Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

3 files changed, 2943 insertions, 0 deletions

diff --git a/fs/devfs/Makefile b/fs/devfs/Makefile
new file mode 100644
index 00000000000..6dd8d1245e2
--- /dev/null
+++ b/fs/devfs/Makefile
@@ -0,0 +1,8 @@
+#
+# Makefile for the linux devfs-filesystem routines.
+#
+
+obj-$(CONFIG_DEVFS_FS) += devfs.o
+
+devfs-objs := base.o util.o
+
diff --git a/fs/devfs/base.c b/fs/devfs/base.c
new file mode 100644
index 00000000000..1ecfe1f184d
--- /dev/null
+++ b/fs/devfs/base.c
@@ -0,0 +1,2838 @@
+/*  devfs (Device FileSystem) driver.
+
+    Copyright (C) 1998-2002  Richard Gooch
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 of the License, or (at your option) any later version.
+
+    This library 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
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+    Richard Gooch may be reached by email at  rgooch@atnf.csiro.au
+    The postal address is:
+      Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia.
+
+    ChangeLog
+
+    19980110   Richard Gooch <rgooch@atnf.csiro.au>
+               Original version.
+  v0.1
+    19980111   Richard Gooch <rgooch@atnf.csiro.au>
+               Created per-fs inode table rather than using inode->u.generic_ip
+  v0.2
+    19980111   Richard Gooch <rgooch@atnf.csiro.au>
+               Created .epoch inode which has a ctime of 0.
+	       Fixed loss of named pipes when dentries lost.
+	       Fixed loss of inode data when devfs_register() follows mknod().
+  v0.3
+    19980111   Richard Gooch <rgooch@atnf.csiro.au>
+               Fix for when compiling with CONFIG_KERNELD.
+    19980112   Richard Gooch <rgooch@atnf.csiro.au>
+               Fix for readdir() which sometimes didn't show entries.
+	       Added <<tolerant>> option to <devfs_register>.
+  v0.4
+    19980113   Richard Gooch <rgooch@atnf.csiro.au>
+               Created <devfs_fill_file> function.
+  v0.5
+    19980115   Richard Gooch <rgooch@atnf.csiro.au>
+               Added subdirectory support. Major restructuring.
+    19980116   Richard Gooch <rgooch@atnf.csiro.au>
+               Fixed <find_by_dev> to not search major=0,minor=0.
+	       Added symlink support.
+  v0.6
+    19980120   Richard Gooch <rgooch@atnf.csiro.au>
+               Created <devfs_mk_dir> function and support directory unregister
+    19980120   Richard Gooch <rgooch@atnf.csiro.au>
+               Auto-ownership uses real uid/gid rather than effective uid/gid.
+  v0.7
+    19980121   Richard Gooch <rgooch@atnf.csiro.au>
+               Supported creation of sockets.
+  v0.8
+    19980122   Richard Gooch <rgooch@atnf.csiro.au>
+               Added DEVFS_FL_HIDE_UNREG flag.
+	       Interface change to <devfs_mk_symlink>.
+               Created <devfs_symlink> to support symlink(2).
+  v0.9
+    19980123   Richard Gooch <rgooch@atnf.csiro.au>
+               Added check to <devfs_fill_file> to check inode is in devfs.
+	       Added optional traversal of symlinks.
+  v0.10
+    19980124   Richard Gooch <rgooch@atnf.csiro.au>
+               Created <devfs_get_flags> and <devfs_set_flags>.
+  v0.11
+    19980125   C. Scott Ananian <cananian@alumni.princeton.edu>
+               Created <devfs_find_handle>.
+    19980125   Richard Gooch <rgooch@atnf.csiro.au>
+               Allow removal of symlinks.
+  v0.12
+    19980125   Richard Gooch <rgooch@atnf.csiro.au>
+               Created <devfs_set_symlink_destination>.
+    19980126   Richard Gooch <rgooch@atnf.csiro.au>
+               Moved DEVFS_SUPER_MAGIC into header file.
+	       Added DEVFS_FL_HIDE flag.
+	       Created <devfs_get_maj_min>.
+	       Created <devfs_get_handle_from_inode>.
+	       Fixed minor bug in <find_by_dev>.
+    19980127   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed interface to <find_by_dev>, <find_entry>,
+	       <devfs_unregister>, <devfs_fill_file> and <devfs_find_handle>.
+	       Fixed inode times when symlink created with symlink(2).
+  v0.13
+    19980129   C. Scott Ananian <cananian@alumni.princeton.edu>
+               Exported <devfs_set_symlink_destination>, <devfs_get_maj_min>
+	       and <devfs_get_handle_from_inode>.
