[Intel-gfx] [PATCH v2] dma-buf/sw_sync: Separate signal/timeline locks
Chris Wilson
chris at chris-wilson.co.uk
Tue Jul 14 20:14:07 UTC 2020
Since we decouple the sync_pt from the timeline tree upon release, in
order to allow releasing the sync_pt from a signal callback we need to
separate the sync_pt signaling lock from the timeline tree lock.
v2: Mark up the unlocked read of the current timeline value.
Suggested-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
---
drivers/dma-buf/sw_sync.c | 33 ++++++++++++++++++++-------------
drivers/dma-buf/sync_debug.h | 2 ++
2 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/drivers/dma-buf/sw_sync.c b/drivers/dma-buf/sw_sync.c
index 807c82148062..5851bf7076d0 100644
--- a/drivers/dma-buf/sw_sync.c
+++ b/drivers/dma-buf/sw_sync.c
@@ -132,24 +132,32 @@ static void timeline_fence_release(struct dma_fence *fence)
{
struct sync_pt *pt = dma_fence_to_sync_pt(fence);
struct sync_timeline *parent = dma_fence_parent(fence);
- unsigned long flags;
- spin_lock_irqsave(fence->lock, flags);
if (!list_empty(&pt->link)) {
- list_del(&pt->link);
- rb_erase(&pt->node, &parent->pt_tree);
+ unsigned long flags;
+
+ spin_lock_irqsave(&parent->lock, flags);
+ if (!list_empty(&pt->link)) {
+ list_del(&pt->link);
+ rb_erase(&pt->node, &parent->pt_tree);
+ }
+ spin_unlock_irqrestore(&parent->lock, flags);
}
- spin_unlock_irqrestore(fence->lock, flags);
sync_timeline_put(parent);
dma_fence_free(fence);
}
-static bool timeline_fence_signaled(struct dma_fence *fence)
+static int timeline_value(struct dma_fence *fence)
{
- struct sync_timeline *parent = dma_fence_parent(fence);
+ return READ_ONCE(dma_fence_parent(fence)->value);
+}
- return !__dma_fence_is_later(fence->seqno, parent->value, fence->ops);
+static bool timeline_fence_signaled(struct dma_fence *fence)
+{
+ return !__dma_fence_is_later(fence->seqno,
+ timeline_value(fence),
+ fence->ops);
}
static bool timeline_fence_enable_signaling(struct dma_fence *fence)
@@ -166,9 +174,7 @@ static void timeline_fence_value_str(struct dma_fence *fence,
static void timeline_fence_timeline_value_str(struct dma_fence *fence,
char *str, int size)
{
- struct sync_timeline *parent = dma_fence_parent(fence);
-
- snprintf(str, size, "%d", parent->value);
+ snprintf(str, size, "%d", timeline_value(fence));
}
static const struct dma_fence_ops timeline_fence_ops = {
@@ -252,12 +258,13 @@ static struct sync_pt *sync_pt_create(struct sync_timeline *obj,
return NULL;
sync_timeline_get(obj);
- dma_fence_init(&pt->base, &timeline_fence_ops, &obj->lock,
+ spin_lock_init(&pt->lock);
+ dma_fence_init(&pt->base, &timeline_fence_ops, &pt->lock,
obj->context, value);
INIT_LIST_HEAD(&pt->link);
spin_lock_irq(&obj->lock);
- if (!dma_fence_is_signaled_locked(&pt->base)) {
+ if (!dma_fence_is_signaled(&pt->base)) {
struct rb_node **p = &obj->pt_tree.rb_node;
struct rb_node *parent = NULL;
diff --git a/drivers/dma-buf/sync_debug.h b/drivers/dma-buf/sync_debug.h
index 6176e52ba2d7..fd073fc32329 100644
--- a/drivers/dma-buf/sync_debug.h
+++ b/drivers/dma-buf/sync_debug.h
@@ -55,11 +55,13 @@ static inline struct sync_timeline *dma_fence_parent(struct dma_fence *fence)
* @base: base fence object
* @link: link on the sync timeline's list
* @node: node in the sync timeline's tree
+ * @lock: fence signaling lock
*/
struct sync_pt {
struct dma_fence base;
struct list_head link;
struct rb_node node;
+ spinlock_t lock;
};
extern const struct file_operations sw_sync_debugfs_fops;
--
2.20.1
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