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.
v2: change replace fence API to have a return value,
don't allow polling on semaphore objects,
don't worry about polling when replacing fences (since
we don't allow polling anymore).
switch APIs to one to retreive a fence from a sync_file
to make AMDGPU implementation more robust.
Signed-off-by: Dave Airlie <airlied@xxxxxxxxxx>
---
drivers/dma-buf/sync_file.c | 73 ++++++++++++++++++++++++++++++++++++------
include/linux/sync_file.h | 4 +++
include/uapi/linux/sync_file.h | 14 ++++++++
3 files changed, 81 insertions(+), 10 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 57ea7c7..01c12e7 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;
}
@@ -165,6 +165,28 @@ struct sync_file *sync_file_fdget(int fd)
EXPORT_SYMBOL(sync_file_fdget);
/**
+ * sync_file_get_fence_from_sync_file - get the fence related to the sync_file
+ * @sync_file: sync_file fd to get the fence from
+ *
+ * Returns a fence that represents all fence in the sync_file. On error NULL is returned.
+ */
+struct dma_fence *sync_file_get_fence_from_sync_file(struct sync_file *sync_file)
+{
+ struct dma_fence *fence;
+
+ if (!rcu_access_pointer(sync_file->fence)) {
+ fput(sync_file->file);
+ return NULL;
+ }
+
+ rcu_read_lock();
+ fence = dma_fence_get_rcu_safe(&sync_file->fence);
+ rcu_read_unlock();
+ return fence;
+}
+EXPORT_SYMBOL(sync_file_get_fence_from_sync_file);
+
+/**
* sync_file_get_fence - get the fence related to the sync_file fd
* @fd: sync_file fd to get the fence from
*
@@ -180,14 +202,7 @@ struct dma_fence *sync_file_get_fence(int fd)
if (!sync_file)
return NULL;
- if (!rcu_access_pointer(sync_file->fence)) {
- fput(sync_file->file);
- return NULL;
- }
-
- rcu_read_lock();
- fence = dma_fence_get_rcu_safe(&sync_file->fence);
- rcu_read_unlock();
+ fence = sync_file_get_fence_from_sync_file(sync_file);
fput(sync_file->file);
@@ -202,6 +217,39 @@ 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.
+ */
+int sync_file_replace_fence(struct sync_file *sync_file,
+ struct dma_fence *fence,
+ struct dma_fence **old_fence)
+{
+ struct dma_fence *ret_fence = NULL;
+
+ /* don't allow replace on fence sync files */
+ if (sync_file->type != SYNC_FILE_TYPE_SEMAPHORE)
+ return -EINVAL;
+
+ if (fence == sync_file->fence)
+ return -EINVAL;
+
+ if (fence)
+ dma_fence_get(fence);
+
+ mutex_lock(&sync_file->lock);
+
+ ret_fence = sync_file_get_fence_locked(sync_file);
+ RCU_INIT_POINTER(sync_file->fence, fence);
+
+ mutex_unlock(&sync_file->lock);
+ *old_fence = ret_fence;
+ return 0;
+}
+EXPORT_SYMBOL(sync_file_replace_fence);
+
static int sync_file_set_fence(struct sync_file *sync_file,
struct dma_fence **fences, int num_fences)
{
@@ -406,6 +454,10 @@ static unsigned int sync_file_poll(struct file *file, poll_table *wait)
unsigned int ret_val = 0;
struct dma_fence *fence;
+ /* ban polls on the sync file semaphores */
+ if (!sync_file || sync_file->type != SYNC_FILE_TYPE_FENCE)
+ return POLLERR | POLLNVAL;
+
poll_wait(file, &sync_file->wq, wait);
mutex_lock(&sync_file->lock);
@@ -453,7 +505,8 @@ static long sync_file_ioctl_merge(struct sync_file *sync_file,
data.name[sizeof(data.name) - 1] = '\0';
- if (sync_file->type != fence2->type) {
+ if (sync_file->type != fence2->type ||
+ sync_file->type != SYNC_FILE_TYPE_FENCE) {
err = -EINVAL;
goto err_put_fd;
}
diff --git a/include/linux/sync_file.h b/include/linux/sync_file.h
index 4bf661b..14dff25 100644
--- a/include/linux/sync_file.h
+++ b/include/linux/sync_file.h
@@ -61,5 +61,9 @@ int sync_file_validate_type_flags(uint32_t type, uint32_t flags);
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 dma_fence *sync_file_get_fence_from_sync_file(struct sync_file *sync_file);
struct sync_file *sync_file_fdget(int fd);
+int sync_file_replace_fence(struct sync_file *sync_file,
+ struct dma_fence *fence,
+ struct dma_fence **old_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
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