static void *reader_thread (void *cache_ptr)
{
struct tags_cache *c = (struct tags_cache *)cache_ptr;
int curr_queue = 0; /* index of the queue from where we will get the
next request */
logit ("Tags reader thread started");
LOCK (c->mutex);
while (!c->stop_reader_thread) {
int i;
char *request_file;
int tags_sel = 0;
/* find the queue with a request waiting, begin searching at
* curr_queue: we want to get one request from each queue,
* and then move to the next non-empty queue */
i = curr_queue;
while (i < CLIENTS_MAX && request_queue_empty(&c->queues[i]))
i++;
if (i == CLIENTS_MAX) {
i = 0;
while (i < curr_queue
&& request_queue_empty(&c->queues[i]))
i++;
if (i == curr_queue) {
debug ("All queues empty, waiting");
pthread_cond_wait (&c->request_cond, &c->mutex);
continue;
}
}
curr_queue = i;
request_file = request_queue_pop (&c->queues[curr_queue],
&tags_sel);
UNLOCK (c->mutex);
tags_cache_read_add (c, curr_queue, request_file, tags_sel);
free (request_file);
LOCK (c->mutex);
if (++curr_queue == CLIENTS_MAX)
curr_queue = 0;
}
UNLOCK (c->mutex);
logit ("Exiting tags reader thread");
return NULL;
}
/*
* Submit an I/O request on a buffer.
*/
int submit_block(int rw, struct buffer *buf)
{
struct block_device *dev = get_device(buf->b_dev);
struct request *req = make_request(rw, buf);
buffer_lock(buf);
if (request_queue_empty(dev))
dev->handle_request(dev, req);
else
list_add_tail(&req->chain, &dev->requests);
return 0;
}
/*
* Block drivers call this function to signal completion of an I/O request.
*/
void block_request_completed(struct block_device *dev, struct request *req)
{
req->buf->b_flags |= BUF_UPTODATE;
release_buffer(req->buf);
buffer_unlock(req->buf);
slab_free(request_cachep, req);
if (request_queue_empty(dev))
return;
req = list_first_entry(&dev->requests, struct request, chain);
list_del(&req->chain);
dev->handle_request(dev, req);
}
