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Since most dvb ioctls wrap their real work with dvb_usercopy, the static mutex
used in dvb_usercopy effectively is a global lock for dvb ioctls.
Unfortunately, frontend ioctls can be blocked by the frontend thread for
several seconds; this leads to unacceptable lock contention. Mitigate that by
pushing the mutex from dvb_usercopy down to the individual, device specific
ioctls.
There are 10 such ioctl functions using dvb_usercopy, either calling it
directly, or via the trivial wrapper dvb_generic_ioctl. The following already
employ their own locking and look safe:
• dvb_demux_ioctl (as per dvb_demux_do_ioctl)
• dvb_dvr_ioctl (as per dvb_dvr_do_ioctl)
• dvb_osd_ioctl (as per single non-trivial callee)
• fdtv_ca_ioctl (as per callees)
• dvb_frontend_ioctl
The following functions do not, and are thus changed to use a device specific
mutex:
• dvb_net_ioctl (as per dvb_net_do_ioctl)
• dvb_ca_en50221_io_ioctl (as per dvb_ca_en50221_io_do_ioctl)
• dvb_video_ioctl
• dvb_audio_ioctl
• dvb_ca_ioctl
Signed-off-by: Nikolaus Schulz <schulz@macnetix.de>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
68 lines
1.7 KiB
C
68 lines
1.7 KiB
C
/*
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* dvb_net.h
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*
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* Copyright (C) 2001 Ralph Metzler for convergence integrated media GmbH
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public License
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* as published by the Free Software Foundation; either version 2.1
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#ifndef _DVB_NET_H_
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#define _DVB_NET_H_
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#include <linux/module.h>
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#include <linux/netdevice.h>
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#include <linux/inetdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/skbuff.h>
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#include "dvbdev.h"
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#define DVB_NET_DEVICES_MAX 10
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#ifdef CONFIG_DVB_NET
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struct dvb_net {
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struct dvb_device *dvbdev;
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struct net_device *device[DVB_NET_DEVICES_MAX];
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int state[DVB_NET_DEVICES_MAX];
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unsigned int exit:1;
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struct dmx_demux *demux;
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struct mutex ioctl_mutex;
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};
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void dvb_net_release(struct dvb_net *);
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int dvb_net_init(struct dvb_adapter *, struct dvb_net *, struct dmx_demux *);
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#else
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struct dvb_net {
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struct dvb_device *dvbdev;
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};
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static inline void dvb_net_release(struct dvb_net *dvbnet)
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{
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}
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static inline int dvb_net_init(struct dvb_adapter *adap,
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struct dvb_net *dvbnet, struct dmx_demux *dmx)
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{
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return 0;
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}
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#endif /* ifdef CONFIG_DVB_NET */
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#endif
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