In order to allow drivers to cleanly handled teardown we need to allow them to cancel pending async waits. To do this cleanly, we move allocation of sync_fence_waiter to the driver calling sync_async_wait().
Signed-off-by: Erik Gilling konkers@android.com --- drivers/base/sync.c | 46 +++++++++++++++++++++++++++++++--------------- include/linux/sync.h | 36 +++++++++++++++++++++++++++++------- 2 files changed, 60 insertions(+), 22 deletions(-)
diff --git a/drivers/base/sync.c b/drivers/base/sync.c index cc40e4c..5e89195 100644 --- a/drivers/base/sync.c +++ b/drivers/base/sync.c @@ -421,33 +421,22 @@ static void sync_fence_signal_pt(struct sync_pt *pt) container_of(pos, struct sync_fence_waiter, waiter_list);
- waiter->callback(fence, waiter->callback_data); list_del(pos); - kfree(waiter); + waiter->callback(fence, waiter); } wake_up(&fence->wq); } }
int sync_fence_wait_async(struct sync_fence *fence, - void (*callback)(struct sync_fence *, void *data), - void *callback_data) + struct sync_fence_waiter *waiter) { - struct sync_fence_waiter *waiter; unsigned long flags; int err = 0;
- waiter = kzalloc(sizeof(struct sync_fence_waiter), GFP_KERNEL); - if (waiter == NULL) - return -ENOMEM; - - waiter->callback = callback; - waiter->callback_data = callback_data; - spin_lock_irqsave(&fence->waiter_list_lock, flags);
if (fence->status) { - kfree(waiter); err = fence->status; goto out; } @@ -459,6 +448,34 @@ out: return err; }
+int sync_fence_cancel_async(struct sync_fence *fence, + struct sync_fence_waiter *waiter) +{ + struct list_head *pos; + struct list_head *n; + unsigned long flags; + int ret = -ENOENT; + + spin_lock_irqsave(&fence->waiter_list_lock, flags); + /* + * Make sure waiter is still in waiter_list because it is possible for + * the waiter to be removed from the list while the callback is still + * pending. + */ + list_for_each_safe(pos, n, &fence->waiter_list_head) { + struct sync_fence_waiter *list_waiter = + container_of(pos, struct sync_fence_waiter, + waiter_list); + if (list_waiter == waiter) { + list_del(pos); + ret = 0; + break; + } + } + spin_unlock_irqrestore(&fence->waiter_list_lock, flags); + return ret; +} + int sync_fence_wait(struct sync_fence *fence, long timeout) { int err; @@ -739,8 +756,7 @@ static void sync_print_fence(struct seq_file *s, struct sync_fence *fence) container_of(pos, struct sync_fence_waiter, waiter_list);
- seq_printf(s, "waiter %pF %p\n", waiter->callback, - waiter->callback_data); + seq_printf(s, "waiter %pF\n", waiter->callback); } spin_unlock_irqrestore(&fence->waiter_list_lock, flags); } diff --git a/include/linux/sync.h b/include/linux/sync.h index 6db0528..1beaa53 100644 --- a/include/linux/sync.h +++ b/include/linux/sync.h @@ -161,6 +161,10 @@ struct sync_fence { struct list_head sync_fence_list; };
+struct sync_fence_waiter; +typedef void (*sync_callback_t)(struct sync_fence *fence, + struct sync_fence_waiter *waiter); + /** * struct sync_fence_waiter - metadata for asynchronous waiter on a fence * @waiter_list: membership in sync_fence.waiter_list_head @@ -170,10 +174,15 @@ struct sync_fence { struct sync_fence_waiter { struct list_head waiter_list;
- void (*callback)(struct sync_fence *fence, void *data); - void *callback_data; + sync_callback_t callback; };
+static inline void sync_fence_waiter_init(struct sync_fence_waiter *waiter, + sync_callback_t callback) +{ + waiter->callback = callback; +} + /* * API for sync_timeline implementers */ @@ -286,16 +295,29 @@ void sync_fence_install(struct sync_fence *fence, int fd); /** * sync_fence_wait_async() - registers and async wait on the fence * @fence: fence to wait on - * @callback: callback - * @callback_data data to pass to the callback + * @waiter: waiter callback struck * * Returns 1 if @fence has already signaled. * - * Registers a callback to be called when @fence signals or has an error + * Registers a callback to be called when @fence signals or has an error. + * @waiter should be initialized with sync_fence_waiter_init(). */ int sync_fence_wait_async(struct sync_fence *fence, - void (*callback)(struct sync_fence *, void *data), - void *callback_data); + struct sync_fence_waiter *waiter); + +/** + * sync_fence_cancel_async() - cancels an async wait + * @fence: fence to wait on + * @waiter: waiter callback struck + * + * returns 0 if waiter was removed from fence's async waiter list. + * returns -ENOENT if waiter was not found on fence's async waiter list. + * + * Cancels a previously registered async wait. Will fail gracefully if + * @waiter was never registered or if @fence has already signaled @waiter. + */ +int sync_fence_cancel_async(struct sync_fence *fence, + struct sync_fence_waiter *waiter);
/** * sync_fence_wait() - wait on fence