'\" t
.\"     Title: idr_preload
.\"    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_PRELOAD" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Basic Kernel Library Functions"
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.SH "NAME"
idr_preload \- preload for \fBidr_alloc\fR
.SH "SYNOPSIS"
.HP \w'void\ idr_preload('u
.BI "void idr_preload(gfp_t\ " "gfp_mask" ");"
.SH "ARGUMENTS"
.PP
\fIgfp_mask\fR
.RS 4
allocation mask to use for preloading
.RE
.SH "DESCRIPTION"
.PP
Preload per\-cpu layer buffer for
\fBidr_alloc\fR\&. Can only be used from process context and each
\fBidr_preload\fR
invocation should be matched with
\fBidr_preload_end\fR\&. Note that preemption is disabled while preloaded\&.
.PP
The first
\fBidr_alloc\fR
in the preloaded section can be treated as if it were invoked with
\fIgfp_mask\fR
used for preloading\&. This allows using more permissive allocation masks for idrs protected by spinlocks\&.
.PP
For example, if
\fBidr_alloc\fR
below fails, the failure can be treated as if
\fBidr_alloc\fR
were called with GFP_KERNEL rather than GFP_NOWAIT\&.
.PP
idr_preload(GFP_KERNEL); spin_lock(lock);
.PP
id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);
.PP
spin_unlock(lock);
\fBidr_preload_end\fR; if (id < 0) error;
.SH "COPYRIGHT"
.br