Module: Mesa
Branch: master
Commit: e8c89a9bcbaf85bd8772991151cbef7c0a2ddd76
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=e8c89a9bcbaf85bd8772991151cbef7c0a2ddd76
Author: Eric Anholt <e...@anholt.net>
Date: Tue Sep 22 12:59:24 2020 -0700
util: Import a copy of drm's libsync.h
libsync.h is one of the common dependencies on libdrm from drivers that
otherwise don't want libdrm. Given that it's header-only code, just
import it to Mesa instead of forcing library dependencies on our users.
Copied from libdrm commit a84caff71be9 (" intel: Add PCI ID support to RKL
platform")
Reviewed-by: Kristian H. Kristensen <hoegsb...@google.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6821>
---
src/util/libsync.h | 148 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 148 insertions(+)
diff --git a/src/util/libsync.h b/src/util/libsync.h
new file mode 100644
index 00000000000..f1a2f96d36b
--- /dev/null
+++ b/src/util/libsync.h
@@ -0,0 +1,148 @@
+/*
+ * 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
+
+#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 = 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
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