unr.9 revision 152755
Copyright (c) 2005 Gleb Smirnoff <glebius@FreeBSD.org>
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$FreeBSD: head/share/man/man9/alloc_unr.9 152755 2005-11-24 09:25:10Z joel $
.Dd March 23, 2005 .Dt ALLOC_UNR 9 .Os .Sh NAME .Nm new_unrhdr , .Nm delete_unrhdr , .Nm alloc_unr , .Nm free_unr .Nd "kernel unit number allocator" .Sh SYNOPSIS n sys/systm.h .Ft "struct unrhdr *" .Fn new_unrhdr "int low" "int high" "struct mtx *mutex" .Ft void .Fn delete_unrhdr "struct unrhdr *uh" .Ft int .Fn alloc_unr "struct unrhdr *uh" .Ft int .Fn alloc_unrl "struct unrhdr *uh" .Ft void .Fn free_unr "struct unrhdr *uh" "u_int item" .Sh DESCRIPTION The kernel unit number allocator is a generic facility, which allows to allocate unit numbers within a specified range. l -tag -width indent t Fn new_unrhdr low high mutex Initialize a new unit number allocator entity. The .Fa low and .Fa high arguments specify minimum and maximum number of unit numbers. There is no cost associated with the range of unit numbers, so unless the resource really is finite, .Dv INT_MAX can be used. If .Fa mutex is not .Dv NULL , it is used for locking when allocating and freeing units. Otherwise, internal mutex is used. t Fn delete_unrhdr uh Destroy specified unit number allocator entity. t Fn alloc_unr uh Return a new unit number. The lowest free number is always allocated. This function does not allocate memory and never sleeps, however it may block on a mutex. If no free unit numbers are left, .Li -1 is returned. t Fn alloc_unrl uh Same as .Fn alloc_unr except that mutex is assumed to be already locked and thus is not used. t Fn free_unr uh Free a previously allocated unit number. This function may require allocating memory, and thus it can sleep. There is no pre-locked variant. .El .Sh CODE REFERENCES The above functions are implemented in
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions
are met:
1. Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.
$FreeBSD: head/share/man/man9/alloc_unr.9 152755 2005-11-24 09:25:10Z joel $
.Dd March 23, 2005 .Dt ALLOC_UNR 9 .Os .Sh NAME .Nm new_unrhdr , .Nm delete_unrhdr , .Nm alloc_unr , .Nm free_unr .Nd "kernel unit number allocator" .Sh SYNOPSIS n sys/systm.h .Ft "struct unrhdr *" .Fn new_unrhdr "int low" "int high" "struct mtx *mutex" .Ft void .Fn delete_unrhdr "struct unrhdr *uh" .Ft int .Fn alloc_unr "struct unrhdr *uh" .Ft int .Fn alloc_unrl "struct unrhdr *uh" .Ft void .Fn free_unr "struct unrhdr *uh" "u_int item" .Sh DESCRIPTION The kernel unit number allocator is a generic facility, which allows to allocate unit numbers within a specified range. l -tag -width indent t Fn new_unrhdr low high mutex Initialize a new unit number allocator entity. The .Fa low and .Fa high arguments specify minimum and maximum number of unit numbers. There is no cost associated with the range of unit numbers, so unless the resource really is finite, .Dv INT_MAX can be used. If .Fa mutex is not .Dv NULL , it is used for locking when allocating and freeing units. Otherwise, internal mutex is used. t Fn delete_unrhdr uh Destroy specified unit number allocator entity. t Fn alloc_unr uh Return a new unit number. The lowest free number is always allocated. This function does not allocate memory and never sleeps, however it may block on a mutex. If no free unit numbers are left, .Li -1 is returned. t Fn alloc_unrl uh Same as .Fn alloc_unr except that mutex is assumed to be already locked and thus is not used. t Fn free_unr uh Free a previously allocated unit number. This function may require allocating memory, and thus it can sleep. There is no pre-locked variant. .El .Sh CODE REFERENCES The above functions are implemented in
a sys/kern/subr_unit.c . .Sh HISTORY Kernel unit number allocator first appeared in .Fx 6.0 . .Sh AUTHORS .An -nosplit Kernel unit number allocator was written by .An Poul-Henning Kamp . This manpage was written by .An Gleb Smirnoff .