Hi,
This also happened the last time I touched rw_downgrade(), and I backed out
the change then, but both times I don't see the bug. I have some questions:
- Are you running DIAGNOSTIC and/or LOCKDEBUG? I would be very interested
to see what happens with a LOCKDEBUG kernel here.
- Do you have an ATI Radeon graphics chip?
- Are you using ZFS?
Thanks,
Andrew
On Mon, Jan 20, 2020 at 12:41:37PM +0900, Ryo ONODERA wrote:
> Hi,
>
> After this commit, the kernel stalls just before root file system
> will be found on my NetBSD/amd64 laptop.
>
> Reverting
> src/sys/kern/kern_rwlock.c to r1.60
> and
> src/sys/sys/rwlock.h to r1.12
> in latest -current tree and I can get the kernel that works like
> before.
>
> And on another laptop, the problematic kernel stalls before root file
> system detection like my laptop.
>
> It may be universal problem.
>
> Could you take a look at this problem?
>
> Thank you.
>
> "Andrew Doran" <a...@netbsd.org> writes:
>
> > Module Name: src
> > Committed By: ad
> > Date: Sun Jan 19 18:34:24 UTC 2020
> >
> > Modified Files:
> > src/sys/kern: kern_rwlock.c
> > src/sys/sys: rwlock.h
> >
> > Log Message:
> > Tidy rwlocks a bit, no functional change intended. Mainly:
> >
> > - rw_downgrade(): do it in a for () loop like all the others.
> > - Explicitly carry around RW_NODEBUG - don't be lazy.
> > - Remove pointless macros.
> > - Don't make assertions conditional on LOCKDEBUG, there's no reason.
> > - Make space for a new flag bit (not added yet).
> >
> >
> > To generate a diff of this commit:
> > cvs rdiff -u -r1.60 -r1.61 src/sys/kern/kern_rwlock.c
> > cvs rdiff -u -r1.12 -r1.13 src/sys/sys/rwlock.h
> >
> > Please note that diffs are not public domain; they are subject to the
> > copyright notices on the relevant files.
> >
> > Modified files:
> >
> > Index: src/sys/kern/kern_rwlock.c
> > diff -u src/sys/kern/kern_rwlock.c:1.60 src/sys/kern/kern_rwlock.c:1.61
> > --- src/sys/kern/kern_rwlock.c:1.60 Sun Jan 12 18:37:10 2020
> > +++ src/sys/kern/kern_rwlock.c Sun Jan 19 18:34:24 2020
> > @@ -1,4 +1,4 @@
> > -/* $NetBSD: kern_rwlock.c,v 1.60 2020/01/12 18:37:10 ad Exp $ */
> > +/* $NetBSD: kern_rwlock.c,v 1.61 2020/01/19 18:34:24 ad Exp $ */
> >
> > /*-
> > * Copyright (c) 2002, 2006, 2007, 2008, 2009, 2019, 2020
> > @@ -39,7 +39,9 @@
> > */
> >
> > #include <sys/cdefs.h>
> > -__KERNEL_RCSID(0, "$NetBSD: kern_rwlock.c,v 1.60 2020/01/12 18:37:10 ad
> > Exp $");
> > +__KERNEL_RCSID(0, "$NetBSD: kern_rwlock.c,v 1.61 2020/01/19 18:34:24 ad
> > Exp $");
> > +
> > +#include "opt_lockdebug.h"
> >
> > #define __RWLOCK_PRIVATE
> >
> > @@ -63,58 +65,32 @@ __KERNEL_RCSID(0, "$NetBSD: kern_rwlock.
