mirror of
https://github.com/openbsd/src.git
synced 2025-01-03 06:45:37 -08:00
Revert the new rwlock implementation for now.
vfs_busy() uses RW_SLEEPFAIL in a broken way. It is possible that the object holding the rwlock is freed while other processes are sleeping on this lock. This worked before by luck and no longer does now since part of the struct needs to be updated after the sleep. vfs_busy() needs to be fixed but that will take a bit of time. OK dlg@
This commit is contained in:
claudio
parent
ac44f26236
commit
4cbd027d54
@ -1,4 +1,4 @@
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/* $OpenBSD: kern_rwlock.c,v 1.51 2024/11/27 01:02:03 dlg Exp $ */
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/* $OpenBSD: kern_rwlock.c,v 1.52 2024/12/03 12:50:16 claudio Exp $ */
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/*
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* Copyright (c) 2002, 2003 Artur Grabowski <art@openbsd.org>
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@ -26,12 +26,10 @@
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#include <sys/atomic.h>
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#include <sys/witness.h>
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#ifdef RWDIAG
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#include <sys/kernel.h> /* for hz */
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#define RW_SLEEP_TMO 10 * hz
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#else
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#define RW_SLEEP_TMO 0
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#endif
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void rw_do_exit(struct rwlock *, unsigned long);
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/* XXX - temporary measure until proc0 is properly aligned */
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#define RW_PROC(p) (((long)p) & ~RWLOCK_MASK)
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/*
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* Other OSes implement more sophisticated mechanism to determine how long the
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@ -42,131 +40,166 @@
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#define RW_SPINS 1000
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#ifdef MULTIPROCESSOR
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#define rw_cas(p, e, n) atomic_cas_ulong(p, e, n)
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#define rw_inc(p) atomic_inc_int(p)
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#define rw_dec(p) atomic_dec_int(p)
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#define rw_cas(p, o, n) (atomic_cas_ulong(p, o, n) != o)
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#else
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static inline unsigned long
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rw_cas(volatile unsigned long *p, unsigned long e, unsigned long n)
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static inline int
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rw_cas(volatile unsigned long *p, unsigned long o, unsigned long n)
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{
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unsigned long o = *p;
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if (o == e)
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if (*p != o)
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return (1);
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*p = n;
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return (o);
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}
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static inline void
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rw_inc(volatile unsigned int *p)
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{
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++(*p);
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}
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static inline void
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rw_dec(volatile unsigned int *p)
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{
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(*p)--;
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return (0);
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}
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#endif
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static int rw_do_enter_read(struct rwlock *, int);
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static void rw_do_exit_read(struct rwlock *, unsigned long);
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static int rw_do_enter_write(struct rwlock *, int);
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static int rw_downgrade(struct rwlock *, int);
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static void rw_exited(struct rwlock *);
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static unsigned long
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rw_self(void)
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{
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unsigned long self = (unsigned long)curproc;
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CLR(self, RWLOCK_MASK);
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SET(self, RWLOCK_WRLOCK);
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return (self);
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}
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/*
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* Magic wand for lock operations. Every operation checks if certain
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* flags are set and if they aren't, it increments the lock with some
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* value (that might need some computing in a few cases). If the operation
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* fails, we need to set certain flags while waiting for the lock.
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*
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* RW_WRITE The lock must be completely empty. We increment it with
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* RWLOCK_WRLOCK and the proc pointer of the holder.
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* Sets RWLOCK_WAIT|RWLOCK_WRWANT while waiting.
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* RW_READ RWLOCK_WRLOCK|RWLOCK_WRWANT may not be set. We increment
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* with RWLOCK_READ_INCR. RWLOCK_WAIT while waiting.
