'\" t
.\"     Title: fence_add_callback
.\"    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: Device drivers infrastructure
.\"    Source: Kernel Hackers Manual 4.8.15
.\"  Language: English
.\"
.TH "FENCE_ADD_CALLBACK" "9" "January 2017" "Kernel Hackers Manual 4\&.8\&." "Device drivers infrastructure"
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.SH "NAME"
fence_add_callback \- add a callback to be called when the fence is signaled
.SH "SYNOPSIS"
.HP \w'int\ fence_add_callback('u
.BI "int fence_add_callback(struct\ fence\ *\ " "fence" ", struct\ fence_cb\ *\ " "cb" ", fence_func_t\ " "func" ");"
.SH "ARGUMENTS"
.PP
\fIfence\fR
.RS 4
[in] the fence to wait on
.RE
.PP
\fIcb\fR
.RS 4
[in] the callback to register
.RE
.PP
\fIfunc\fR
.RS 4
[in] the function to call
.RE
.SH "DESCRIPTION"
.PP
cb will be initialized by fence_add_callback, no initialization by the caller is required\&. Any number of callbacks can be registered to a fence, but a callback can only be registered to one fence at a time\&.
.PP
Note that the callback can be called from an atomic context\&. If fence is already signaled, this function will return \-ENOENT (and *not* call the callback)
.PP
Add a software callback to the fence\&. Same restrictions apply to refcount as it does to fence_wait, however the caller doesn\*(Aqt need to keep a refcount to fence afterwards: when software access is enabled, the creator of the fence is required to keep the fence alive until after it signals with fence_signal\&. The callback itself can be called from irq context\&.
.SH "COPYRIGHT"
.br