dma-buf/fence: add fence_wait_any_timeout function v2

Waiting for the first fence in an array of fences to signal.

This is useful for device driver specific resource managers
and also Vulkan needs something similar.

v2: more parameter checks, handling for timeout==0,
    remove NULL entry support, better callback removal.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

diff --git a/drivers/dma-buf/fence.c b/drivers/dma-buf/fence.c
index 50ef8bd8708ba69d93808510c9a8be473d377d7c..7b05dbe9b2964fd8c431dde0512a0ba2f4fd6ff2 100644 (file)
--- a/drivers/dma-buf/fence.c
+++ b/drivers/dma-buf/fence.c
@@ -397,6 +397,104 @@ out:
 }
 EXPORT_SYMBOL(fence_default_wait);
 
+static bool
+fence_test_signaled_any(struct fence **fences, uint32_t count)
+{
+       int i;
+
+       for (i = 0; i < count; ++i) {
+               struct fence *fence = fences[i];
+               if (test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->flags))
+                       return true;
+       }
+       return false;
+}
+
+/**
+ * fence_wait_any_timeout - sleep until any fence gets signaled
+ * or until timeout elapses
+ * @fences:    [in]    array of fences to wait on
+ * @count:     [in]    number of fences to wait on
+ * @intr:      [in]    if true, do an interruptible wait
+ * @timeout:   [in]    timeout value in jiffies, or MAX_SCHEDULE_TIMEOUT
+ *
+ * Returns -EINVAL on custom fence wait implementation, -ERESTARTSYS if
+ * interrupted, 0 if the wait timed out, or the remaining timeout in jiffies
+ * on success.
+ *
+ * Synchronous waits for the first fence in the array to be signaled. The
+ * caller needs to hold a reference to all fences in the array, otherwise a
+ * fence might be freed before return, resulting in undefined behavior.
+ */
+signed long
+fence_wait_any_timeout(struct fence **fences, uint32_t count,
+                      bool intr, signed long timeout)
+{
+       struct default_wait_cb *cb;
+       signed long ret = timeout;
+       unsigned i;
+
+       if (WARN_ON(!fences || !count || timeout < 0))
+               return -EINVAL;
+
+       if (timeout == 0) {
+               for (i = 0; i < count; ++i)
+                       if (fence_is_signaled(fences[i]))
+                               return 1;
+
+               return 0;
+       }
+
+       cb = kcalloc(count, sizeof(struct default_wait_cb), GFP_KERNEL);
+       if (cb == NULL) {
+               ret = -ENOMEM;
+               goto err_free_cb;
+       }
+
+       for (i = 0; i < count; ++i) {
+               struct fence *fence = fences[i];
+
+               if (fence->ops->wait != fence_default_wait) {
+                       ret = -EINVAL;
+                       goto fence_rm_cb;
+               }
+
+               cb[i].task = current;
+               if (fence_add_callback(fence, &cb[i].base,
+                                      fence_default_wait_cb)) {
+                       /* This fence is already signaled */
+                       goto fence_rm_cb;
+               }
+       }
+
+       while (ret > 0) {
+               if (intr)
+                       set_current_state(TASK_INTERRUPTIBLE);
+               else
+                       set_current_state(TASK_UNINTERRUPTIBLE);
+
+               if (fence_test_signaled_any(fences, count))
+                       break;
+
+               ret = schedule_timeout(ret);
+
+               if (ret > 0 && intr && signal_pending(current))
+                       ret = -ERESTARTSYS;
+       }
+
+       __set_current_state(TASK_RUNNING);
+
+fence_rm_cb:
+       while (i-- > 0)
+               fence_remove_callback(fences[i], &cb[i].base);
+
+err_free_cb:
+       kfree(cb);
+
+       return ret;
+}
+EXPORT_SYMBOL(fence_wait_any_timeout);
+
 /**
  * fence_init - Initialize a custom fence.
  * @fence:     [in]    the fence to initialize

diff --git a/include/linux/fence.h b/include/linux/fence.h
index 39efee130d2b01c3c45ed09e46e26734ec240be8..a4084d6bb851c7f86ba8b3b777c484b60ff399de 100644 (file)
--- a/include/linux/fence.h
+++ b/include/linux/fence.h
@@ -305,7 +305,8 @@ static inline struct fence *fence_later(struct fence *f1, struct fence *f2)
 }
 
 signed long fence_wait_timeout(struct fence *, bool intr, signed long timeout);
-
+signed long fence_wait_any_timeout(struct fence **fences, uint32_t count,
+                                  bool intr, signed long timeout);
 
 /**
  * fence_wait - sleep until the fence gets signaled