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*/
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static const struct rwlock_op {
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unsigned long inc;
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unsigned long check;
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unsigned long wait_set;
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long proc_mult;
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int wait_prio;
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} rw_ops[] = {
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{ /* RW_WRITE */
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RWLOCK_WRLOCK,
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ULONG_MAX,
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RWLOCK_WAIT | RWLOCK_WRWANT,
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1,
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PLOCK - 4
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},
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{ /* RW_READ */
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RWLOCK_READ_INCR,
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RWLOCK_WRLOCK | RWLOCK_WRWANT,
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RWLOCK_WAIT,
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0,
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PLOCK
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},
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{ /* Sparse Entry. */
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0,
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},
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{ /* RW_DOWNGRADE */
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RWLOCK_READ_INCR - RWLOCK_WRLOCK,
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0,
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0,
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-1,
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PLOCK
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},
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};
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void
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rw_enter_read(struct rwlock *rwl)
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{
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rw_do_enter_read(rwl, 0);
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unsigned long owner = rwl->rwl_owner;
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if (__predict_false((owner & (RWLOCK_WRLOCK | RWLOCK_WRWANT)) ||
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rw_cas(&rwl->rwl_owner, owner, owner + RWLOCK_READ_INCR)))
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rw_enter(rwl, RW_READ);
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else {
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membar_enter_after_atomic();
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WITNESS_CHECKORDER(&rwl->rwl_lock_obj, LOP_NEWORDER, NULL);
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WITNESS_LOCK(&rwl->rwl_lock_obj, 0);
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}
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}
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void
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rw_enter_write(struct rwlock *rwl)
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{
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rw_do_enter_write(rwl, 0);
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struct proc *p = curproc;
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if (__predict_false(rw_cas(&rwl->rwl_owner, 0,
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RW_PROC(p) | RWLOCK_WRLOCK)))
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rw_enter(rwl, RW_WRITE);
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else {
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membar_enter_after_atomic();
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WITNESS_CHECKORDER(&rwl->rwl_lock_obj,
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LOP_EXCLUSIVE | LOP_NEWORDER, NULL);
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WITNESS_LOCK(&rwl->rwl_lock_obj, LOP_EXCLUSIVE);
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}
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}
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void
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rw_exit_read(struct rwlock *rwl)
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{
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/* maybe we're the last one? */
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rw_do_exit_read(rwl, RWLOCK_READ_INCR);
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}
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static void
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rw_do_exit_read(struct rwlock *rwl, unsigned long owner)
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{
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unsigned long decr;
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unsigned long nowner;
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unsigned long owner;
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rw_assert_rdlock(rwl);
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WITNESS_UNLOCK(&rwl->rwl_lock_obj, 0);
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for (;;) {
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decr = owner - RWLOCK_READ_INCR;
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nowner = rw_cas(&rwl->rwl_owner, owner, decr);
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if (owner == nowner)
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break;
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if (__predict_false(ISSET(nowner, RWLOCK_WRLOCK))) {
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panic("%s rwlock %p: exit read on write locked lock"
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" (owner 0x%lx)", rwl->rwl_name, rwl, nowner);
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}
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if (__predict_false(nowner == 0)) {
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panic("%s rwlock %p: exit read on unlocked lock",
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rwl->rwl_name, rwl);
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}
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owner = nowner;
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}
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/* read lock didn't change anything, so no barrier needed? */
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if (decr == 0) {
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/* last one out */
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rw_exited(rwl);
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}
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membar_exit_before_atomic();
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owner = rwl->rwl_owner;
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if (__predict_false((owner & RWLOCK_WAIT) ||
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rw_cas(&rwl->rwl_owner, owner, owner - RWLOCK_READ_INCR)))
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rw_do_exit(rwl, 0);
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}
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void
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rw_exit_write(struct rwlock *rwl)
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{
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unsigned long self = rw_self();
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unsigned long owner;
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rw_assert_wrlock(rwl);
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WITNESS_UNLOCK(&rwl->rwl_lock_obj, LOP_EXCLUSIVE);
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membar_exit_before_atomic();
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owner = rw_cas(&rwl->rwl_owner, self, 0);
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if (__predict_false(owner != self)) {
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panic("%s rwlock %p: exit write when lock not held "
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"(owner 0x%lx, self 0x%lx)", rwl->rwl_name, rwl,
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owner, self);
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owner = rwl->rwl_owner;
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if (__predict_false((owner & RWLOCK_WAIT) ||
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rw_cas(&rwl->rwl_owner, owner, 0)))
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rw_do_exit(rwl, RWLOCK_WRLOCK);
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}
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rw_exited(rwl);
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#ifdef DIAGNOSTIC
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/*
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* Put the diagnostic functions here to keep the main code free
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* from ifdef clutter.
