From: Rob Clark robclark@freedesktop.org
Rather than cut/pasting these couple ioctl wrappers everywhere, just stuff them as static-inline into a header.
This is probably mostly used from mesa, but some drivers, test apps, etc may also want to use it from libdrm.
v2: handle EINTR, add sync_accumulate() based on #dri-devel discussion, etc
Signed-off-by: Rob Clark robclark@freedesktop.org --- Makefile.sources | 1 + libsync.h | 145 +++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 146 insertions(+) create mode 100644 libsync.h
diff --git a/Makefile.sources b/Makefile.sources index a57036a..10aa1d0 100644 --- a/Makefile.sources +++ b/Makefile.sources @@ -13,6 +13,7 @@ LIBDRM_FILES := \ util_math.h
LIBDRM_H_FILES := \ + libsync.h \ xf86drm.h \ xf86drmMode.h
diff --git a/libsync.h b/libsync.h new file mode 100644 index 0000000..2f9aafb --- /dev/null +++ b/libsync.h @@ -0,0 +1,145 @@ +/* + * sync abstraction + * Copyright 2015-2016 Collabora Ltd. + * + * Based on the implementation from the Android Open Source Project, + * + * Copyright 2012 Google, Inc + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +#ifndef _LIBSYNC_H +#define _LIBSYNC_H + +#include <assert.h> +#include <errno.h> +#include <stdint.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/poll.h> +#include <unistd.h> + +#if defined(__cplusplus) +extern "C" { +#endif + +/* duplicated from linux/sync_file.h to avoid build-time dependency + * on new headers + */ +struct sync_merge_data { + char name[32]; + int32_t fd2; + int32_t fence; + uint32_t flags; + uint32_t pad; +}; +#define SYNC_IOC_MAGIC '>' +#define SYNC_IOC_MERGE _IOWR(SYNC_IOC_MAGIC, 3, struct sync_merge_data) + + + +static inline int sync_wait(int fd, int timeout) +{ + struct pollfd fds = {0}; + int ret; + + fds.fd = fd; + fds.events = POLLIN; + + do { + ret = poll(&fds, 1, timeout); + if (ret > 0) { + if (fds.revents & (POLLERR | POLLNVAL)) { + errno = EINVAL; + return -1; + } + return 0; + } else if (ret == 0) { + errno = ETIME; + return -1; + } + } while (ret == -1 && (errno == EINTR || errno == EAGAIN)); + + return ret; +} + +static inline int sync_merge(const char *name, int fd1, int fd2) +{ + struct sync_merge_data data = {0}; + int ret; + + data.fd2 = fd2; + strncpy(data.name, name, sizeof(data.name)); + + do { + ret = ioctl(fd1, SYNC_IOC_MERGE, &data); + } while (ret == -1 && (errno == EINTR || errno == EAGAIN)); + + if (ret < 0) + return ret; + + return data.fence; +} + +/* accumulate fd2 into fd1. If *fd1 is not a valid fd then dup fd2, + * otherwise sync_merge() and close the old *fd1. This can be used + * to implement the pattern: + * + * init() + * { + * batch.fence_fd = 1; + * } + * + * // does *NOT* take ownership of fd + * server_sync(int fd) + * { + * if (sync_accumulate("foo", &batch.fence_fd, fd)) { + * ... error ... + * } + * } + */ +static inline int sync_accumulate(const char *name, int *fd1, int fd2) +{ + int ret; + + assert(fd2 >= 0); + + if (*fd1 < 0) { + *fd1 = dup(fd2); + return 0; + } + + ret = sync_merge(name, *fd1, fd2); + if (ret < 0) { + /* leave *fd1 as it is */ + return ret; + } + + close(*fd1); + *fd1 = ret; + + return 0; +} + +#if defined(__cplusplus) +} +#endif + +#endif