1/* 2 * sync abstraction 3 * Copyright 2015-2016 Collabora Ltd. 4 * 5 * Based on the implementation from the Android Open Source Project, 6 * 7 * Copyright 2012 Google, Inc 8 * 9 * Permission is hereby granted, free of charge, to any person obtaining a 10 * copy of this software and associated documentation files (the "Software"), 11 * to deal in the Software without restriction, including without limitation 12 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 13 * and/or sell copies of the Software, and to permit persons to whom the 14 * Software is furnished to do so, subject to the following conditions: 15 * 16 * The above copyright notice and this permission notice shall be included in 17 * all copies or substantial portions of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR 23 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, 24 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 25 * OTHER DEALINGS IN THE SOFTWARE. 26 */ 27 28#ifndef _LIBSYNC_H 29#define _LIBSYNC_H 30 31#include <assert.h> 32#include <errno.h> 33#include <stdbool.h> 34#include <stdint.h> 35#include <string.h> 36#include <sys/ioctl.h> 37#include <sys/poll.h> 38#include <unistd.h> 39#include <time.h> 40 41#if defined(__cplusplus) 42extern "C" { 43#endif 44 45#ifdef ANDROID 46/* On Android, rely on the system's libsync instead of rolling our own 47 * sync_wait() and sync_merge(). This gives us compatibility with pre-4.7 48 * Android kernels. 49 */ 50#include <android/sync.h> 51 52/** 53 * Check if the fd represents a valid fence-fd. 54 * 55 * The android variant of this debug helper is implemented on top of the 56 * system's libsync for compatibility with pre-4.7 android kernels. 57 */ 58static inline bool 59sync_valid_fd(int fd) 60{ 61 /* sync_file_info() only available in SDK 26. */ 62#if ANDROID_API_LEVEL >= 26 63 struct sync_file_info *info = sync_file_info(fd); 64 if (!info) 65 return false; 66 sync_file_info_free(info); 67#endif 68 return true; 69} 70#else 71 72#ifndef SYNC_IOC_MERGE 73/* duplicated from linux/sync_file.h to avoid build-time dependency 74 * on new (v4.7) kernel headers. Once distro's are mostly using 75 * something newer than v4.7 drop this and #include <linux/sync_file.h> 76 * instead. 77 */ 78struct sync_merge_data { 79 char name[32]; 80 int32_t fd2; 81 int32_t fence; 82 uint32_t flags; 83 uint32_t pad; 84}; 85 86struct sync_file_info { 87 char name[32]; 88 int32_t status; 89 uint32_t flags; 90 uint32_t num_fences; 91 uint32_t pad; 92 93 uint64_t sync_fence_info; 94}; 95 96#define SYNC_IOC_MAGIC '>' 97#define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data) 98#define SYNC_IOC_FILE_INFO _IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info) 99#endif 100 101 102static inline int sync_wait(int fd, int timeout) 103{ 104 struct pollfd fds = {0}; 105 int ret; 106 struct timespec poll_start, poll_end; 107 108 fds.fd = fd; 109 fds.events = POLLIN; 110 111 do { 112 clock_gettime(CLOCK_MONOTONIC, &poll_start); 113 ret = poll(&fds, 1, timeout); 114 clock_gettime(CLOCK_MONOTONIC, &poll_end); 115 if (ret > 0) { 116 if (fds.revents & (POLLERR | POLLNVAL)) { 117 errno = EINVAL; 118 return -1; 119 } 120 return 0; 121 } else if (ret == 0) { 122 errno = ETIME; 123 return -1; 124 } 125 timeout -= (poll_end.tv_sec - poll_start.tv_sec) * 1000 + 126 (poll_end.tv_nsec - poll_end.tv_nsec) / 1000000; 127 } while (ret == -1 && (errno == EINTR || errno == EAGAIN)); 128 129 return ret; 130} 131 132static inline int sync_merge(const char *name, int fd1, int fd2) 133{ 134 struct sync_merge_data data = {{0}}; 135 int ret; 136 137 data.fd2 = fd2; 138 strncpy(data.name, name, sizeof(data.name)); 139 140 do { 141 ret = ioctl(fd1, SYNC_IOC_MERGE, &data); 142 } while (ret == -1 && (errno == EINTR || errno == EAGAIN)); 143 144 if (ret < 0) 145 return ret; 146 147 return data.fence; 148} 149 150/** 151 * Check if the fd represents a valid fence-fd. 152 */ 153static inline bool 154sync_valid_fd(int fd) 155{ 156 struct sync_file_info info = {{0}}; 157 return ioctl(fd, SYNC_IOC_FILE_INFO, &info) >= 0; 158} 159 160#endif /* !ANDROID */ 161 162/* accumulate fd2 into fd1. If *fd1 is not a valid fd then dup fd2, 163 * otherwise sync_merge() and close the old *fd1. This can be used 164 * to implement the pattern: 165 * 166 * init() 167 * { 168 * batch.fence_fd = -1; 169 * } 170 * 171 * // does *NOT* take ownership of fd 172 * server_sync(int fd) 173 * { 174 * if (sync_accumulate("foo", &batch.fence_fd, fd)) { 175 * ... error ... 176 * } 177 * } 178 */ 179static inline int sync_accumulate(const char *name, int *fd1, int fd2) 180{ 181 int ret; 182 183 assert(fd2 >= 0); 184 185 if (*fd1 < 0) { 186 *fd1 = dup(fd2); 187 return 0; 188 } 189 190 ret = sync_merge(name, *fd1, fd2); 191 if (ret < 0) { 192 /* leave *fd1 as it is */ 193 return ret; 194 } 195 196 close(*fd1); 197 *fd1 = ret; 198 199 return 0; 200} 201 202/* Helper macro to complain if fd is non-negative and not a valid fence fd. 203 * Sprinkle this around to help catch fd lifetime issues. 204 */ 205#ifdef DEBUG 206# include "util/log.h" 207# define validate_fence_fd(fd) do { \ 208 if (((fd) >= 0) && !sync_valid_fd(fd)) \ 209 mesa_loge("%s:%d: invalid fence fd: %d", __func__, __LINE__, (fd)); \ 210 } while (0) 211#else 212# define validate_fence_fd(fd) do {} while (0) 213#endif 214 215#if defined(__cplusplus) 216} 217#endif 218 219#endif 220