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*/
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static void
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rw_enter_diag(struct rwlock *rwl, int flags)
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{
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switch (flags & RW_OPMASK) {
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case RW_WRITE:
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case RW_READ:
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if (RW_PROC(curproc) == RW_PROC(rwl->rwl_owner))
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panic("rw_enter: %s locking against myself",
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rwl->rwl_name);
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break;
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case RW_DOWNGRADE:
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/*
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* If we're downgrading, we must hold the write lock.
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*/
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if ((rwl->rwl_owner & RWLOCK_WRLOCK) == 0)
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panic("rw_enter: %s downgrade of non-write lock",
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rwl->rwl_name);
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if (RW_PROC(curproc) != RW_PROC(rwl->rwl_owner))
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panic("rw_enter: %s downgrade, not holder",
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rwl->rwl_name);
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break;
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default:
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panic("rw_enter: unknown op 0x%x", flags);
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}
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}
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#else
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#define rw_enter_diag(r, f)
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#endif
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static void
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_rw_init_flags_witness(struct rwlock *rwl, const char *name, int lo_flags,
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const struct lock_type *type)
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{
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rwl->rwl_owner = 0;
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rwl->rwl_waiters = 0;
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rwl->rwl_readers = 0;
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rwl->rwl_name = name;
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#ifdef WITNESS
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@ -190,246 +223,90 @@ _rw_init_flags(struct rwlock *rwl, const char *name, int flags,
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int
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rw_enter(struct rwlock *rwl, int flags)
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{
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int op = flags & RW_OPMASK;
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int error;
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switch (op) {
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case RW_WRITE:
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error = rw_do_enter_write(rwl, flags);
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break;
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case RW_READ:
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error = rw_do_enter_read(rwl, flags);
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break;
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case RW_DOWNGRADE:
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error = rw_downgrade(rwl, flags);
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break;
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default:
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panic("%s rwlock %p: %s unexpected op 0x%x",
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rwl->rwl_name, rwl, __func__, op);
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/* NOTREACHED */
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}
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return (error);
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}
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static int
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rw_do_enter_write(struct rwlock *rwl, int flags)
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{
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unsigned long self = rw_self();
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unsigned long owner;
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int prio;
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int error;
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#ifdef WITNESS
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int lop_flags = LOP_NEWORDER | LOP_EXCLUSIVE;
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if (ISSET(flags, RW_DUPOK))
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lop_flags |= LOP_DUPOK;
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if (!ISSET(flags, RW_NOSLEEP))
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WITNESS_CHECKORDER(&rwl->rwl_lock_obj, lop_flags, NULL);
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#endif
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owner = rw_cas(&rwl->rwl_owner, 0, self);
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if (owner == 0) {
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/* wow, we won. so easy */
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goto locked;
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}
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if (__predict_false(owner == self)) {
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panic("%s rwlock %p: enter write deadlock",
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rwl->rwl_name, rwl);
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}
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const struct rwlock_op *op;
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unsigned long inc, o;
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#ifdef MULTIPROCESSOR
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/*
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* If process holds the kernel lock, then we want to give up on CPU
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* as soon as possible so other processes waiting for the kernel lock
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* can progress. Hence no spinning if we hold the kernel lock.
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*/
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if (!_kernel_lock_held()) {
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int spins;
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unsigned int spin = (_kernel_lock_held()) ? 0 : RW_SPINS;
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#endif
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int error, prio;
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#ifdef WITNESS
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int lop_flags;
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lop_flags = LOP_NEWORDER;
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if (flags & RW_WRITE)
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lop_flags |= LOP_EXCLUSIVE;
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if (flags & RW_DUPOK)
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lop_flags |= LOP_DUPOK;
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if ((flags & RW_NOSLEEP) == 0 && (flags & RW_DOWNGRADE) == 0)
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WITNESS_CHECKORDER(&rwl->rwl_lock_obj, lop_flags, NULL);
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#endif
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op = &rw_ops[(flags & RW_OPMASK) - 1];
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inc = op->inc + RW_PROC(curproc) * op->proc_mult;
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retry:
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while (__predict_false(((o = rwl->rwl_owner) & op->check) != 0)) {
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unsigned long set = o | op->wait_set;
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int do_sleep;
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/* Avoid deadlocks after panic or in DDB */
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if (panicstr || db_active)
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return (0);
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#ifdef MULTIPROCESSOR
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/*
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* It makes sense to try to spin just in case the lock
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* is acquired by writer.
