From: Dave Airlie <airlied@xxxxxxxxxx>
This object can be used to implement the Vulkan semaphores.
The object behaviour differs from fence, in that you can
replace the underlying fence, and you cannot merge semaphores.
Signed-off-by: Dave Airlie <airlied at redhat.com>
---
drivers/dma-buf/sync_file.c | 36 +++++++++++++++++++++++++++++++++++-
include/linux/sync_file.h | 2 ++
include/uapi/linux/sync_file.h | 14 ++++++++++++++
3 files changed, 51 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index d84de67..a5b17c0 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -44,7 +44,7 @@ int sync_file_validate_type_flags(uint32_t type, uint32_t flags)
{
if (flags)
return -EINVAL;
- if (type != SYNC_FILE_TYPE_FENCE)
+ if (type != SYNC_FILE_TYPE_FENCE && type != SYNC_FILE_TYPE_SEMAPHORE)
return -EINVAL;
return 0;
}
@@ -202,6 +202,38 @@ sync_file_get_fence_locked(struct sync_file *sync_file)
sync_file_held(sync_file));
}
+/**
+ * sync_file_replace_fence - replace the fence related to the sync_file
+ * @sync_file: sync file to replace fence in
+ * @fence: fence to replace with (or NULL for no fence).
+ * Returns previous fence.
+ */
+struct dma_fence *sync_file_replace_fence(struct sync_file *sync_file,
+ struct dma_fence *fence)
+{
+ struct dma_fence *ret_fence = NULL;
+
+ if (sync_file->type != SYNC_FILE_TYPE_SEMAPHORE)
+ return NULL;
+
+ if (fence)
+ dma_fence_get(fence);
+
+ mutex_lock(&sync_file->lock);
+
+ ret_fence = sync_file_get_fence_locked(sync_file);
+ if (ret_fence) {
+ if (test_bit(POLL_ENABLED, &ret_fence->flags))
+ dma_fence_remove_callback(ret_fence, &sync_file->cb);
+ }
+
+ RCU_INIT_POINTER(sync_file->fence, fence);
+
+ mutex_unlock(&sync_file->lock);
+ return ret_fence;
+}
+EXPORT_SYMBOL(sync_file_replace_fence);
+
static int sync_file_set_fence(struct sync_file *sync_file,
struct dma_fence **fences, int num_fences)
{
@@ -280,6 +312,8 @@ static struct sync_file *sync_file_merge(const char *name, struct sync_file *a,
if (a->type != b->type)
return NULL;
+ if (a->type != SYNC_FILE_TYPE_FENCE)
+ return NULL;
if (!rcu_access_pointer(a->fence) ||
!rcu_access_pointer(b->fence))
diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h
index 4bf661b..245c7da 100644
--- a/include/linux/sync_file.h
+++ b/include/linux/sync_file.h
@@ -62,4 +62,6 @@ struct sync_file *sync_file_alloc(uint32_t type, uint32_t flags);
struct sync_file *sync_file_create(struct dma_fence *fence, uint32_t type, uint32_t flags);
struct dma_fence *sync_file_get_fence(int fd);
struct sync_file *sync_file_fdget(int fd);
+struct dma_fence *sync_file_replace_fence(struct sync_file *sync_file,
+ struct dma_fence *fence);
#endif /* _LINUX_SYNC_H */
diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
index f439cda..5f266e0 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -80,6 +80,20 @@ struct sync_file_info {
#define SYNC_FILE_TYPE_FENCE 0
/**
+ * DOC: SYNC_FILE_TYPE_SEMAPHORE - semaphore sync file object
+ *
+ * This is a sync file that operates like a Vulkan semaphore.
+ * The object should just be imported/exported but not use the
+ * sync file ioctls (except info).
+ * This object can have it's backing fence replaced multiple times.
+ * Each signal operation assigns a backing fence.
+ * Each wait operation waits on the current fence, and removes it.
+ * These operations should happen via driver command submission interfaces.
+ * This is useful for shared vulkan semaphores.
+ */
+#define SYNC_FILE_TYPE_SEMAPHORE 1
+
+/**
* struct sync_file_type - data returned from sync file type ioctl
* @type: sync_file type
* @flags: sync_file creation flags
--
2.9.3
