1 /*- 2 * Copyright (c) 2010 Isilon Systems, Inc. 3 * Copyright (c) 2010 iX Systems, Inc. 4 * Copyright (c) 2010 Panasas, Inc. 5 * Copyright (c) 2013-2017 Mellanox Technologies, Ltd. 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice unmodified, this list of conditions, and the following 13 * disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 #ifndef _LINUXKPI_LINUX_RWSEM_H_ 32 #define _LINUXKPI_LINUX_RWSEM_H_ 33 34 #include <sys/param.h> 35 #include <sys/lock.h> 36 #include <sys/sx.h> 37 #include <sys/libkern.h> 38 #include <sys/kernel.h> 39 40 struct rw_semaphore { 41 struct sx sx; 42 }; 43 44 #define down_write(_rw) sx_xlock(&(_rw)->sx) 45 #define up_write(_rw) sx_xunlock(&(_rw)->sx) 46 #define down_read(_rw) sx_slock(&(_rw)->sx) 47 #define up_read(_rw) sx_sunlock(&(_rw)->sx) 48 #define down_read_trylock(_rw) !!sx_try_slock(&(_rw)->sx) 49 #define down_write_trylock(_rw) !!sx_try_xlock(&(_rw)->sx) 50 #define down_write_killable(_rw) linux_down_write_killable(_rw) 51 #define downgrade_write(_rw) sx_downgrade(&(_rw)->sx) 52 #define down_read_nested(_rw, _sc) down_read(_rw) 53 #define init_rwsem(_rw) linux_init_rwsem(_rw, rwsem_name("lnxrwsem")) 54 #define down_write_nest_lock(sem, _rw) down_write(_rw) 55 56 #ifdef WITNESS_ALL 57 /* NOTE: the maximum WITNESS name is 64 chars */ 58 #define __rwsem_name(name, file, line) \ 59 (((const char *){file ":" #line "-" name}) + \ 60 (sizeof(file) > 16 ? sizeof(file) - 16 : 0)) 61 #else 62 #define __rwsem_name(name, file, line) name 63 #endif 64 #define _rwsem_name(...) __rwsem_name(__VA_ARGS__) 65 #define rwsem_name(name) _rwsem_name(name, __FILE__, __LINE__) 66 67 #define DECLARE_RWSEM(name) \ 68 struct rw_semaphore name; \ 69 static void name##_rwsem_init(void *arg) \ 70 { \ 71 linux_init_rwsem(&name, rwsem_name(#name)); \ 72 } \ 73 SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_rwsem_init, NULL) 74 75 static inline void 76 linux_init_rwsem(struct rw_semaphore *rw, const char *name) 77 { 78 79 memset(rw, 0, sizeof(*rw)); 80 sx_init_flags(&rw->sx, name, SX_NOWITNESS); 81 } 82 83 extern int linux_down_write_killable(struct rw_semaphore *); 84 85 #endif /* _LINUXKPI_LINUX_RWSEM_H_ */ 86