Ping!
Any more comments or can I get an rb on this? Sorry for the hurry, but I
want to get this our of my feet.
Regards,
Christian.
Silence is golden. Except when you have kids or wait for code review,
then silence is suspicious.
On 27.10.2015 17:04, Christian König wrote:
From: Christian König <christian.koenig@xxxxxxx>
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@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/dma-buf/fence.c | 98 +++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/fence.h | 3 +-
2 files changed, 100 insertions(+), 1 deletion(-)
diff --git a/drivers/dma-buf/fence.c b/drivers/dma-buf/fence.c
index 50ef8bd..7b05dbe 100644
--- 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 ddc0f26..bb52201 100644
--- a/include/linux/fence.h
+++ b/include/linux/fence.h
@@ -321,7 +321,8 @@ 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
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