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[v6,05/15] dma-buf/sync_file: Add SET_DEADLINE ioctl

Message ID 20230224200155.2510320-6-robdclark@gmail.com
State New
Headers show
Series dma-fence: Deadline awareness | expand

Commit Message

Rob Clark Feb. 24, 2023, 8:01 p.m. UTC 
From: Rob Clark <robdclark@chromium.org>

The initial purpose is for igt tests, but this would also be useful for
compositors that wait until close to vblank deadline to make decisions
about which frame to show.

The igt tests can be found at:

https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline

v2: Clarify the timebase, add link to igt tests
v3: Use u64 value in ns to express deadline.

Signed-off-by: Rob Clark <robdclark@chromium.org>
---
 drivers/dma-buf/sync_file.c    | 19 +++++++++++++++++++
 include/uapi/linux/sync_file.h | 22 ++++++++++++++++++++++
 2 files changed, 41 insertions(+)
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Patch

diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index af57799c86ce..418021cfb87c 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -350,6 +350,22 @@  static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
 	return ret;
 }
 
+static int sync_file_ioctl_set_deadline(struct sync_file *sync_file,
+					unsigned long arg)
+{
+	struct sync_set_deadline ts;
+
+	if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
+		return -EFAULT;
+
+	if (ts.pad)
+		return -EINVAL;
+
+	dma_fence_set_deadline(sync_file->fence, ns_to_ktime(ts.deadline_ns));
+
+	return 0;
+}
+
 static long sync_file_ioctl(struct file *file, unsigned int cmd,
 			    unsigned long arg)
 {
@@ -362,6 +378,9 @@  static long sync_file_ioctl(struct file *file, unsigned int cmd,
 	case SYNC_IOC_FILE_INFO:
 		return sync_file_ioctl_fence_info(sync_file, arg);
 
+	case SYNC_IOC_SET_DEADLINE:
+		return sync_file_ioctl_set_deadline(sync_file, arg);
+
 	default:
 		return -ENOTTY;
 	}
diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
index ee2dcfb3d660..49325cf6749b 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -67,6 +67,21 @@  struct sync_file_info {
 	__u64	sync_fence_info;
 };
 
+/**
+ * struct sync_set_deadline - set a deadline hint on a fence
+ * @deadline_ns: absolute time of the deadline
+ * @pad:	must be zero
+ *
+ * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank)
+ */
+struct sync_set_deadline {
+	__u64	deadline_ns;
+	/* Not strictly needed for alignment but gives some possibility
+	 * for future extension:
+	 */
+	__u64	pad;
+};
+
 #define SYNC_IOC_MAGIC		'>'
 
 /**
@@ -95,4 +110,11 @@  struct sync_file_info {
  */
 #define SYNC_IOC_FILE_INFO	_IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
 
+/**
+ * DOC: SYNC_IOC_SET_DEADLINE - set a deadline on a fence
+ *
+ * Allows userspace to set a deadline on a fence, see dma_fence_set_deadline()
+ */
+#define SYNC_IOC_SET_DEADLINE	_IOW(SYNC_IOC_MAGIC, 5, struct sync_set_deadline)
+
 #endif /* _UAPI_LINUX_SYNC_H */