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.\"     Title: cond_synchronize_sched
.\"    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: Driver Basics
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "COND_SYNCHRONIZE_SCH" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Driver Basics"
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.SH "NAME"
cond_synchronize_sched \- Conditionally wait for an RCU\-sched grace period
.SH "SYNOPSIS"
.HP \w'void\ cond_synchronize_sched('u
.BI "void cond_synchronize_sched(unsigned\ long\ " "oldstate" ");"
.SH "ARGUMENTS"
.PP
\fIoldstate\fR
.RS 4
return value from earlier call to
\fBget_state_synchronize_sched\fR
.RE
.SH "DESCRIPTION"
.PP
If a full RCU\-sched grace period has elapsed since the earlier call to
\fBget_state_synchronize_sched\fR, just return\&. Otherwise, invoke
\fBsynchronize_sched\fR
to wait for a full grace period\&.
.PP
Yes, this function does not take counter wrap into account\&. But counter wrap is harmless\&. If the counter wraps, we have waited for more than 2 billion grace periods (and way more on a 64\-bit system!), so waiting for one additional grace period should be just fine\&.
.SH "COPYRIGHT"
.br