lis_unregister_strmod.9

7号信令功能代码,为开源代码

'\" tr
.\" -*- nroff -*-
.\"
.\" @(#) lis_unregister_strmod.9,v 1.1.4.1 2004/01/12 23:33:08 brian Exp
.\"
.\" =========================================================================
.\"
.\" Copyright (C) 2001-2004  OpenSS7 Corp. <www.openss7.com>
.\"
.\" All Rights Reserved.
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one
.\" 
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date.  The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein.  The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\" 
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" =========================================================================
.\"
.\" Modified 2004/01/12 23:33:08 by brian
.\"
.\" =========================================================================
.so lis.macros
.R1
bracket-label "\fR[\fB" "\fR]" "\fR, \fB"
no-default-database
database lis.refs
accumulate
move-punctuation
abbreviate A
join-authors ", " ", " " and "
et-al " et al" 2 3
abbreviate-label-ranges ".."
sort-adjacent-labels
.R2
.\"
.\"
.TH LIS_UNREGISTER_STRMOD 9 "2004/01/12 23:33:08" "LiS-2_16_18-8" "Linux STREAMS DDI/DKI"
.SH NAME
.B lis_unregister_strmod
\- deregister a \fISTREAMS\fR module
.SH SYNOPSIS
.PP
.B #include <sys/stream.h>
.HP 8
.BI "int " retval " = lis_unregister_strmod(struct streamtab *" strtab );
.SH DESCRIPTION
.PP
.BR lis_unregister_strmod ()
deregisters a
.IR STREAMS (4)
module previoulsy registered with
.BR lis_register_strmod (9).
.PP
.BR lis_unregister_strmod ()
removes the
.IR STREAMS (4)
module identified by
.I strtab
from all autopush lists, and removes the module from the
.IR STREAMS (4)
module switch
table.
Subsequent attempts to push the module will fail unless the module is
configured for demand loading (see
.IR "\*(lqCAVEATS\*(rq" ,
below).
.PP
For demand loaded
.IR STREAMS (4)
modules,
.BR lis_unregister_strmod ()
is normally and properly called from within the
.B Linux
kernel module's
.B init_module
routine.
.SH "RETURN VALUES"
.PP
Upon success,
.BR lis_unregister_strmod ()
returns zero (0).
Upon failure,
.BR lis_unregister_strmod ()
returns a negative error number.
.SH ERRORS
.PP
When
.BR lis_unregister_strmod ()
fails, it returns the negative of one of the following errors:
.TP 12
.RB [ EINVAL ]
.I strtab
does not refer to an existing registered
.IR STREAMS (4)
module.
.TP 12
.RB [ EBUSY ]
The
.IR STREAMS (4)
module indicated by
.I strtab
is currently pushed on an open stream.
.SH CAVEATS
.PP
There are some interactions between the
demand
.B Linux
kernel module loading described in
.BR lis_register_strmod (9)
and unloading of the driver.
.B LiS
.[
LiS
.]
does not attempt to unload a kernel module that calls
.BR lis_unregister_strmod .
One reason for this is that
.BR lis_unregister_strmod ()
is normally called during kernel module unloading.  If the kernel module does
not unload, a subsequent attempt to
.B I_PUSH
the module by name will result in a failed attempt to reload the kernel module
\fB\)streams-\fI\)name\fB.o\fR.  (This attempt will fail because the kernel
module is already loaded.)
.PP
Therefore, demand loaded
.B Linux
kernel modules that provide
.B LiS
.[
LiS
.]
.IR STREAMS (4)
modules should only call
.BR lis_register_strmod (9)
from their kernel module intialization routines, and should only call
.BR lis_unregister_strmod (9)
from their kernel module cleanup routines.  See
.IR "\*(lqEXAMPLES\*(rq" ,
below.
.SH EXAMPLES
.PP
Following is an example of a
.IR STREAMS (4)
module which is dynamically registered
and deregistered from the
.B LiS
.[
LiS
.]
.IR STREAMS (4)
subsystem:
.sp
.in +4
.nf
\fC\s-2\
#define X_MOD_NAME "example"

int x_initialized = 0;

void x_init(void)
{
    unless(x_initialized > 0, return);
    if ((x_initialized = lis_register_strmod(&x_info, X_MOD_NAME))
        == LIS_NULL_MID) {
        cmn_err(CE_WARN, "%s: couldn't register module", X_MOD_NAME);
    }
    return;
}
void x_terminate(void)
{
    ensure(x_initialized > 0, return);
    if ((x_initialized = lis_unregister_strmod(&x_info)) < 0) {
        cmn_err(CE_PANIC, "%s: couldn't unregister module", X_MOD_NAME);
    }
    return;
}
\s+2\fR
.fi
.PP
Because of interactions between demand
.B Linux
kernel module loading and unloading and
.B LiS
.[
LiS
.]
.IR STREAMS (4)
module registration and deregistration,
.BR lis_register_strmod "(9) and " lis_unregister_strmod (9)
should only be called from within the kernel module init and cleanup routines
as illustrated below:
.sp
.in +4
.nf
\fC\s-2\
int init_module(void)
{
    x_init();
    if (x_initialized < 0)
        return x_initialized;
    return (0);
}
void cleanup_module(void)
{
    x_terminate();
}
\s+2\fR
.fi
.SH "SEE ALSO"
.PP
.BR lis_register_strdev (9),
.BR lis_register_strmod (9),
.BR lis_unregister_strdev (9).
.SH VERSIONS
.PP
This manpage was written for
.B LiS\c
.
.[
LiS
.]
.PP
.BR lis_unregister_strdev ()
is an LiS-specific function that first appeared in early version of
.BR LiS .
.\"
.\"
.XX
.[
magic
.]
.[
svr42
.]
.[
svr4
.]
.\"
.\"
.[
$LIST$
.]
.TA