/*
 * Copyright (c) 1999 Al Smith
 *
 * Portions derived from work (c) 1995,1996 Christian Vogelgsang.
 * Portions derived from IRIX header files (c) 1988 Silicon Graphics
 */
#ifndef _EFS_EFS_H_
#define _EFS_EFS_H_

#ifdef pr_fmt
#undef pr_fmt
#endif

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/fs.h>
#include <linux/uaccess.h>

#define EFS_VERSION "1.0a"

static const char cprt[] = "EFS: "EFS_VERSION" - (c) 1999 Al Smith <Al.Smith@aeschi.ch.eu.org>";


/* 1 block is 512 bytes */
#define	EFS_BLOCKSIZE_BITS	9
#define	EFS_BLOCKSIZE		(1 << EFS_BLOCKSIZE_BITS)

typedef	int32_t		efs_block_t;
typedef uint32_t	efs_ino_t;

#define	EFS_DIRECTEXTENTS	12

/*
 * layout of an extent, in memory and on disk. 8 bytes exactly.
 */
typedef union extent_u {
	unsigned char raw[8];
	struct extent_s {
		unsigned int	ex_magic:8;	/* magic # (zero) */
		unsigned int	ex_bn:24;	/* basic block */
		unsigned int	ex_length:8;	/* numblocks in this extent */
		unsigned int	ex_offset:24;	/* logical offset into file */
	} cooked;
} efs_extent;

typedef struct edevs {
	__be16		odev;
	__be32		ndev;
} efs_devs;

/*
 * extent based filesystem inode as it appears on disk.  The efs inode
 * is exactly 128 bytes long.
 */
struct	efs_dinode {
	__be16		di_mode;	/* mode and type of file */
	__be16		di_nlink;	/* number of links to file */
	__be16		di_uid;		/* owner's user id */
	__be16		di_gid;		/* owner's group id */
	__be32		di_size;	/* number of bytes in file */
	__be32		di_atime;	/* time last accessed */
	__be32		di_mtime;	/* time last modified */
	__be32		di_ctime;	/* time created */
	__be32		di_gen;		/* generation number */
	__be16		di_numextents;	/* # of extents */
	u_char		di_version;	/* version of inode */
	u_char		di_spare;	/* spare - used by AFS */
	union di_addr {
		efs_extent	di_extents[EFS_DIRECTEXTENTS];
		efs_devs	di_dev;	/* device for IFCHR/IFBLK */
	} di_u;
};

/* efs inode storage in memory */
struct efs_inode_info {
	int		numextents;
	int		lastextent;

	efs_extent	extents[EFS_DIRECTEXTENTS];
	struct inode	vfs_inode;
};

#include <linux/efs_fs_sb.h>

#define EFS_DIRBSIZE_BITS	EFS_BLOCKSIZE_BITS
#define EFS_DIRBSIZE		(1 << EFS_DIRBSIZE_BITS)

struct efs_dentry {
	__be32		inode;
	unsigned char	namelen;
	char		name[3];
};

#define EFS_DENTSIZE	(sizeof(struct efs_dentry) - 3 + 1)
#define EFS_MAXNAMELEN  ((1 << (sizeof(char) * 8)) - 1)

#define EFS_DIRBLK_HEADERSIZE	4
#define EFS_DIRBLK_MAGIC	0xbeef	/* moo */

struct efs_dir {
	__be16	magic;
	unsigned char	firstused;
	unsigned char	slots;

	unsigned char	space[EFS_DIRBSIZE - EFS_DIRBLK_HEADERSIZE];
};

#define EFS_MAXENTS \
	((EFS_DIRBSIZE - EFS_DIRBLK_HEADERSIZE) / \
	 (EFS_DENTSIZE + sizeof(char)))

#define EFS_SLOTAT(dir, slot) EFS_REALOFF((dir)->space[slot])

#define EFS_REALOFF(offset) ((offset << 1))


static inline struct efs_inode_info *INODE_INFO(struct inode *inode)
{
	return container_of(inode, struct efs_inode_info, vfs_inode);
}

static inline struct efs_sb_info *SUPER_INFO(struct super_block *sb)
{
	return sb->s_fs_info;
}

struct statfs;
struct fid;

extern const struct inode_operations efs_dir_inode_operations;
extern const struct file_operations efs_dir_operations;
extern const struct address_space_operations efs_symlink_aops;

extern struct inode *efs_iget(struct super_block *, unsigned long);
extern efs_block_t efs_map_block(struct inode *, efs_block_t);
extern int efs_get_block(struct inode *, sector_t, struct buffer_head *, int);

extern struct dentry *efs_lookup(struct inode *, struct dentry *, unsigned int);
extern struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid,
		int fh_len, int fh_type);
extern struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid,
		int fh_len, int fh_type);
extern struct dentry *efs_get_parent(struct dentry *);
extern int efs_bmap(struct inode *, int);

#endif /* _EFS_EFS_H_ */
'>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/include/net/sctp/auth.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>39cb2c9a316e77f6dfba96c543e55b6672d5a37e</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/net/sctp/auth.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/include/net/sctp/auth.h?id=39cb2c9a316e77f6dfba96c543e55b6672d5a37e'>include/net/sctp/auth.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/net/sctp/auth.h?id=2c5d9555d6d937966d79d4c6529a5f7b9206e405'>2c5d9555d6d937966d79d4c6529a5f7b9206e405</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/net/sctp/auth.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 'include/net/sctp/auth.h')</div><table summary='diffstat' class='diffstat'>