From: Gustavo Padovan <gustavo.pado...@collabora.co.uk>
Signalling doesn't need to be enabled at sync_file creation, it is only
required if userspace waiting the fence to signal through poll().
Thus we delay fence_add_callback() until poll is called. It only adds the
callback the first time poll() is called. This avoid re-adding the same
callback multiple times.
Signed-off-by: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
---
drivers/dma-buf/sync_file.c | 36 +++++++++++++++++++++++-------------
include/linux/fence.h | 12 ++++++++++++
2 files changed, 35 insertions(+), 13 deletions(-)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 00e9186..59f3445 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -91,9 +91,7 @@ struct sync_file *sync_file_create(struct fence *fence)
sync_file->cbs[0].fence = fence;
sync_file->cbs[0].sync_file = sync_file;
- if (fence_add_callback(fence, &sync_file->cbs[0].cb,
- fence_check_cb_func))
- atomic_dec(&sync_file->status);
+ INIT_LIST_HEAD(&sync_file->cbs[0].cb.node);
sync_file_debug_add(sync_file);
return sync_file;
@@ -130,8 +128,7 @@ static void sync_file_add_pt(struct sync_file *sync_file,
int *i,
sync_file->cbs[*i].fence = fence;
sync_file->cbs[*i].sync_file = sync_file;
- if (!fence_add_callback(fence, &sync_file->cbs[*i].cb,
- fence_check_cb_func)) {
+ if (!fence_is_signaled(fence)) {
fence_get(fence);
(*i)++;
}
@@ -212,11 +209,8 @@ static void sync_file_free(struct kref *kref)
kref);
int i;
- for (i = 0; i < sync_file->num_fences; ++i) {
- fence_remove_callback(sync_file->cbs[i].fence,
- &sync_file->cbs[i].cb);
+ for (i = 0; i < sync_file->num_fences; ++i)
fence_put(sync_file->cbs[i].fence);
- }
sync_file_debug_remove(sync_file);
kfree(sync_file);
@@ -233,17 +227,33 @@ static int sync_file_release(struct inode *inode, struct
file *file)
static unsigned int sync_file_poll(struct file *file, poll_table *wait)
{
struct sync_file *sync_file = file->private_data;
- int status;
+ int status, i;
poll_wait(file, &sync_file->wq, wait);
+ for (i = 0 ; i < sync_file->num_fences ; i++) {
+ if (fence_is_enabled(sync_file->cbs[i].fence))
+ continue;
+
+ if (fence_add_callback(sync_file->cbs[i].fence,
+ &sync_file->cbs[i].cb,
+ fence_check_cb_func))
+ atomic_dec(&sync_file->status);
+ }
+
status = atomic_read(&sync_file->status);
- if (!status)
- return POLLIN;
+ if (status > 0)
+ return 0;
+
+ for (i = 0 ; i < sync_file->num_fences ; i++)
+ fence_remove_callback(sync_file->cbs[i].fence,
+ &sync_file->cbs[i].cb);
+
if (status < 0)
return POLLERR;
- return 0;
+
+ return POLLIN;
}
static long sync_file_ioctl_merge(struct sync_file *sync_file,
diff --git a/include/linux/fence.h b/include/linux/fence.h
index 523ea3f..95a70b2 100644
--- a/include/linux/fence.h
+++ b/include/linux/fence.h
@@ -283,6 +283,18 @@ fence_is_signaled(struct fence *fence)
}
/**
+ * fence_is_enabled - return an indication if signalling is enabled
+ * @fence: [in] the fence to check
+ *
+ * Returns true if signalling was already enabled, false if not.
+ */
+static inline bool
+fence_is_enabled(struct fence *fence)
+{
+ return test_bit(FENCE_FLAG_ENABLE_SIGNAL_BIT, &fence->flags);
+}
+
+/**
* fence_is_later - return if f1 is chronologically later than f2
* @f1: [in] the first fence from the same context
* @f2: [in] the second fence from the same context
--
2.5.5
