/*
   Copyright (c) 2010,2011 Code Aurora Forum.  All rights reserved.
   Copyright (c) 2011,2012 Intel Corp.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License version 2 and
   only version 2 as published by the Free Software Foundation.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
*/

#ifndef __A2MP_H
#define __A2MP_H

#include <net/bluetooth/l2cap.h>

enum amp_mgr_state {
	READ_LOC_AMP_INFO,
	READ_LOC_AMP_ASSOC,
	READ_LOC_AMP_ASSOC_FINAL,
	WRITE_REMOTE_AMP_ASSOC,
};

struct amp_mgr {
	struct list_head	list;
	struct l2cap_conn	*l2cap_conn;
	struct l2cap_chan	*a2mp_chan;
	struct l2cap_chan	*bredr_chan;
	struct kref		kref;
	__u8			ident;
	__u8			handle;
	unsigned long		state;
	unsigned long		flags;

	struct list_head	amp_ctrls;
	struct mutex		amp_ctrls_lock;
};

struct a2mp_cmd {
	__u8	code;
	__u8	ident;
	__le16	len;
	__u8	data[0];
} __packed;

/* A2MP command codes */
#define A2MP_COMMAND_REJ         0x01
struct a2mp_cmd_rej {
	__le16	reason;
	__u8	data[0];
} __packed;

#define A2MP_DISCOVER_REQ        0x02
struct a2mp_discov_req {
	__le16	mtu;
	__le16	ext_feat;
} __packed;

struct a2mp_cl {
	__u8	id;
	__u8	type;
	__u8	status;
} __packed;

#define A2MP_DISCOVER_RSP        0x03
struct a2mp_discov_rsp {
	__le16     mtu;
	__le16     ext_feat;
	struct a2mp_cl cl[0];
} __packed;

#define A2MP_CHANGE_NOTIFY       0x04
#define A2MP_CHANGE_RSP          0x05

#define A2MP_GETINFO_REQ         0x06
struct a2mp_info_req {
	__u8       id;
} __packed;

#define A2MP_GETINFO_RSP         0x07
struct a2mp_info_rsp {
	__u8	id;
	__u8	status;
	__le32	total_bw;
	__le32	max_bw;
	__le32	min_latency;
	__le16	pal_cap;
	__le16	assoc_size;
} __packed;

#define A2MP_GETAMPASSOC_REQ     0x08
struct a2mp_amp_assoc_req {
	__u8	id;
} __packed;

#define A2MP_GETAMPASSOC_RSP     0x09
struct a2mp_amp_assoc_rsp {
	__u8	id;
	__u8	status;
	__u8	amp_assoc[0];
} __packed;

#define A2MP_CREATEPHYSLINK_REQ  0x0A
#define A2MP_DISCONNPHYSLINK_REQ 0x0C
struct a2mp_physlink_req {
	__u8	local_id;
	__u8	remote_id;
	__u8	amp_assoc[0];
} __packed;

#define A2MP_CREATEPHYSLINK_RSP  0x0B
#define A2MP_DISCONNPHYSLINK_RSP 0x0D
struct a2mp_physlink_rsp {
	__u8	local_id;
	__u8	remote_id;
	__u8	status;
} __packed;

/* A2MP response status */
#define A2MP_STATUS_SUCCESS			0x00
#define A2MP_STATUS_INVALID_CTRL_ID		0x01
#define A2MP_STATUS_UNABLE_START_LINK_CREATION	0x02
#define A2MP_STATUS_NO_PHYSICAL_LINK_EXISTS	0x02
#define A2MP_STATUS_COLLISION_OCCURED		0x03
#define A2MP_STATUS_DISCONN_REQ_RECVD		0x04
#define A2MP_STATUS_PHYS_LINK_EXISTS		0x05
#define A2MP_STATUS_SECURITY_VIOLATION		0x06

struct amp_mgr *amp_mgr_get(struct amp_mgr *mgr);

#if IS_ENABLED(CONFIG_BT_HS)
int amp_mgr_put(struct amp_mgr *mgr);
struct l2cap_chan *a2mp_channel_create(struct l2cap_conn *conn,
				       struct sk_buff *skb);
void a2mp_discover_amp(struct l2cap_chan *chan);
#else
static inline int amp_mgr_put(struct amp_mgr *mgr)
{
	return 0;
}

static inline struct l2cap_chan *a2mp_channel_create(struct l2cap_conn *conn,
						     struct sk_buff *skb)
{
	return NULL;
}

static inline void a2mp_discover_amp(struct l2cap_chan *chan)
{
}
#endif

void a2mp_send_getinfo_rsp(struct hci_dev *hdev);
void a2mp_send_getampassoc_rsp(struct hci_dev *hdev, u8 status);
void a2mp_send_create_phy_link_req(struct hci_dev *hdev, u8 status);
void a2mp_send_create_phy_link_rsp(struct hci_dev *hdev, u8 status);

