'\" t
.\"     Title: idr_alloc
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: January 2017
.\"    Manual: Basic Kernel Library Functions
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "IDR_ALLOC" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Basic Kernel Library Functions"
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.SH "NAME"
idr_alloc \- allocate new idr entry
.SH "SYNOPSIS"
.HP \w'int\ idr_alloc('u
.BI "int idr_alloc(struct\ idr\ *\ " "idr" ", void\ *\ " "ptr" ", int\ " "start" ", int\ " "end" ", gfp_t\ " "gfp_mask" ");"
.SH "ARGUMENTS"
.PP
\fIidr\fR
.RS 4
the (initialized) idr
.RE
.PP
\fIptr\fR
.RS 4
pointer to be associated with the new id
.RE
.PP
\fIstart\fR
.RS 4
the minimum id (inclusive)
.RE
.PP
\fIend\fR
.RS 4
the maximum id (exclusive, <= 0 for max)
.RE
.PP
\fIgfp_mask\fR
.RS 4
memory allocation flags
.RE
.SH "DESCRIPTION"
.PP
Allocate an id in [start, end) and associate it with
\fIptr\fR\&. If no ID is available in the specified range, returns \-ENOSPC\&. On memory allocation failure, returns \-ENOMEM\&.
.PP
Note that
\fIend\fR
is treated as max when <= 0\&. This is to always allow using
\fIstart\fR
+ N as
\fIend\fR
as long as N is inside integer range\&.
.PP
The user is responsible for exclusively synchronizing all operations which may modify
\fIidr\fR\&. However, read\-only accesses such as
\fBidr_find\fR
or iteration can be performed under RCU read lock provided the user destroys
\fIptr\fR
in RCU\-safe way after removal from idr\&.
.SH "COPYRIGHT"
.br