diff options
Diffstat (limited to 'usr/src/uts/common/os/rwstlock.c')
| -rw-r--r-- | usr/src/uts/common/os/rwstlock.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/usr/src/uts/common/os/rwstlock.c b/usr/src/uts/common/os/rwstlock.c index 7308447fab..85f1ef6e05 100644 --- a/usr/src/uts/common/os/rwstlock.c +++ b/usr/src/uts/common/os/rwstlock.c @@ -24,7 +24,9 @@ * Use is subject to license terms. */ -#pragma ident "%Z%%M% %I% %E% SMI" +/* + * Copyright (c) 2013, Joyent, Inc. All rights reserved. + */ #include <sys/rwstlock.h> #include <sys/errno.h> @@ -38,7 +40,9 @@ * other than the one that acquired the lock. * * There is no priority inheritance mechanism for these locks. - * Writers have priority over readers, so reader starvation is possible. + * For RW_READER, writers have priority over readers, so reader starvation + * is possible; as with rwlocks, this behavior may be overridden by + * specifying RW_READER_STARVEWRITER. */ /* @@ -61,8 +65,9 @@ rwst_enter_common(rwstlock_t *l, krw_t rw, int flags) intptr_t readers; mutex_enter(&l->rwst_lock); - if (rw == RW_READER) { - while (RWST_WRITE_HELD(l) || RWST_WRITE_WANTED(l)) { + if (rw == RW_READER || rw == RW_READER_STARVEWRITER) { + while (RWST_WRITE_HELD(l) || + (rw != RW_READER_STARVEWRITER && RWST_WRITE_WANTED(l))) { if (flags & RWST_TRYENTER) { mutex_exit(&l->rwst_lock); @@ -164,7 +169,7 @@ rwst_tryenter(rwstlock_t *l, krw_t rw) int rwst_lock_held(rwstlock_t *l, krw_t rw) { - if (rw == RW_READER) + if (rw != RW_WRITER) return (RWST_READ_HELD(l)); ASSERT(rw == RW_WRITER); return (RWST_WRITE_OWNER(l)); |