'\" t
.\"     Title: futex_wait_setup
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: June 2017
.\"    Manual: Futex API reference
.\"    Source: Kernel Hackers Manual 4.11.3
.\"  Language: English
.\"
.TH "FUTEX_WAIT_SETUP" "9" "June 2017" "Kernel Hackers Manual 4\&.11\&" "Futex API reference"
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.SH "NAME"
futex_wait_setup \- Prepare to wait on a futex
.SH "SYNOPSIS"
.HP \w'int\ futex_wait_setup('u
.BI "int futex_wait_setup(u32\ __user\ *\ " "uaddr" ", u32\ " "val" ", unsigned\ int\ " "flags" ", struct\ futex_q\ *\ " "q" ", struct\ futex_hash_bucket\ **\ " "hb" ");"
.SH "ARGUMENTS"
.PP
\fIu32 __user * uaddr\fR
.RS 4
the futex userspace address
.RE
.PP
\fIu32 val\fR
.RS 4
the expected value
.RE
.PP
\fIunsigned int flags\fR
.RS 4
futex flags (FLAGS_SHARED, etc\&.)
.RE
.PP
\fIstruct futex_q * q\fR
.RS 4
the associated futex_q
.RE
.PP
\fIstruct futex_hash_bucket ** hb\fR
.RS 4
storage for hash_bucket pointer to be returned to caller
.RE
.SH "DESCRIPTION"
.PP
Setup the futex_q and locate the hash_bucket\&. Get the futex value and compare it with the expected value\&. Handle atomic faults internally\&. Return with the hb lock held and a q\&.key reference on success, and unlocked with no q\&.key reference on failure\&.
.SH "RETURN"
.PP
0 \- uaddr contains val and hb has been locked; <1 \- \-EFAULT or \-EWOULDBLOCK (uaddr does not contain val) and hb is unlocked
.SH "AUTHOR"
.PP
\fBRusty Russell\fR <\&rusty@rustcorp.com.au\&>
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br