#endif /* __A2MP_H */
lected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>committer</th><td>Linus Torvalds &lt;torvalds@linux-foundation.org&gt;</td><td class='right'>2017-01-29 13:50:06 -0800</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/mtu3/mtu3_dr.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/mtu3/mtu3_dr.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>98fe974ee4e20121253de7f61fc8d01bdb3821c1</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/mtu3/mtu3_dr.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>drivers/usb/mtu3/mtu3_dr.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/mtu3/mtu3_dr.h?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/mtu3/mtu3_dr.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e&amp;id2=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>diff</a>)</td></tr></table>
<div class='commit-subject'>drm/i915: Check for NULL i915_vma in intel_unpin_fb_obj()</div><div class='commit-msg'>I've seen this trigger twice now, where the i915_gem_object_to_ggtt()
call in intel_unpin_fb_obj() returns NULL, resulting in an oops
immediately afterwards as the (inlined) call to i915_vma_unpin_fence()
tries to dereference it.

It seems to be some race condition where the object is going away at
shutdown time, since both times happened when shutting down the X
server.  The call chains were different:

 - VT ioctl(KDSETMODE, KD_TEXT):

    intel_cleanup_plane_fb+0x5b/0xa0 [i915]
    drm_atomic_helper_cleanup_planes+0x6f/0x90 [drm_kms_helper]
    intel_atomic_commit_tail+0x749/0xfe0 [i915]
    intel_atomic_commit+0x3cb/0x4f0 [i915]
    drm_atomic_commit+0x4b/0x50 [drm]
    restore_fbdev_mode+0x14c/0x2a0 [drm_kms_helper]
    drm_fb_helper_restore_fbdev_mode_unlocked+0x34/0x80 [drm_kms_helper]
    drm_fb_helper_set_par+0x2d/0x60 [drm_kms_helper]
    intel_fbdev_set_par+0x18/0x70 [i915]
    fb_set_var+0x236/0x460
    fbcon_blank+0x30f/0x350
    do_unblank_screen+0xd2/0x1a0
    vt_ioctl+0x507/0x12a0
    tty_ioctl+0x355/0xc30
    do_vfs_ioctl+0xa3/0x5e0
    SyS_ioctl+0x79/0x90
    entry_SYSCALL_64_fastpath+0x13/0x94

 - i915 unpin_work workqueue:

    intel_unpin_work_fn+0x58/0x140 [i915]
    process_one_work+0x1f1/0x480
    worker_thread+0x48/0x4d0
    kthread+0x101/0x140

and this patch purely papers over the issue by adding a NULL pointer
check and a WARN_ON_ONCE() to avoid the oops that would then generally
make the machine unresponsive.

Other callers of i915_gem_object_to_ggtt() seem to also check for the
returned pointer being NULL and warn about it, so this clearly has
happened before in other places.

[ Reported it originally to the i915 developers on Jan 8, applying the
  ugly workaround on my own now after triggering the problem for the
  second time with no feedback.

  This is likely to be the same bug reported as

     https://bugs.freedesktop.org/show_bug.cgi?id=98829
     https://bugs.freedesktop.org/show_bug.cgi?id=99134

  which has a patch for the underlying problem, but it hasn't gotten to
  me, so I'm applying the workaround. ]

Cc: Daniel Vetter &lt;daniel.vetter@intel.com&gt;
Cc: Jani Nikula &lt;jani.nikula@linux.intel.com&gt;
Cc: Ville Syrjälä &lt;ville.syrjala@linux.intel.com&gt;
Cc: Chris Wilson &lt;chris@chris-wilson.co.uk&gt;
Cc: Maarten Lankhorst &lt;maarten.lankhorst@linux.intel.com&gt;
Cc: Tvrtko Ursulin &lt;tvrtko.ursulin@intel.com&gt;
Cc: Imre Deak &lt;imre.deak@intel.com&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>Diffstat</a> (limited to 'drivers/usb/mtu3/mtu3_dr.h')</div><table summary='diffstat' class='diffstat'>