> > * LOCKDEBUG
> > */
> >
> > -#if defined(LOCKDEBUG)
> > -
> > -#define RW_WANTLOCK(rw, op)
> > \
> > - LOCKDEBUG_WANTLOCK(RW_DEBUG_P(rw), (rw), \
> > - (uintptr_t)__builtin_return_address(0), op == RW_READER);
> > -#define RW_LOCKED(rw, op)
> > \
> > - LOCKDEBUG_LOCKED(RW_DEBUG_P(rw), (rw), NULL, \
> > - (uintptr_t)__builtin_return_address(0), op == RW_READER);
> > -#define RW_UNLOCKED(rw, op)
> > \
> > - LOCKDEBUG_UNLOCKED(RW_DEBUG_P(rw), (rw), \
> > - (uintptr_t)__builtin_return_address(0), op == RW_READER);
> > -#define RW_DASSERT(rw, cond)
> > \
> > -do {
> > \
> > - if (__predict_false(!(cond))) \
> > - rw_abort(__func__, __LINE__, rw, "assertion failed: " #cond);\
> > -} while (/* CONSTCOND */ 0);
> > -
> > -#else /* LOCKDEBUG */
> > -
> > -#define RW_WANTLOCK(rw, op) /* nothing */
> > -#define RW_LOCKED(rw, op) /* nothing */
> > -#define RW_UNLOCKED(rw, op) /* nothing */
> > -#define RW_DASSERT(rw, cond) /* nothing */
> > +#define RW_DEBUG_P(rw) (((rw)->rw_owner & RW_NODEBUG) == 0)
> >
> > -#endif /* LOCKDEBUG */
> > +#define RW_WANTLOCK(rw, op) \
> > + LOCKDEBUG_WANTLOCK(RW_DEBUG_P(rw), (rw), \
> > + (uintptr_t)__builtin_return_address(0), op == RW_READER);
> > +#define RW_LOCKED(rw, op) \
> > + LOCKDEBUG_LOCKED(RW_DEBUG_P(rw), (rw), NULL, \
> > + (uintptr_t)__builtin_return_address(0), op == RW_READER);
> > +#define RW_UNLOCKED(rw, op) \
> > + LOCKDEBUG_UNLOCKED(RW_DEBUG_P(rw), (rw), \
> > + (uintptr_t)__builtin_return_address(0), op == RW_READER);
> >
> > /*
> > * DIAGNOSTIC
> > */
> >
> > #if defined(DIAGNOSTIC)
> > -
> > -#define RW_ASSERT(rw, cond)
> > \
> > -do {
> > \
> > - if (__predict_false(!(cond))) \
> > +#define RW_ASSERT(rw, cond) \
> > +do { \
> > + if (__predict_false(!(cond))) \
> > rw_abort(__func__, __LINE__, rw, "assertion failed: " #cond);\
> > } while (/* CONSTCOND */ 0)
> > -
> > #else
> > -
> > #define RW_ASSERT(rw, cond) /* nothing */
> > -
> > #endif /* DIAGNOSTIC */
> >
> > -#define RW_SETDEBUG(rw, on) ((rw)->rw_owner |= (on) ? 0 :
> > RW_NODEBUG)
> > -#define RW_DEBUG_P(rw) (((rw)->rw_owner & RW_NODEBUG)
> > == 0)
> > -#if defined(LOCKDEBUG)
> > -#define RW_INHERITDEBUG(n, o) (n) |= (o) & RW_NODEBUG
> > -#else /* defined(LOCKDEBUG) */
> > -#define RW_INHERITDEBUG(n, o) /* nothing */
> > -#endif /* defined(LOCKDEBUG) */
> > -
> > /*
> > * Memory barriers.
> > */
> > @@ -128,29 +104,6 @@ do {
> > \
> > #define RW_MEMBAR_PRODUCER() membar_producer()
> > #endif
> >
> > -static void rw_abort(const char *, size_t, krwlock_t *, const char
> > *);
> > -static void rw_dump(const volatile void *, lockop_printer_t);
> > -static lwp_t *rw_owner(wchan_t);
> > -
> > -static inline uintptr_t
> > -rw_cas(krwlock_t *rw, uintptr_t o, uintptr_t n)
> > -{
> > -
> > - RW_INHERITDEBUG(n, o);
> > - return (uintptr_t)atomic_cas_ptr((volatile void *)&rw->rw_owner,
> > - (void *)o, (void *)n);
> > -}
> > -
> > -static inline void
> > -rw_swap(krwlock_t *rw, uintptr_t o, uintptr_t n)
> > -{
> > -
> > - RW_INHERITDEBUG(n, o);
> > - n = (uintptr_t)atomic_swap_ptr((volatile void *)&rw->rw_owner,
> > - (void *)n);
> > - RW_DASSERT(rw, n == o);
> > -}
> > -
> > /*
> > * For platforms that do not provide stubs, or for the LOCKDEBUG case.
