diff options
Diffstat (limited to 'drivers/gpu/drm/amd/scheduler/spsc_queue.h')
-rw-r--r-- | drivers/gpu/drm/amd/scheduler/spsc_queue.h | 121 |
1 files changed, 0 insertions, 121 deletions
diff --git a/drivers/gpu/drm/amd/scheduler/spsc_queue.h b/drivers/gpu/drm/amd/scheduler/spsc_queue.h deleted file mode 100644 index 5902f35ce759..000000000000 --- a/drivers/gpu/drm/amd/scheduler/spsc_queue.h +++ /dev/null @@ -1,121 +0,0 @@ -/* - * Copyright 2017 Advanced Micro Devices, Inc. - * - * Permission is hereby granted, free of charge, to any person obtaining a - * copy of this software and associated documentation files (the "Software"), - * to deal in the Software without restriction, including without limitation - * the rights to use, copy, modify, merge, publish, distribute, sublicense, - * and/or sell copies of the Software, and to permit persons to whom the - * Software is furnished to do so, subject to the following conditions: - * - * The above copyright notice and this permission notice shall be included in - * all copies or substantial portions of the Software. - * - * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR - * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL - * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR - * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, - * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR - * OTHER DEALINGS IN THE SOFTWARE. - * - */ - -#ifndef AMD_SCHEDULER_SPSC_QUEUE_H_ -#define AMD_SCHEDULER_SPSC_QUEUE_H_ - -#include <linux/atomic.h> - -/** SPSC lockless queue */ - -struct spsc_node { - - /* Stores spsc_node* */ - struct spsc_node *next; -}; - -struct spsc_queue { - - struct spsc_node *head; - - /* atomic pointer to struct spsc_node* */ - atomic_long_t tail; - - atomic_t job_count; -}; - -static inline void spsc_queue_init(struct spsc_queue *queue) -{ - queue->head = NULL; - atomic_long_set(&queue->tail, (long)&queue->head); - atomic_set(&queue->job_count, 0); -} - -static inline struct spsc_node *spsc_queue_peek(struct spsc_queue *queue) -{ - return queue->head; -} - -static inline int spsc_queue_count(struct spsc_queue *queue) -{ - return atomic_read(&queue->job_count); -} - -static inline bool spsc_queue_push(struct spsc_queue *queue, struct spsc_node *node) -{ - struct spsc_node **tail; - - node->next = NULL; - - preempt_disable(); - - tail = (struct spsc_node **)atomic_long_xchg(&queue->tail, (long)&node->next); - WRITE_ONCE(*tail, node); - atomic_inc(&queue->job_count); - - /* - * In case of first element verify new node will be visible to the consumer - * thread when we ping the kernel thread that there is new work to do. - */ - smp_wmb(); - - preempt_enable(); - - return tail == &queue->head; -} - - -static inline struct spsc_node *spsc_queue_pop(struct spsc_queue *queue) -{ - struct spsc_node *next, *node; - - /* Verify reading from memory and not the cache */ - smp_rmb(); - - node = READ_ONCE(queue->head); - - if (!node) - return NULL; - - next = READ_ONCE(node->next); - WRITE_ONCE(queue->head, next); - - if (unlikely(!next)) { - /* slowpath for the last element in the queue */ - - if (atomic_long_cmpxchg(&queue->tail, - (long)&node->next, (long) &queue->head) != (long)&node->next) { - /* Updating tail failed wait for new next to appear */ - do { - smp_rmb(); - } while (unlikely(!(queue->head = READ_ONCE(node->next)))); - } - } - - atomic_dec(&queue->job_count); - return node; -} - - - -#endif /* AMD_SCHEDULER_SPSC_QUEUE_H_ */ |