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*/
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for (spins = 0; spins < RW_SPINS; spins++) {
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if ((o & RWLOCK_WRLOCK) && (spin != 0)) {
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spin--;
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CPU_BUSY_CYCLE();
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owner = atomic_load_long(&rwl->rwl_owner);
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if (owner != 0)
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continue;
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owner = rw_cas(&rwl->rwl_owner, 0, self);
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if (owner == 0) {
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/* ok, we won now. */
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goto locked;
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}
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}
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}
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#endif
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if (ISSET(flags, RW_NOSLEEP))
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rw_enter_diag(rwl, flags);
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if (flags & RW_NOSLEEP)
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return (EBUSY);
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prio = PLOCK - 4;
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if (ISSET(flags, RW_INTR))
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prio = op->wait_prio;
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if (flags & RW_INTR)
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prio |= PCATCH;
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sleep_setup(rwl, prio, rwl->rwl_name);
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rw_inc(&rwl->rwl_waiters);
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membar_producer();
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do {
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sleep_setup(&rwl->rwl_waiters, prio, rwl->rwl_name);
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membar_consumer();
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owner = atomic_load_long(&rwl->rwl_owner);
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error = sleep_finish(RW_SLEEP_TMO, owner != 0);
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#ifdef RWDIAG
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if (error == EWOULDBLOCK) {
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printf("%s rwlock %p: %s timeout owner 0x%lx "
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"(self 0x%lx)", rwl->rwl_name, rwl, __func__,
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owner, self);
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db_enter();
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}
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#endif
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if (ISSET(flags, RW_INTR) && (error != 0)) {
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rw_dec(&rwl->rwl_waiters);
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do_sleep = !rw_cas(&rwl->rwl_owner, o, set);
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error = sleep_finish(0, do_sleep);
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if ((flags & RW_INTR) &&
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(error != 0))
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return (error);
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}
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if (ISSET(flags, RW_SLEEPFAIL)) {
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rw_dec(&rwl->rwl_waiters);
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rw_exited(rwl);