> > */
> > @@ -164,6 +117,10 @@ __strong_alias(rw_exit,rw_vector_exit);
> > __strong_alias(rw_tryenter,rw_vector_tryenter);
> > #endif
> >
> > +static void rw_abort(const char *, size_t, krwlock_t *, const char
> > *);
> > +static void rw_dump(const volatile void *, lockop_printer_t);
> > +static lwp_t *rw_owner(wchan_t);
> > +
> > lockops_t rwlock_lockops = {
> > .lo_name = "Reader / writer lock",
> > .lo_type = LOCKOPS_SLEEP,
> > @@ -179,6 +136,37 @@ syncobj_t rw_syncobj = {
> > };
> >
> > /*
> > + * rw_cas:
> > + *
> > + * Do an atomic compare-and-swap on the lock word.
> > + */
> > +static inline uintptr_t
> > +rw_cas(krwlock_t *rw, uintptr_t o, uintptr_t n)
> > +{
> > +
> > + return (uintptr_t)atomic_cas_ptr((volatile void *)&rw->rw_owner,
> > + (void *)o, (void *)n);
> > +}
> > +
> > +/*
> > + * rw_swap:
> > + *
> > + * Do an atomic swap of the lock word. This is used only when it's
> > + * known that the lock word is set up such that it can't be changed
> > + * behind us (assert this), so there's no point considering the result.
> > + */
> > +static inline void
> > +rw_swap(krwlock_t *rw, uintptr_t o, uintptr_t n)
> > +{
> > +
> > + n = (uintptr_t)atomic_swap_ptr((volatile void *)&rw->rw_owner,
> > + (void *)n);
> > +
> > + RW_ASSERT(rw, n == o);
> > + RW_ASSERT(rw, (o & RW_HAS_WAITERS) != 0);
> > +}
> > +
> > +/*
> > * rw_dump:
> > *
> > * Dump the contents of a rwlock structure.
> > @@ -214,16 +202,14 @@ rw_abort(const char *func, size_t line,
> > *
> > * Initialize a rwlock for use.
> > */
> > -void _rw_init(krwlock_t *, uintptr_t);
> > void
> > _rw_init(krwlock_t *rw, uintptr_t return_address)
> > {
> > - bool dodebug;
> >
> > - memset(rw, 0, sizeof(*rw));
> > -
> > - dodebug = LOCKDEBUG_ALLOC(rw, &rwlock_lockops, return_address);
> > - RW_SETDEBUG(rw, dodebug);
> > + if (LOCKDEBUG_ALLOC(rw, &rwlock_lockops, return_address))
> > + rw->rw_owner = 0;
> > + else
> > + rw->rw_owner = RW_NODEBUG;
> > }
> >
> > void
> > @@ -243,7 +229,7 @@ rw_destroy(krwlock_t *rw)
> > {
> >
> > RW_ASSERT(rw, (rw->rw_owner & ~RW_NODEBUG) == 0);
> > - LOCKDEBUG_FREE(RW_DEBUG_P(rw), rw);
> > + LOCKDEBUG_FREE((rw->rw_owner & RW_NODEBUG) == 0, rw);
> > }
> >
> > /*
> > @@ -327,7 +313,7 @@ rw_vector_enter(krwlock_t *rw, const krw
> > need_wait = RW_WRITE_LOCKED | RW_WRITE_WANTED;
> > queue = TS_READER_Q;
> > } else {
> > - RW_DASSERT(rw, op == RW_WRITER);
