/*
 *  SCSI Transport Netlink Interface
 *    Used for the posting of outbound SCSI transport events
 *
 *  Copyright (C) 2006   James Smart, Emulex Corporation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */
#ifndef SCSI_NETLINK_H
#define SCSI_NETLINK_H

#include <linux/netlink.h>
#include <linux/types.h>

/*
 * This file intended to be included by both kernel and user space
 */

/* Single Netlink Message type to send all SCSI Transport messages */
#define SCSI_TRANSPORT_MSG		NLMSG_MIN_TYPE + 1

/* SCSI Transport Broadcast Groups */
	/* leaving groups 0 and 1 unassigned */
#define SCSI_NL_GRP_FC_EVENTS		(1<<2)		/* Group 2 */
#define SCSI_NL_GRP_CNT			3


/* SCSI_TRANSPORT_MSG event message header */
struct scsi_nl_hdr {
	uint8_t version;
	uint8_t transport;
	uint16_t magic;
	uint16_t msgtype;
	uint16_t msglen;
} __attribute__((aligned(sizeof(uint64_t))));

/* scsi_nl_hdr->version value */
#define SCSI_NL_VERSION				1

/* scsi_nl_hdr->magic value */
#define SCSI_NL_MAGIC				0xA1B2

/* scsi_nl_hdr->transport value */
#define SCSI_NL_TRANSPORT			0
#define SCSI_NL_TRANSPORT_FC			1
#define SCSI_NL_MAX_TRANSPORTS			2

/* Transport-based scsi_nl_hdr->msgtype values are defined in each transport */

/*
 * GENERIC SCSI scsi_nl_hdr->msgtype Values
 */
	/* kernel -> user */
#define SCSI_NL_SHOST_VENDOR			0x0001
	/* user -> kernel */
/* SCSI_NL_SHOST_VENDOR msgtype is kernel->user and user->kernel */


/*
 * Message Structures :
 */

/* macro to round up message lengths to 8byte boundary */
#define SCSI_NL_MSGALIGN(len)		(((len) + 7) & ~7)


/*
 * SCSI HOST Vendor Unique messages :
 *   SCSI_NL_SHOST_VENDOR
 *
 * Note: The Vendor Unique message payload will begin directly after
 * 	 this structure, with the length of the payload per vmsg_datalen.
 *
 * Note: When specifying vendor_id, be sure to read the Vendor Type and ID
 *   formatting requirements specified below
 */
struct scsi_nl_host_vendor_msg {
	struct scsi_nl_hdr snlh;		/* must be 1st element ! */
	uint64_t vendor_id;
	uint16_t host_no;
	uint16_t vmsg_datalen;
} __attribute__((aligned(sizeof(uint64_t))));


/*
 * Vendor ID:
 *   If transports post vendor-unique events, they must pass a well-known
 *   32-bit vendor identifier. This identifier consists of 8 bits indicating
 *   the "type" of identifier contained, and 24 bits of id data.
 *
 *   Identifiers for each type:
 *    PCI :  ID data is the 16 bit PCI Registered Vendor ID
 */
#define SCSI_NL_VID_TYPE_SHIFT		56
#define SCSI_NL_VID_TYPE_MASK		((__u64)0xFF << SCSI_NL_VID_TYPE_SHIFT)
#define SCSI_NL_VID_TYPE_PCI		((__u64)0x01 << SCSI_NL_VID_TYPE_SHIFT)
#define SCSI_NL_VID_ID_MASK		(~ SCSI_NL_VID_TYPE_MASK)


#define INIT_SCSI_NL_HDR(hdr, t, mtype, mlen)			\
	{							\
	(hdr)->version = SCSI_NL_VERSION;			\
	(hdr)->transport = t;					\
	(hdr)->magic = SCSI_NL_MAGIC;				\
	(hdr)->msgtype = mtype;					\
	(hdr)->msglen = mlen;					\
	}

#endif /* SCSI_NETLINK_H */

ption value='1'>1</option><option value='2'>2</option><option value='3' selected='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/serial/spcp8x5.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/serial/spcp8x5.c?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/serial/spcp8x5.c?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>drivers/usb/serial/spcp8x5.c</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/serial/spcp8x5.c?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/serial/spcp8x5.c?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/serial/spcp8x5.c')</div><table summary='diffstat' class='diffstat'>