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if (flags & RW_SLEEPFAIL)
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return (EAGAIN);
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}
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owner = rw_cas(&rwl->rwl_owner, 0, self);
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} while (owner != 0);
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rw_dec(&rwl->rwl_waiters);
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locked:
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if (__predict_false(rw_cas(&rwl->rwl_owner, o, o + inc)))
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goto retry;
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membar_enter_after_atomic();
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WITNESS_LOCK(&rwl->rwl_lock_obj, lop_flags);
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return (0);
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}
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/*
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* If old lock had RWLOCK_WAIT and RWLOCK_WRLOCK set, it means we
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* downgraded a write lock and had possible read waiter, wake them
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* to let them retry the lock.
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*/
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if (__predict_false((o & (RWLOCK_WRLOCK|RWLOCK_WAIT)) ==
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(RWLOCK_WRLOCK|RWLOCK_WAIT)))
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wakeup(rwl);
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static int
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rw_read_incr(struct rwlock *rwl, unsigned long owner)
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{
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unsigned long incr;
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unsigned long nowner;
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do {
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incr = owner + RWLOCK_READ_INCR;
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nowner = rw_cas(&rwl->rwl_owner, owner, incr);
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if (nowner == owner)
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return (1);
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owner = nowner;
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} while (!ISSET(owner, RWLOCK_WRLOCK));
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return (0);
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}
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static int
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rw_do_enter_read(struct rwlock *rwl, int flags)
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{
|
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unsigned long owner;
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int error;
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int prio;
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#ifdef WITNESS
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int lop_flags = LOP_NEWORDER;
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if (ISSET(flags, RW_DUPOK))
|
||||
lop_flags |= LOP_DUPOK;
|
||||
if (!ISSET(flags, RW_NOSLEEP))
|
||||
WITNESS_CHECKORDER(&rwl->rwl_lock_obj, lop_flags, NULL);
|
||||
#endif
|
||||
|
||||
owner = rw_cas(&rwl->rwl_owner, 0, RWLOCK_READ_INCR);
|
||||
if (owner == 0) {
|
||||
/* ermagerd, we won! */
|
||||
goto locked;
|
||||
}
|
||||
|
||||
if (ISSET(owner, RWLOCK_WRLOCK)) {
|
||||
if (__predict_false(owner == rw_self())) {
|
||||
panic("%s rwlock %p: enter read deadlock",
|
||||
rwl->rwl_name, rwl);
|
||||
}
|
||||
} else if (atomic_load_int(&rwl->rwl_waiters) == 0) {
|
||||
if (rw_read_incr(rwl, owner)) {
|
||||
/* nailed it */
|
||||
goto locked;
|
||||
}
|
