From a519435a96597d8cd96123246fea4ae5a6c90b02 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Christian=20K=C3=B6nig?= Date: Tue, 20 Oct 2015 16:34:16 +0200 Subject: [PATCH] dma-buf/fence: add fence_wait_any_timeout function v2 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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 Reviewed-by: Alex Deucher Reviewed-by: Maarten Lankhorst --- 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 50ef8bd8708b..7b05dbe9b296 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 39efee130d2b..a4084d6bb851 100644 --- 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 -- 2.30.2