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: stable/11/sys/compat/linuxkpi/common/include/linux/rwsem.h 331756 2018-03-30 02:04:46Z emaste $ 30 */ 31#ifndef _LINUX_RWSEM_H_ 32#define _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 40struct 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 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) \ 67struct rw_semaphore name; \ 68static void name##_rwsem_init(void *arg) \ 69{ \ 70 linux_init_rwsem(&name, rwsem_name(#name)); \ 71} \ 72SYSINIT(name, SI_SUB_LOCK, SI_ORDER_SECOND, name##_rwsem_init, NULL) 73 74static inline void 75linux_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 82extern int linux_down_write_killable(struct rw_semaphore *); 83 84#endif /* _LINUX_RWSEM_H_ */ 85