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.TH "BLK_INSERT_REQUEST" "9" "17 July 2003" "" ""

.SH NAME
blk_insert_request \- insert a special request in to a request queue
.SH SYNOPSIS
.sp
\fB
.sp
void blk_insert_request  (request_queue_t * \fIq\fB, struct request * \fIrq\fB, int \fIat_head\fB, void * \fIdata\fB);
\fR
.SH "ARGUMENTS"
.TP
\fB\fIq\fB\fR
request queue where request should be inserted
.TP
\fB\fIrq\fB\fR
request to be inserted
.TP
\fB\fIat_head\fB\fR
insert request at head or tail of queue
.TP
\fB\fIdata\fB\fR
private data
.SH "DESCRIPTION"
.PP
Many block devices need to execute commands asynchronously, so they don't
block the whole kernel from preemption during request execution.  This is
accomplished normally by inserting aritficial requests tagged as
REQ_SPECIAL in to the corresponding request queue, and letting them be
scheduled for actual execution by the request queue.
.PP
We have the option of inserting the head or the tail of the queue.
Typically we use the tail for new ioctls and so forth.  We use the head
of the queue for things like a QUEUE_FULL message from a device, or a
host that is unable to accept a particular command.
.SH "ABOUT THIS DOCUMENT"
.PP
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.
.PP
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.
.PP
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
.PP
For more details see the file COPYING in the source
distribution of Linux.
.PP
If you have comments on the formatting of this manpage, then please contact
Michael Still (mikal@stillhq.com).
.PP
This documentation was generated with kernel version 2.5.74.