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17 * ALTERNATIVELY, this software may be distributed under the terms of the
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34 #include "vchiq_util.h"
35 #include "vchiq_killable.h"
37 static inline int is_pow2(int i)
39 return i && !(i & (i - 1));
42 int vchiu_queue_init(VCHIU_QUEUE_T *queue, int size)
44 WARN_ON(!is_pow2(size));
49 queue->initialized = 1;
51 sema_init(&queue->pop, 0);
52 sema_init(&queue->push, 0);
54 queue->storage = kcalloc(size, sizeof(VCHIQ_HEADER_T *), GFP_KERNEL);
55 if (!queue->storage) {
56 vchiu_queue_delete(queue);
62 void vchiu_queue_delete(VCHIU_QUEUE_T *queue)
64 kfree(queue->storage);
67 int vchiu_queue_is_empty(VCHIU_QUEUE_T *queue)
69 return queue->read == queue->write;
72 int vchiu_queue_is_full(VCHIU_QUEUE_T *queue)
74 return queue->write == queue->read + queue->size;
77 void vchiu_queue_push(VCHIU_QUEUE_T *queue, VCHIQ_HEADER_T *header)
79 if (!queue->initialized)
82 while (queue->write == queue->read + queue->size) {
83 if (down_interruptible(&queue->pop) != 0)
84 flush_signals(current);
88 * Write to queue->storage must be visible after read from
93 queue->storage[queue->write & (queue->size - 1)] = header;
96 * Write to queue->storage must be visible before write to
106 VCHIQ_HEADER_T *vchiu_queue_peek(VCHIU_QUEUE_T *queue)
108 while (queue->write == queue->read) {
109 if (down_interruptible(&queue->push) != 0)
110 flush_signals(current);
113 up(&queue->push); // We haven't removed anything from the queue.
116 * Read from queue->storage must be visible after read from
121 return queue->storage[queue->read & (queue->size - 1)];
124 VCHIQ_HEADER_T *vchiu_queue_pop(VCHIU_QUEUE_T *queue)
126 VCHIQ_HEADER_T *header;
128 while (queue->write == queue->read) {
129 if (down_interruptible(&queue->push) != 0)
130 flush_signals(current);
134 * Read from queue->storage must be visible after read from
139 header = queue->storage[queue->read & (queue->size - 1)];
142 * Read from queue->storage must be visible before write to