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 #ifndef _LINUXKPI_LINUX_RWSEM_H_ 30 #define _LINUXKPI_LINUX_RWSEM_H_ 31 32 #include <sys/param.h> 33 #include <sys/lock.h> 34 #include <sys/sx.h> 35 #include <sys/libkern.h> 36 #include <sys/kernel.h> 37 38 struct rw_semaphore { 39 struct sx sx; 40 }; 41 42 #define down_write(_rw) sx_xlock(&(_rw)->sx) 43 #define up_write(_rw) sx_xunlock(&(_rw)->sx) 44 #define down_read(_rw) sx_slock(&(_rw)->sx) 45 #define up_read(_rw) sx_sunlock(&(_rw)->sx) 46 #define down_read_trylock(_rw) !!sx_try_slock(&(_rw)->sx) 47 #define down_read_killable(_rw) linux_down_read_killable(_rw) 48 #define down_write_trylock(_rw) !!sx_try_xlock(&(_rw)->sx) 49 #define down_write_killable(_rw) linux_down_write_killable(_rw) 50 #define downgrade_write(_rw) sx_downgrade(&(_rw)->sx) 51 #define down_read_nested(_rw, _sc) down_read(_rw) 52 #define init_rwsem(_rw) linux_init_rwsem(_rw, rwsem_name("lnxrwsem")) 53 #define down_write_nest_lock(sem, _rw) down_write(_rw) 54 55 #ifdef WITNESS_ALL 56 /* NOTE: the maximum WITNESS name is 64 chars */ 57 #define __rwsem_name(name, file, line) \ 58 (((const char *){file ":" #line "-" name}) + \ 59 (sizeof(file) > 16 ? sizeof(file) - 16 : 0)) 60 #else 61 #define __rwsem_name(name, file, line) name 62 #endif 63 #define _rwsem_name(...) __rwsem_name(__VA_ARGS__) 64 #define rwsem_name(name) _rwsem_name(name, __FILE__, __LINE__) 65 66 #define DECLARE_RWSEM(name) \ 67 struct rw_semaphore name; \ 68 static void name##_rwsem_init(void *arg) \ 69 { \ 70 linux_init_rwsem(&name, rwsem_name(#name)); \ 71 } \ 72 SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_rwsem_init, NULL) 73 74 static inline void 75 linux_init_rwsem(struct rw_semaphore *rw, const char *name) 76 { 77 78 memset(rw, 0, sizeof(*rw)); 79 sx_init_flags(&rw->sx, name, SX_NOWITNESS); 80 } 81 82 extern int linux_down_read_killable(struct rw_semaphore *); 83 extern int linux_down_write_killable(struct rw_semaphore *); 84 85 #endif /* _LINUXKPI_LINUX_RWSEM_H_ */ 86