||||
}
|
||||
|
||||
if (ISSET(flags, RW_NOSLEEP))
|
||||
return (EBUSY);
|
||||
|
||||
prio = PLOCK;
|
||||
if (ISSET(flags, RW_INTR))
|
||||
prio |= PCATCH;
|
||||
|
||||
rw_inc(&rwl->rwl_readers);
|
||||
membar_producer();
|
||||
do {
|
||||
sleep_setup(&rwl->rwl_readers, prio, rwl->rwl_name);
|
||||
membar_consumer();
|
||||
error = sleep_finish(RW_SLEEP_TMO,
|
||||
atomic_load_int(&rwl->rwl_waiters) > 0 ||
|
||||
ISSET(atomic_load_long(&rwl->rwl_owner), RWLOCK_WRLOCK));
|
||||
#ifdef RWDIAG
|
||||
if (error == EWOULDBLOCK) {
|
||||
printf("%s rwlock %p: %s timeout owner 0x%lx\n",
|
||||
rwl->rwl_name, rwl, __func__, owner);
|
||||
db_enter();
|
||||
}
|
||||
#endif
|
||||
if (ISSET(flags, RW_INTR) && (error != 0))
|
||||
goto fail;
|
||||
if (ISSET(flags, RW_SLEEPFAIL)) {
|
||||
error = EAGAIN;
|
||||
goto fail;
|
||||
}
|
||||
} while (!rw_read_incr(rwl, 0));
|
||||
rw_dec(&rwl->rwl_readers);
|
||||
|
||||
locked:
|
||||
membar_enter_after_atomic();
|
||||
WITNESS_LOCK(&rwl->rwl_lock_obj, lop_flags);
|
||||
|
||||
return (0);
|
||||
fail:
|
||||
rw_dec(&rwl->rwl_readers);
|
||||
return (error);
|
||||
}
|
||||
|
||||
static int
|
||||
rw_downgrade(struct rwlock *rwl, int flags)
|
||||
{
|
||||
unsigned long self = rw_self();
|
||||
unsigned long owner;
|
||||
|
||||
membar_exit_before_atomic();
|
||||
owner = atomic_cas_ulong(&rwl->rwl_owner, self, RWLOCK_READ_INCR);
|
||||
if (__predict_false(owner != self)) {
|
||||
panic("%s rwlock %p: downgrade when lock not held "
|
||||
"(owner 0x%lx, self 0x%lx)", rwl->rwl_name, rwl,
|
||||
owner, self);
|
||||
}
|
||||
|
||||
#ifdef WITNESS
|
||||
{
|
||||
int lop_flags = LOP_NEWORDER;
|
||||
if (ISSET(flags, RW_DUPOK))
|
||||
lop_flags |= LOP_DUPOK;
|
||||
if (flags & RW_DOWNGRADE)
|
||||
WITNESS_DOWNGRADE(&rwl->rwl_lock_obj, lop_flags);
|
||||
}
|
||||
#endif
|
||||
|
||||
membar_consumer();
|
||||
if (atomic_load_int(&rwl->rwl_waiters) == 0 &&
|
||||
atomic_load_int(&rwl->rwl_readers) > 0)
|
||||
wakeup(&rwl->rwl_readers);
|
||||
else
|
||||
WITNESS_LOCK(&rwl->rwl_lock_obj, lop_flags);
|
||||
|
||||
return (0);
|
||||
}
|
||||
@ -437,38 +314,53 @@ rw_downgrade(struct rwlock *rwl, int flags)
|
||||
void
|
||||
rw_exit(struct rwlock *rwl)
|
||||
{
|
||||
unsigned long owner;
|
||||
unsigned long wrlock;
|
||||
|
||||
owner = atomic_load_long(&rwl->rwl_owner);
|
||||
if (__predict_false(owner == 0)) {
|
||||
panic("%s rwlock %p: exit on unlocked lock",
|
||||
rwl->rwl_name, rwl);
|
||||
}
|
||||
/* Avoid deadlocks after panic or in DDB */
|
||||
if (panicstr || db_active)
|
||||
return;
|
||||
|
||||
if (ISSET(owner, RWLOCK_WRLOCK))
|
||||
rw_exit_write(rwl);
|
||||
wrlock = rwl->rwl_owner & RWLOCK_WRLOCK;
|
||||
if (wrlock)
|
||||
rw_assert_wrlock(rwl);
|
||||
else
|
||||
rw_do_exit_read(rwl, owner);
|
||||
rw_assert_rdlock(rwl);
|
||||
WITNESS_UNLOCK(&rwl->rwl_lock_obj, wrlock ? LOP_EXCLUSIVE : 0);
|
||||
|
||||
membar_exit_before_atomic();
|
||||
rw_do_exit(rwl, wrlock);
|
||||
}
|
||||
|
||||
static void
|
||||
rw_exited(struct rwlock *rwl)
|
||||
/* membar_exit_before_atomic() has to precede call of this function. */
|
||||
void
|
||||
rw_do_exit(struct rwlock *rwl, unsigned long wrlock)
|
||||
{
|
||||
membar_consumer();
|
||||
if (atomic_load_int(&rwl->rwl_waiters) > 0)
|
||||
wakeup_one(&rwl->rwl_waiters);
|
||||
else if (atomic_load_int(&rwl->rwl_readers) > 0)
|
||||
wakeup(&rwl->rwl_readers);
|
||||
unsigned long owner, set;
|
||||
|
||||
do {
|
||||
owner = rwl->rwl_owner;
|
||||
if (wrlock)
|
||||
set = 0;
|
||||
else
|
||||
set = (owner - RWLOCK_READ_INCR) &
|
||||
~(RWLOCK_WAIT|RWLOCK_WRWANT);
|
||||
/*
|
||||
* Potential MP race here. If the owner had WRWANT set, we
|
||||
* cleared it and a reader can sneak in before a writer.
|
||||
*/
|
||||
} while (__predict_false(rw_cas(&rwl->rwl_owner, owner, set)));
|
||||
|
||||
if (owner & RWLOCK_WAIT)
|
||||
wakeup(rwl);
|
||||
}
|
||||
|
||||
int
|
||||
rw_status(struct rwlock *rwl)
|
||||
{
|
||||
unsigned long owner;
