IABSD.fr/xenocara/lib/libdrm/libsync.h

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• Author : jsg
  Date : 2024-10-17 10:00:00
  Hash : 888647a0
  Message : Merge libdrm 2.4.123

• lib/libdrm/libsync.h

• /*
   *  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 <poll.h>
  #include <unistd.h>
  
  #if defined(__cplusplus)
  extern "C" {
  #endif
  
  #ifndef SYNC_IOC_MERGE
  /* duplicated from linux/sync_file.h to avoid build-time dependency
   * on new (v4.7) kernel headers.  Once distro's are mostly using
   * something newer than v4.7 drop this and #include <linux/sync_file.h>
   * instead.
   */
  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)
  #endif
  
  
  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 = ETIMEDOUT;
  			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