> > + RW_ASSERT(rw, op == RW_WRITER);
> > incr = curthread | RW_WRITE_LOCKED;
> > set_wait = RW_HAS_WAITERS | RW_WRITE_WANTED;
> > need_wait = RW_WRITE_LOCKED | RW_THREAD;
> > @@ -430,7 +416,7 @@ rw_vector_enter(krwlock_t *rw, const krw
> > (uintptr_t)__builtin_return_address(0)));
> > LOCKSTAT_EXIT(lsflag);
> >
> > - RW_DASSERT(rw, (op != RW_READER && RW_OWNER(rw) == curthread) ||
> > + RW_ASSERT(rw, (op != RW_READER && RW_OWNER(rw) == curthread) ||
> > (op == RW_READER && RW_COUNT(rw) != 0));
> > RW_LOCKED(rw, op);
> > }
> > @@ -448,7 +434,8 @@ rw_vector_exit(krwlock_t *rw)
> > int rcnt, wcnt;
> > lwp_t *l;
> >
> > - curthread = (uintptr_t)curlwp;
> > + l = curlwp;
> > + curthread = (uintptr_t)l;
> > RW_ASSERT(rw, curthread != 0);
> >
> > /*
> > @@ -491,8 +478,8 @@ rw_vector_exit(krwlock_t *rw)
> > */
> > ts = turnstile_lookup(rw);
> > owner = rw->rw_owner;
> > - RW_DASSERT(rw, ts != NULL);
> > - RW_DASSERT(rw, (owner & RW_HAS_WAITERS) != 0);
> > + RW_ASSERT(rw, ts != NULL);
> > + RW_ASSERT(rw, (owner & RW_HAS_WAITERS) != 0);
> >
> > wcnt = TS_WAITERS(ts, TS_WRITER_Q);
> > rcnt = TS_WAITERS(ts, TS_READER_Q);
> > @@ -509,31 +496,35 @@ rw_vector_exit(krwlock_t *rw)
> > * do the work of acquiring the lock in rw_vector_enter().
> > */
> > if (rcnt == 0 || decr == RW_READ_INCR) {
> > - RW_DASSERT(rw, wcnt != 0);
> > - RW_DASSERT(rw, (owner & RW_WRITE_WANTED) != 0);
> > + RW_ASSERT(rw, wcnt != 0);
> > + RW_ASSERT(rw, (owner & RW_WRITE_WANTED) != 0);
> >
> > if (rcnt != 0) {
> > /* Give the lock to the longest waiting writer. */
> > l = TS_FIRST(ts, TS_WRITER_Q);
> > - newown = (uintptr_t)l | RW_WRITE_LOCKED |
> > RW_HAS_WAITERS;
> > + newown = (uintptr_t)l | (owner & RW_NODEBUG);
> > + newown |= RW_WRITE_LOCKED | RW_HAS_WAITERS;
> > if (wcnt > 1)
> > newown |= RW_WRITE_WANTED;
> > rw_swap(rw, owner, newown);
> > turnstile_wakeup(ts, TS_WRITER_Q, 1, l);
> > } else {
> > /* Wake all writers and let them fight it out. */
> > - rw_swap(rw, owner, RW_WRITE_WANTED);
> > + newown = owner & RW_NODEBUG;
> > + newown |= RW_WRITE_WANTED;
> > + rw_swap(rw, owner, newown);
> > turnstile_wakeup(ts, TS_WRITER_Q, wcnt, NULL);
> > }
> > } else {
> > - RW_DASSERT(rw, rcnt != 0);
> > + RW_ASSERT(rw, rcnt != 0);
> >
> > /*
> > * Give the lock to all blocked readers. If there
> > * is a writer waiting, new readers that arrive
> > * after the release will be blocked out.