|
||||
unsigned long owner = rwl->rwl_owner;
|
||||
|
||||
owner = atomic_load_long(&rwl->rwl_owner);
|
||||
if (ISSET(owner, RWLOCK_WRLOCK)) {
|
||||
if (rw_self() == owner)
|
||||
if (owner & RWLOCK_WRLOCK) {
|
||||
if (RW_PROC(curproc) == RW_PROC(owner))
|
||||
return RW_WRITE;
|
||||
else
|
||||
return RW_WRITE_OTHER;
|
||||
@ -488,10 +380,11 @@ rw_assert_wrlock(struct rwlock *rwl)
|
||||
#ifdef WITNESS
|
||||
witness_assert(&rwl->rwl_lock_obj, LA_XLOCKED);
|
||||
#else
|
||||
if (atomic_load_long(&rwl->rwl_owner) != rw_self()) {
|
||||
panic("%s rwlock %p: lock not held by this process",
|
||||
rwl->rwl_name, rwl);
|
||||
}
|
||||
if (!(rwl->rwl_owner & RWLOCK_WRLOCK))
|
||||
panic("%s: lock not held", rwl->rwl_name);
|
||||
|
||||
if (RW_PROC(curproc) != RW_PROC(rwl->rwl_owner))
|
||||
panic("%s: lock not held by this process", rwl->rwl_name);
|
||||
#endif
|
||||
}
|
||||
|
||||
@ -504,8 +397,8 @@ rw_assert_rdlock(struct rwlock *rwl)
|
||||
#ifdef WITNESS
|
||||
witness_assert(&rwl->rwl_lock_obj, LA_SLOCKED);
|
||||
#else
|
||||
if (rw_status(rwl) != RW_READ)
|
||||
panic("%s rwlock %p: lock not shared", rwl->rwl_name, rwl);
|
||||
if (!RW_PROC(rwl->rwl_owner) || (rwl->rwl_owner & RWLOCK_WRLOCK))
|
||||
panic("%s: lock not shared", rwl->rwl_name);
|
||||
#endif
|
||||
}
|
||||
|
||||
@ -520,11 +413,9 @@ rw_assert_anylock(struct rwlock *rwl)
|
||||
#else
|
||||
switch (rw_status(rwl)) {
|
||||
case RW_WRITE_OTHER:
|
||||
panic("%s rwlock %p: lock held by different process "
|
||||
"(self %lx, owner %lx)", rwl->rwl_name, rwl,
|
||||
rw_self(), rwl->rwl_owner);
|
||||
panic("%s: lock held by different process", rwl->rwl_name);
|
||||
case 0:
|
||||
panic("%s rwlock %p: lock not held", rwl->rwl_name, rwl);
|
||||
panic("%s: lock not held", rwl->rwl_name);
|
||||
}
|
||||
#endif
|
||||
}
|
||||
@ -538,8 +429,8 @@ rw_assert_unlocked(struct rwlock *rwl)
|
||||
#ifdef WITNESS
|
||||
witness_assert(&rwl->rwl_lock_obj, LA_UNLOCKED);
|
||||
#else
|
||||
if (atomic_load_long(&rwl->rwl_owner) == rw_self())
|
||||
panic("%s rwlock %p: lock held", rwl->rwl_name, rwl);
|
||||
if (RW_PROC(curproc) == RW_PROC(rwl->rwl_owner))
|
||||
panic("%s: lock held", rwl->rwl_name);
|
||||
#endif
|
||||
}
|
||||
#endif
|
||||
@ -559,7 +450,7 @@ rrw_enter(struct rrwlock *rrwl, int flags)
|
||||
{
|
||||
int rv;
|
||||
|
||||
if (atomic_load_long(&rrwl->rrwl_lock.rwl_owner) == rw_self()) {
|
||||
if (RW_PROC(rrwl->rrwl_lock.rwl_owner) == RW_PROC(curproc)) {
|
||||
if (flags & RW_RECURSEFAIL)
|
||||
return (EDEADLK);
|
||||
else {
|
||||
@ -581,7 +472,7 @@ void
|
||||
rrw_exit(struct rrwlock *rrwl)
|
||||
{
|
||||
|
||||
if (atomic_load_long(&rrwl->rrwl_lock.rwl_owner) == rw_self()) {
|
||||
if (RW_PROC(rrwl->rrwl_lock.rwl_owner) == RW_PROC(curproc)) {
|
||||
KASSERT(rrwl->rrwl_wcnt > 0);
|
||||
rrwl->rrwl_wcnt--;
|
||||
if (rrwl->rrwl_wcnt != 0) {
|
||||
|
||||
@ -1,4 +1,4 @@
|
||||
/* $OpenBSD: rwlock.h,v 1.29 2024/11/27 01:02:03 dlg Exp $ */
|
||||
/* $OpenBSD: rwlock.h,v 1.30 2024/12/03 12:50:16 claudio Exp $ */
|
||||
/*
|
||||
* Copyright (c) 2002 Artur Grabowski <art@openbsd.org>
|
||||
*
|
||||
@ -60,8 +60,6 @@ struct proc;
|
||||
|
||||
struct rwlock {
|
||||
volatile unsigned long rwl_owner;
|
||||
volatile unsigned int rwl_waiters;
|
||||
volatile unsigned int rwl_readers;
|
||||
const char *rwl_name;
|
||||
#ifdef WITNESS
|
||||
struct lock_object rwl_lock_obj;
|
||||
@ -93,12 +91,14 @@ struct rwlock {
|
||||
|
||||
#ifdef WITNESS
|
||||
#define RWLOCK_INITIALIZER(name) \
|
||||
{ 0, 0, 0, name, .rwl_lock_obj = RWLOCK_LO_INITIALIZER(name, 0) }
|
||||
{ 0, name, .rwl_lock_obj = RWLOCK_LO_INITIALIZER(name, 0) }
|
||||
#else
|
||||
#define RWLOCK_INITIALIZER(name) \
|
||||
{ 0, 0, 0, name }
|
||||
{ 0, name }
|
||||
#endif
|
||||
|
||||
#define RWLOCK_WAIT 0x01UL
|
||||
#define RWLOCK_WRWANT 0x02UL
|
||||
#define RWLOCK_WRLOCK 0x04UL
|
||||
#define RWLOCK_MASK 0x07UL
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user