'\" t
.\"     Title: usb_hcd_check_unlink_urb
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.78.1 <http://docbook.sf.net/>
.\"      Date: May 2018
.\"    Manual: Host Controller APIs
.\"    Source: Kernel Hackers Manual 3.16.56
.\"  Language: English
.\"
.TH "USB_HCD_CHECK_UNLINK" "9" "May 2018" "Kernel Hackers Manual 3\&.16\&" "Host Controller APIs"
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.SH "NAME"
usb_hcd_check_unlink_urb \- check whether an URB may be unlinked
.SH "SYNOPSIS"
.HP \w'int\ usb_hcd_check_unlink_urb('u
.BI "int usb_hcd_check_unlink_urb(struct\ usb_hcd\ *\ " "hcd" ", struct\ urb\ *\ " "urb" ", int\ " "status" ");"
.SH "ARGUMENTS"
.PP
\fIhcd\fR
.RS 4
host controller to which
\fIurb\fR
was submitted
.RE
.PP
\fIurb\fR
.RS 4
URB being checked for unlinkability
.RE
.PP
\fIstatus\fR
.RS 4
error code to store in
\fIurb\fR
if the unlink succeeds
.RE
.SH "DESCRIPTION"
.PP
Host controller drivers should call this routine in their
\fBdequeue\fR
method\&. The HCD\*(Aqs private spinlock must be held and interrupts must be disabled\&. The actions carried out here are required for making sure than an unlink is valid\&.
.SH "RETURN"
.PP
0 for no error, otherwise a negative error code (in which case the
\fBdequeue\fR
method must fail)\&. The possible error codes are:
.PP
\-EIDRM:
\fIurb\fR
was not submitted or has already completed\&. The completion function may not have been called yet\&.
.PP
\-EBUSY:
\fIurb\fR
has already been unlinked\&.
.SH "COPYRIGHT"
.br