1 /*- 2 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #ifndef _OPENSOLARIS_SYS_RWLOCK_H_ 28 #define _OPENSOLARIS_SYS_RWLOCK_H_ 29 30 #include <sys/param.h> 31 #include <sys/proc.h> 32 #include <sys/lock.h> 33 #include <sys/sx.h> 34 35 #ifdef _KERNEL 36 37 typedef enum { 38 RW_DEFAULT = 4 /* kernel default rwlock */ 39 } krw_type_t; 40 41 typedef enum { 42 RW_WRITER, 43 RW_READER 44 } krw_t; 45 46 typedef struct sx krwlock_t; 47 48 #ifndef OPENSOLARIS_WITNESS 49 #define RW_FLAGS (SX_DUPOK | SX_NOWITNESS) 50 #else 51 #define RW_FLAGS (SX_DUPOK) 52 #endif 53 54 #define RW_READ_HELD(x) (rw_read_held((x))) 55 #define RW_WRITE_HELD(x) (rw_write_held((x))) 56 #define RW_LOCK_HELD(x) (rw_lock_held((x))) 57 #define RW_ISWRITER(x) (rw_iswriter(x)) 58 59 #define rw_init(lock, desc, type, arg) do { \ 60 const char *_name; \ 61 ASSERT((type) == 0 || (type) == RW_DEFAULT); \ 62 KASSERT(((lock)->lock_object.lo_flags & LO_ALLMASK) != \ 63 LO_EXPECTED, ("lock %s already initialized", #lock)); \ 64 bzero((lock), sizeof(struct sx)); \ 65 for (_name = #lock; *_name != '\0'; _name++) { \ 66 if (*_name >= 'a' && *_name <= 'z') \ 67 break; \ 68 } \ 69 if (*_name == '\0') \ 70 _name = #lock; \ 71 sx_init_flags((lock), _name, RW_FLAGS); \ 72 } while (0) 73 #define rw_destroy(lock) sx_destroy(lock) 74 #define rw_enter(lock, how) do { \ 75 if ((how) == RW_READER) \ 76 sx_slock(lock); \ 77 else /* if ((how) == RW_WRITER) */ \ 78 sx_xlock(lock); \ 79 } while (0) 80 #define rw_tryenter(lock, how) ((how) == RW_READER ? sx_try_slock(lock) : sx_try_xlock(lock)) 81 #define rw_exit(lock) sx_unlock(lock) 82 #define rw_downgrade(lock) sx_downgrade(lock) 83 #define rw_tryupgrade(lock) sx_try_upgrade(lock) 84 #define rw_read_held(lock) ((lock)->sx_lock != SX_LOCK_UNLOCKED && ((lock)->sx_lock & SX_LOCK_SHARED)) 85 #define rw_write_held(lock) sx_xlocked(lock) 86 #define rw_lock_held(lock) (rw_read_held(lock) || rw_write_held(lock)) 87 #define rw_iswriter(lock) sx_xlocked(lock) 88 #define rw_owner(lock) sx_xholder(lock) 89 90 #endif /* defined(_KERNEL) */ 91 92 #endif /* _OPENSOLARIS_SYS_RWLOCK_H_ */ 93