BLK_INIT_QUEUE

Section: (9)
Updated: 07 August 2003
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NAME

blk_init_queue - prepare a request queue for use with a block device  

SYNOPSIS

int blk_init_queue (request_queue_t * q, request_fn_proc * rfn, spinlock_t * lock);  

ARGUMENTS

q
The &request_queue_t to be initialised
rfn
The function to be called to process requests that have been placed on the queue.
lock
-- undescribed --
 

DESCRIPTION

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 pressure.

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 request queue.  

NOTE

blk_init_queue must be paired with a blk_cleanup_queue call when the block device is deactivated (such as at module unload).  

ABOUT THIS DOCUMENT

This documentation is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

For more details see the file COPYING in the source distribution of Linux.

If you have comments on the formatting of this manpage, then please contact Michael Still (mikal@stillhq.com).

This documentation was generated with kernel version 2.6.0.


 

Index

NAME
SYNOPSIS
ARGUMENTS
DESCRIPTION
NOTE
ABOUT THIS DOCUMENT

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Time: 04:27:40 GMT, August 07, 2003