> > */
> > - newown = rcnt << RW_READ_COUNT_SHIFT;
> > + newown = owner & RW_NODEBUG;
> > + newown += rcnt << RW_READ_COUNT_SHIFT;
> > if (wcnt != 0)
> > newown |= RW_HAS_WAITERS | RW_WRITE_WANTED;
> >
> > @@ -552,8 +543,10 @@ int
> > rw_vector_tryenter(krwlock_t *rw, const krw_t op)
> > {
> > uintptr_t curthread, owner, incr, need_wait, next;
> > + lwp_t *l;
> >
> > - curthread = (uintptr_t)curlwp;
> > + l = curlwp;
> > + curthread = (uintptr_t)l;
> >
> > RW_ASSERT(rw, curthread != 0);
> >
> > @@ -561,7 +554,7 @@ rw_vector_tryenter(krwlock_t *rw, const
> > incr = RW_READ_INCR;
> > need_wait = RW_WRITE_LOCKED | RW_WRITE_WANTED;
> > } else {
> > - RW_DASSERT(rw, op == RW_WRITER);
> > + RW_ASSERT(rw, op == RW_WRITER);
> > incr = curthread | RW_WRITE_LOCKED;
> > need_wait = RW_WRITE_LOCKED | RW_THREAD;
> > }
> > @@ -572,24 +565,23 @@ rw_vector_tryenter(krwlock_t *rw, const
> > next = rw_cas(rw, owner, owner + incr);
> > if (__predict_true(next == owner)) {
> > /* Got it! */
> > - RW_MEMBAR_ENTER();
> > break;
> > }
> > }
> >
> > RW_WANTLOCK(rw, op);
> > RW_LOCKED(rw, op);
> > - RW_DASSERT(rw, (op != RW_READER && RW_OWNER(rw) == curthread) ||
> > + RW_ASSERT(rw, (op != RW_READER && RW_OWNER(rw) == curthread) ||
> > (op == RW_READER && RW_COUNT(rw) != 0));
> >
> > + RW_MEMBAR_ENTER();
> > return 1;
> > }
> >
> > /*
> > * rw_downgrade:
> > *
> > - * Downgrade a write lock to a read lock. Optimise memory accesses for
> > - * the uncontended case.
> > + * Downgrade a write lock to a read lock.
> > */
> > void
> > rw_downgrade(krwlock_t *rw)
> > @@ -597,55 +589,64 @@ rw_downgrade(krwlock_t *rw)
> > uintptr_t owner, curthread, newown, next;
> > turnstile_t *ts;
> > int rcnt, wcnt;
> > + lwp_t *l;
> >
> > - curthread = (uintptr_t)curlwp;
> > + l = curlwp;
> > + curthread = (uintptr_t)l;
> > RW_ASSERT(rw, curthread != 0);
> > - RW_DASSERT(rw, (rw->rw_owner & RW_WRITE_LOCKED) != 0);
> > + RW_ASSERT(rw, (rw->rw_owner & RW_WRITE_LOCKED) != 0);
> > RW_ASSERT(rw, RW_OWNER(rw) == curthread);
> > RW_UNLOCKED(rw, RW_WRITER);
> > #if !defined(DIAGNOSTIC)
> > __USE(curthread);
> > #endif
> >
> > - /*
> > - * If there are no waiters, so we can do this the easy way.
> > - * Try swapping us down to one read hold. If it fails, the
> > - * lock condition has changed and we most likely now have
> > - * waiters.
> > - */
> > RW_MEMBAR_PRODUCER();
> > - owner = curthread | RW_WRITE_LOCKED;
> > - next = rw_cas(rw, owner, RW_READ_INCR);
> > - if (__predict_true(next == owner)) {
> > - RW_LOCKED(rw, RW_READER);
> > - RW_DASSERT(rw, (rw->rw_owner & RW_WRITE_LOCKED) == 0);
> > - RW_DASSERT(rw, RW_COUNT(rw) != 0);
> > - return;
> > - }
> >
> > - /*
> > - * Grab the turnstile chain lock. This gets the interlock
> > - * on the sleep queue. Once we have that, we can adjust the
> > - * waiter bits.
> > - */
> > - for (;;) {
> > - owner = next;
> > + for (owner = rw->rw_owner;; owner = next) {
> > + /*
> > + * If there are no waiters we can do this the easy way. Try
> > + * swapping us down to one read hold. If it fails, the lock
> > + * condition has changed and we most likely now have
> > + * waiters.
