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spinlock: rename parameter lock -> lk

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This commit is contained in:
Russ Cox 2009-07-11 19:26:51 -07:00
parent b8912d999f
commit b121486c3f
1 changed files with 15 additions and 15 deletions
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30
spinlock.c
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@ -9,11 +9,11 @@
#include "spinlock.h" #include "spinlock.h"
void void
initlock(struct spinlock *lock, char *name) initlock(struct spinlock *lk, char *name)
{ {
lock->name = name; lk->name = name;
lock->locked = 0; lk->locked = 0;
lock->cpu = 0xffffffff; lk->cpu = 0xffffffff;
} }
// Acquire the lock. // Acquire the lock.
@ -21,35 +21,35 @@ initlock(struct spinlock *lock, char *name)
// Holding a lock for a long time may cause // Holding a lock for a long time may cause
// other CPUs to waste time spinning to acquire it. // other CPUs to waste time spinning to acquire it.
void void
acquire(struct spinlock *lock) acquire(struct spinlock *lk)
{ {
pushcli(); pushcli();
if(holding(lock)) if(holding(lk))
panic("acquire"); panic("acquire");
// The xchg is atomic. // The xchg is atomic.
// It also serializes, so that reads after acquire are not // It also serializes, so that reads after acquire are not
// reordered before it. // reordered before it.
while(xchg(&lock->locked, 1) == 1) while(xchg(&lk->locked, 1) != 0)
; ;
// Record info about lock acquisition for debugging. // Record info about lock acquisition for debugging.
// The +10 is only so that we can tell the difference // The +10 is only so that we can tell the difference
// between forgetting to initialize lock->cpu // between forgetting to initialize lock->cpu
// and holding a lock on cpu 0. // and holding a lock on cpu 0.
lock->cpu = cpu() + 10; lk->cpu = cpu() + 10;
getcallerpcs(&lock, lock->pcs); getcallerpcs(&lk, lk->pcs);
} }
// Release the lock. // Release the lock.
void void
release(struct spinlock *lock) release(struct spinlock *lk)
{ {
if(!holding(lock)) if(!holding(lk))
panic("release"); panic("release");
lock->pcs[0] = 0; lk->pcs[0] = 0;
lock->cpu = 0xffffffff; lk->cpu = 0xffffffff;
// The xchg serializes, so that reads before release are // The xchg serializes, so that reads before release are
// not reordered after it. The 1996 PentiumPro manual (Volume 3, // not reordered after it. The 1996 PentiumPro manual (Volume 3,
@ -60,7 +60,7 @@ release(struct spinlock *lock)
// after a store. So lock->locked = 0 would work here. // after a store. So lock->locked = 0 would work here.
// The xchg being asm volatile ensures gcc emits it after // The xchg being asm volatile ensures gcc emits it after
// the above assignments (and after the critical section). // the above assignments (and after the critical section).
xchg(&lock->locked, 0); xchg(&lk->locked, 0);
popcli(); popcli();
} }