old value */
" jns 1f\n"
" call call_rwsem_down_read_failed\n"
"1:\n\t"
"# ending down_read\n\t"
: "+m" (sem->count)
: "a" (sem)
: "memory", "cc");
}

/*
Expand All @@ -118,21 +122,20 @@ LOCK_PREFIX " incl (%%eax)\n\t" /* adds 0x00000001, returns the old value
static inline int __down_read_trylock(struct rw_semaphore *sem)
{
__s32 result, tmp;
__asm__ __volatile__(
"# beginning __down_read_trylock\n\t"
" movl %0,%1\n\t"
"1:\n\t"
" movl %1,%2\n\t"
" addl %3,%2\n\t"
" jle 2f\n\t"
LOCK_PREFIX " cmpxchgl %2,%0\n\t"
" jnz 1b\n\t"
"2:\n\t"
"# ending __down_read_trylock\n\t"
: "+m" (sem->count), "=&a" (result), "=&r" (tmp)
: "i" (RWSEM_ACTIVE_READ_BIAS)
: "memory", "cc");
return result>=0 ? 1 : 0;
asm volatile("# beginning __down_read_trylock\n\t"
" movl %0,%1\n\t"
"1:\n\t"
" movl %1,%2\n\t"
" addl %3,%2\n\t"
" jle 2f\n\t"
LOCK_PREFIX " cmpxchgl %2,%0\n\t"
" jnz 1b\n\t"
"2:\n\t"
"# ending __down_read_trylock\n\t"
: "+m" (sem->count), "=&a" (result), "=&r" (tmp)
: "i" (RWSEM_ACTIVE_READ_BIAS)
: "memory", "cc");
return result >= 0 ? 1 : 0;
}

/*
Expand All @@ -143,17 +146,18 @@ static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
int tmp;

tmp = RWSEM_ACTIVE_WRITE_BIAS;
__asm__ __volatile__(
"# beginning down_write\n\t"
LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtract 0x0000ffff, returns the old value */
" testl %%edx,%%edx\n\t" /* was the count 0 before? */
" jz 1f\n"
" call call_rwsem_down_write_failed\n"
"1:\n"
"# ending down_write"
: "+m" (sem->count), "=d" (tmp)
: "a" (sem), "1" (tmp)
: "memory", "cc");
asm volatile("# beginning down_write\n\t"
LOCK_PREFIX " xadd %%edx,(%%eax)\n\t"
/* subtract 0x0000ffff, returns the old value */
" testl %%edx,%%edx\n\t"
/* was the count 0 before? */
" jz 1f\n"
" call call_rwsem_down_write_failed\n"
"1:\n"
"# ending down_write"
: "+m" (sem->count), "=d" (tmp)
: "a" (sem), "1" (tmp)
: "memory", "cc");
}

static inline void __down_write(struct rw_semaphore *sem)
Expand All @@ -167,7 +171,7 @@ static inline void __down_write(struct rw_semaphore *sem)
static inline int __down_write_trylock(struct rw_semaphore *sem)
{
signed long ret = cmpxchg(&sem->count,
RWSEM_UNLOCKED_VALUE,
RWSEM_UNLOCKED_VALUE,
RWSEM_ACTIVE_WRITE_BIAS);
if (ret == RWSEM_UNLOCKED_VALUE)
return 1;
Expand All @@ -180,62 +184,62 @@ static inline int __down_write_trylock(struct rw_semaphore *sem)
static inline void __up_read(struct rw_semaphore *sem)
{
__s32 tmp = -RWSEM_ACTIVE_READ_BIAS;
__asm__ __volatile__(
"# beginning __up_read\n\t"
LOCK_PREFIX " xadd %%edx,(%%eax)\n\t" /* subtracts 1, returns the old value */
" jns 1f\n\t"
" call call_rwsem_wake\n"
"1:\n"
"# ending __up_read\n"
: "+m" (sem->count), "=d" (tmp)
: "a" (sem), "1" (tmp)
: "memory", "cc");
asm volatile("# beginning __up_read\n\t"
LOCK_PREFIX " xadd %%edx,(%%eax)\n\t"
/* subtracts 1, returns the old value */
" jns 1f\n\t"
" call call_rwsem_wake\n"
"1:\n"
"# ending __up_read\n"
: "+m" (sem->count), "=d" (tmp)
: "a" (sem), "1" (tmp)
: "memory", "cc");
}

/*
* unlock after writing
*/
static inline void __up_write(struct rw_semaphore *sem)
{
__asm__ __volatile__(
"# beginning __up_write\n\t"
" movl %2,%%edx\n\t"
LOCK_PREFIX " xaddl %%edx,(%%eax)\n\t" /* tries to transition 0xffff0001 -> 0x00000000 */
" jz 1f\n"
" call call_rwsem_wake\n"
"1:\n\t"
"# ending __up_write\n"
: "+m" (sem->count)
: "a" (sem), "i" (-RWSEM_ACTIVE_WRITE_BIAS)
: "memory", "cc", "edx");
asm volatile("# beginning __up_write\n\t"
" movl %2,%%edx\n\t"
LOCK_PREFIX " xaddl %%edx,(%%eax)\n\t"
/* tries to transition
0xffff0001 -> 0x00000000 */
" jz 1f\n"
" call call_rwsem_wake\n"
"1:\n\t"
"# ending __up_write\n"
: "+m" (sem->count)
: "a" (sem), "i" (-RWSEM_ACTIVE_WRITE_BIAS)
: "memory", "cc", "edx");
}

/*
* downgrade write lock to read lock
*/
static inline void __downgrade_write(struct rw_semaphore *sem)
{
__asm__ __volatile__(
"# beginning __downgrade_write\n\t"
LOCK_PREFIX " addl %2,(%%eax)\n\t" /* transitions 0xZZZZ0001 -> 0xYYYY0001 */
" jns 1f\n\t"
" call call_rwsem_downgrade_wake\n"
"1:\n\t"
"# ending __downgrade_write\n"
: "+m" (sem->count)
: "a" (sem), "i" (-RWSEM_WAITING_BIAS)
: "memory", "cc");
asm volatile("# beginning __downgrade_write\n\t"
LOCK_PREFIX " addl %2,(%%eax)\n\t"
/* transitions 0xZZZZ0001 -> 0xYYYY0001 */
" jns 1f\n\t"
" call call_rwsem_downgrade_wake\n"
"1:\n\t"
"# ending __downgrade_write\n"
: "+m" (sem->count)
: "a" (sem), "i" (-RWSEM_WAITING_BIAS)
: "memory", "cc");
}

/*
* implement atomic add functionality
*/
static inline void rwsem_atomic_add(int delta, struct rw_semaphore *sem)
{
__asm__ __volatile__(
LOCK_PREFIX "addl %1,%0"
: "+m" (sem->count)
: "ir" (delta));
asm volatile(LOCK_PREFIX "addl %1,%0"
: "+m" (sem->count)
: "ir" (delta));
}

/*
Expand All @@ -245,12 +249,11 @@ static inline int rwsem_atomic_update(int delta, struct rw_semaphore *sem)
{
int tmp = delta;

__asm__ __volatile__(
LOCK_PREFIX "xadd %0,%1"
: "+r" (tmp), "+m" (sem->count)
: : "memory");
asm volatile(LOCK_PREFIX "xadd %0,%1"
: "+r" (tmp), "+m" (sem->count)
: : "memory");

return tmp+delta;
return tmp + delta;
}

static inline int rwsem_is_locked(struct rw_semaphore *sem)
Expand Down

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