> > + */
> > + if ((owner & RW_HAS_WAITERS) == 0) {
> > + newown = (owner & RW_NODEBUG);
> > + next = rw_cas(rw, owner, newown + RW_READ_INCR);
> > + if (__predict_true(next == owner)) {
> > + RW_LOCKED(rw, RW_READER);
> > + RW_ASSERT(rw,
> > + (rw->rw_owner & RW_WRITE_LOCKED) == 0);
> > + RW_ASSERT(rw, RW_COUNT(rw) != 0);
> > + return;
> > + }
> > + continue;
> > + }
> > +
> > + /*
> > + * Grab the turnstile chain lock. This gets the interlock
> > + * on the sleep queue. Once we have that, we can adjust the
> > + * waiter bits.
> > + */
> > ts = turnstile_lookup(rw);
> > - RW_DASSERT(rw, ts != NULL);
> > + RW_ASSERT(rw, ts != NULL);
> >
> > rcnt = TS_WAITERS(ts, TS_READER_Q);
> > wcnt = TS_WAITERS(ts, TS_WRITER_Q);
> >
> > - /*
> > - * If there are no readers, just preserve the waiters
> > - * bits, swap us down to one read hold and return.
> > - */
> > if (rcnt == 0) {
> > - RW_DASSERT(rw, wcnt != 0);
> > - RW_DASSERT(rw, (rw->rw_owner & RW_WRITE_WANTED) != 0);
> > - RW_DASSERT(rw, (rw->rw_owner & RW_HAS_WAITERS) != 0);
> > -
> > - newown = RW_READ_INCR | RW_HAS_WAITERS |
> > RW_WRITE_WANTED;
> > + /*
> > + * If there are no readers, just preserve the
> > + * waiters bits, swap us down to one read hold and
> > + * return.
> > + */
> > + RW_ASSERT(rw, wcnt != 0);
> > + RW_ASSERT(rw, (rw->rw_owner & RW_WRITE_WANTED) != 0);
> > + RW_ASSERT(rw, (rw->rw_owner & RW_HAS_WAITERS) != 0);
> > +
> > + newown = owner & RW_NODEBUG;
> > + newown = RW_READ_INCR | RW_HAS_WAITERS |
> > + RW_WRITE_WANTED;
> > next = rw_cas(rw, owner, newown);
> > turnstile_exit(rw);
> > if (__predict_true(next == owner))
> > @@ -653,11 +654,12 @@ rw_downgrade(krwlock_t *rw)
> > } else {
> > /*
> > * Give the lock to all blocked readers. We may
> > - * retain one read hold if downgrading. If there
> > - * is a writer waiting, new readers will be blocked
> > + * retain one read hold if downgrading. If there is
> > + * a writer waiting, new readers will be blocked
> > * out.
> > */
> > - newown = (rcnt << RW_READ_COUNT_SHIFT) + RW_READ_INCR;
> > + newown = owner & RW_NODEBUG;
> > + newown += (rcnt << RW_READ_COUNT_SHIFT) + RW_READ_INCR;
> > if (wcnt != 0)
> > newown |= RW_HAS_WAITERS | RW_WRITE_WANTED;
> >
> > @@ -673,22 +675,24 @@ rw_downgrade(krwlock_t *rw)
> >
> > RW_WANTLOCK(rw, RW_READER);
> > RW_LOCKED(rw, RW_READER);
> > - RW_DASSERT(rw, (rw->rw_owner & RW_WRITE_LOCKED) == 0);
> > - RW_DASSERT(rw, RW_COUNT(rw) != 0);
> > + RW_ASSERT(rw, (rw->rw_owner & RW_WRITE_LOCKED) == 0);
> > + RW_ASSERT(rw, RW_COUNT(rw) != 0);
> > }
> >
> > /*
> > * rw_tryupgrade:
> > *
> > * Try to upgrade a read lock to a write lock. We must be the only
> > - * reader. Optimise memory accesses for the uncontended case.
> > + * reader.
