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authorChris Wilson <chris@chris-wilson.co.uk>2019-08-17 16:30:22 +0100
committerChris Wilson <chris@chris-wilson.co.uk>2019-08-17 18:46:33 +0100
commitf2cb60e9a3881e679465f84140754bc9d29956ea (patch)
tree62b3bc44752ee688d651354aedf6742ffb8b51e0 /drivers/dma-buf
parent0fc89b6802ba1fcc561b0c906e0cefd384e3b2e5 (diff)
downloadlinux-f2cb60e9a3881e679465f84140754bc9d29956ea.tar.bz2
dma-fence: Store the timestamp in the same union as the cb_list
The timestamp and the cb_list are mutually exclusive, the cb_list can only be added to prior to being signaled (and once signaled we drain), while the timestamp is only valid upon being signaled. Both the timestamp and the cb_list are only valid while the fence is alive, and as soon as no references are held can be replaced by the rcu_head. By reusing the union for the timestamp, we squeeze the base dma_fence struct to 64 bytes on x86-64. v2: Sort the union chronologically Suggested-by: Christian König <christian.koenig@amd.com> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Christian König <christian.koenig@amd.com> Acked-by: Christian König <christian.koenig@amd.com>. Link: https://patchwork.freedesktop.org/patch/msgid/20190817153022.5749-1-chris@chris-wilson.co.uk
Diffstat (limited to 'drivers/dma-buf')
-rw-r--r--drivers/dma-buf/dma-fence.c16
1 files changed, 9 insertions, 7 deletions
diff --git a/drivers/dma-buf/dma-fence.c b/drivers/dma-buf/dma-fence.c
index 8a6d0250285d..2c136aee3e79 100644
--- a/drivers/dma-buf/dma-fence.c
+++ b/drivers/dma-buf/dma-fence.c
@@ -129,6 +129,7 @@ EXPORT_SYMBOL(dma_fence_context_alloc);
int dma_fence_signal_locked(struct dma_fence *fence)
{
struct dma_fence_cb *cur, *tmp;
+ struct list_head cb_list;
lockdep_assert_held(fence->lock);
@@ -136,16 +137,16 @@ int dma_fence_signal_locked(struct dma_fence *fence)
&fence->flags)))
return -EINVAL;
+ /* Stash the cb_list before replacing it with the timestamp */
+ list_replace(&fence->cb_list, &cb_list);
+
fence->timestamp = ktime_get();
set_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &fence->flags);
trace_dma_fence_signaled(fence);
- if (!list_empty(&fence->cb_list)) {
- list_for_each_entry_safe(cur, tmp, &fence->cb_list, node) {
- INIT_LIST_HEAD(&cur->node);
- cur->func(fence, cur);
- }
- INIT_LIST_HEAD(&fence->cb_list);
+ list_for_each_entry_safe(cur, tmp, &cb_list, node) {
+ INIT_LIST_HEAD(&cur->node);
+ cur->func(fence, cur);
}
return 0;
@@ -231,7 +232,8 @@ void dma_fence_release(struct kref *kref)
trace_dma_fence_destroy(fence);
- if (WARN(!list_empty(&fence->cb_list),
+ if (WARN(!list_empty(&fence->cb_list) &&
+ !test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->flags),
"Fence %s:%s:%llx:%llx released with pending signals!\n",
fence->ops->get_driver_name(fence),
fence->ops->get_timeline_name(fence),