Provided by: linux-doc-2.6.15_2.6.15-23.39_all
blk_init_queue - prepare a request queue for use with a block device
request_queue_t * blk_init_queue (request_fn_proc * rfn,
spinlock_t * lock);
rfn The function to be called to process requests that have been
placed on the queue.
lock Request queue spin lock
If a block device wishes to use the standard request handling
procedures, which sorts requests and coalesces adjacent requests, then
it must call blk_init_queue. The function rfn will be called when there
are requests on the queue that need to be processed. If the device
supports plugging, then rfn may not be called immediately when requests
are available on the queue, but may be called at some time later
instead. Plugged queues are generally unplugged when a buffer belonging
to one of the requests on the queue is needed, or due to memory
rfn is not required, or even expected, to remove all requests off the
queue, but only as many as it can handle at a time. If it does leave
requests on the queue, it is responsible for arranging that the
requests get dealt with eventually.
The queue spin lock must be held while manipulating the requests on the
Function returns a pointer to the initialized request queue, or NULL if
it didn’t succeed.
blk_init_queue must be paired with a blk_cleanup_queue call when the
block device is deactivated (such as at module unload).