> > */
> > int
> > rw_tryupgrade(krwlock_t *rw)
> > {
> > uintptr_t owner, curthread, newown, next;
> > + struct lwp *l;
> >
> > - curthread = (uintptr_t)curlwp;
> > + l = curlwp;
> > + curthread = (uintptr_t)l;
> > RW_ASSERT(rw, curthread != 0);
> > RW_ASSERT(rw, rw_read_held(rw));
> >
> > @@ -709,8 +713,8 @@ rw_tryupgrade(krwlock_t *rw)
> > RW_UNLOCKED(rw, RW_READER);
> > RW_WANTLOCK(rw, RW_WRITER);
> > RW_LOCKED(rw, RW_WRITER);
> > - RW_DASSERT(rw, rw->rw_owner & RW_WRITE_LOCKED);
> > - RW_DASSERT(rw, RW_OWNER(rw) == curthread);
> > + RW_ASSERT(rw, rw->rw_owner & RW_WRITE_LOCKED);
> > + RW_ASSERT(rw, RW_OWNER(rw) == curthread);
> >
> > return 1;
> > }
> >
> > Index: src/sys/sys/rwlock.h
> > diff -u src/sys/sys/rwlock.h:1.12 src/sys/sys/rwlock.h:1.13
> > --- src/sys/sys/rwlock.h:1.12 Wed Jan 1 21:34:39 2020
> > +++ src/sys/sys/rwlock.h Sun Jan 19 18:34:24 2020
> > @@ -1,7 +1,7 @@
> > -/* $NetBSD: rwlock.h,v 1.12 2020/01/01 21:34:39 ad Exp $ */
> > +/* $NetBSD: rwlock.h,v 1.13 2020/01/19 18:34:24 ad Exp $ */
> >
> > /*-
> > - * Copyright (c) 2002, 2006, 2007, 2008, 2019 The NetBSD Foundation, Inc.
> > + * Copyright (c) 2002, 2006, 2007, 2008, 2019, 2020 The NetBSD Foundation,
> > Inc.
> > * All rights reserved.
> > *
> > * This code is derived from software contributed to The NetBSD Foundation
> > @@ -45,10 +45,6 @@
> > * rw_tryenter()
> > */
> >
> > -#if defined(_KERNEL_OPT)
> > -#include "opt_lockdebug.h"
> > -#endif
> > -
> > #if !defined(_KERNEL)
> > #include <sys/types.h>
> > #include <sys/inttypes.h>
> > @@ -75,13 +71,9 @@ typedef struct krwlock krwlock_t;
> > #define RW_HAS_WAITERS 0x01UL /* lock has waiters */
> > #define RW_WRITE_WANTED 0x02UL /* >= 1 waiter is a writer */
> > #define RW_WRITE_LOCKED 0x04UL /* lock is currently write
> > locked */
> > -#if defined(LOCKDEBUG)
> > -#define RW_NODEBUG 0x08UL /* LOCKDEBUG disabled */
> > -#else
> > -#define RW_NODEBUG 0x00UL /* do nothing */
> > -#endif /* LOCKDEBUG */
> > +#define RW_NODEBUG 0x10UL /* LOCKDEBUG disabled */
> >
> > -#define RW_READ_COUNT_SHIFT 4
> > +#define RW_READ_COUNT_SHIFT 5
> > #define RW_READ_INCR (1UL << RW_READ_COUNT_SHIFT)
> > #define RW_THREAD ((uintptr_t)-RW_READ_INCR)
> > #define RW_OWNER(rw) ((rw)->rw_owner & RW_THREAD)
> > @@ -91,6 +83,7 @@ typedef struct krwlock krwlock_t;
> > void rw_vector_enter(krwlock_t *, const krw_t);
> > void rw_vector_exit(krwlock_t *);
> > int rw_vector_tryenter(krwlock_t *, const krw_t);
> > +void _rw_init(krwlock_t *, uintptr_t);
> > #endif /* __RWLOCK_PRIVATE */
> >
> > struct krwlock {
> >
>
> --
> Ryo ONODERA // r...@tetera.org
> PGP fingerprint = 82A2 DC91 76E0 A10A 8ABB FD1B F404 27FA C7D1 15F3