+    19980129   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_unlink> to support unlink(2).
+  v0.14
+    19980129   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed kerneld support for entries in devfs subdirectories.
+    19980130   Richard Gooch <rgooch@atnf.csiro.au>
+	       Bugfixes in <call_kerneld>.
+  v0.15
+    19980207   Richard Gooch <rgooch@atnf.csiro.au>
+	       Call kerneld when looking up unregistered entries.
+  v0.16
+    19980326   Richard Gooch <rgooch@atnf.csiro.au>
+	       Modified interface to <devfs_find_handle> for symlink traversal.
+  v0.17
+    19980331   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed persistence bug with device numbers for manually created
+	       device files.
+	       Fixed problem with recreating symlinks with different content.
+  v0.18
+    19980401   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed to CONFIG_KMOD.
+	       Hide entries which are manually unlinked.
+	       Always invalidate devfs dentry cache when registering entries.
+	       Created <devfs_rmdir> to support rmdir(2).
+	       Ensure directories created by <devfs_mk_dir> are visible.
+  v0.19
+    19980402   Richard Gooch <rgooch@atnf.csiro.au>
+	       Invalidate devfs dentry cache when making directories.
+	       Invalidate devfs dentry cache when removing entries.
+	       Fixed persistence bug with fifos.
+  v0.20
+    19980421   Richard Gooch <rgooch@atnf.csiro.au>
+	       Print process command when debugging kerneld/kmod.
+	       Added debugging for register/unregister/change operations.
+    19980422   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added "devfs=" boot options.
+  v0.21
+    19980426   Richard Gooch <rgooch@atnf.csiro.au>
+	       No longer lock/unlock superblock in <devfs_put_super>.
+	       Drop negative dentries when they are released.
+	       Manage dcache more efficiently.
+  v0.22
+    19980427   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added DEVFS_FL_AUTO_DEVNUM flag.
+  v0.23
+    19980430   Richard Gooch <rgooch@atnf.csiro.au>
+	       No longer set unnecessary methods.
+  v0.24
+    19980504   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added PID display to <call_kerneld> debugging message.
+	       Added "after" debugging message to <call_kerneld>.
+    19980519   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added "diread" and "diwrite" boot options.
+    19980520   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed persistence problem with permissions.
+  v0.25
+    19980602   Richard Gooch <rgooch@atnf.csiro.au>
+	       Support legacy device nodes.
+	       Fixed bug where recreated inodes were hidden.
+  v0.26
+    19980602   Richard Gooch <rgooch@atnf.csiro.au>
+	       Improved debugging in <get_vfs_inode>.
+    19980607   Richard Gooch <rgooch@atnf.csiro.au>
+	       No longer free old dentries in <devfs_mk_dir>.
+	       Free all dentries for a given entry when deleting inodes.
+  v0.27
+    19980627   Richard Gooch <rgooch@atnf.csiro.au>
+	       Limit auto-device numbering to majors 128 to 239.
+  v0.28
+    19980629   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed inode times persistence problem.
+  v0.29
+    19980704   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed spelling in <devfs_readlink> debug.
+	       Fixed bug in <devfs_setup> parsing "dilookup".
+  v0.30
+    19980705   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed devfs inode leak when manually recreating inodes.
+	       Fixed permission persistence problem when recreating inodes.
+  v0.31
+    19980727   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed harmless "unused variable" compiler warning.
+	       Fixed modes for manually recreated device nodes.
+  v0.32
+    19980728   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added NULL devfs inode warning in <devfs_read_inode>.
+	       Force all inode nlink values to 1.
+  v0.33
+    19980730   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added "dimknod" boot option.
+	       Set inode nlink to 0 when freeing dentries.
+	       Fixed modes for manually recreated symlinks.
+  v0.34
+    19980802   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bugs in recreated directories and symlinks.
+  v0.35
+    19980806   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bugs in recreated device nodes.
+    19980807   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bug in currently unused <devfs_get_handle_from_inode>.
+	       Defined new <devfs_handle_t> type.
+	       Improved debugging when getting entries.
+	       Fixed bug where directories could be emptied.
+  v0.36
+    19980809   Richard Gooch <rgooch@atnf.csiro.au>
+	       Replaced dummy .epoch inode with .devfsd character device.
+    19980810   Richard Gooch <rgooch@atnf.csiro.au>
+	       Implemented devfsd protocol revision 0.
+  v0.37
+    19980819   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added soothing message to warning in <devfs_d_iput>.
+  v0.38
+    19980829   Richard Gooch <rgooch@atnf.csiro.au>
+	       Use GCC extensions for structure initialisations.
+	       Implemented async open notification.
+	       Incremented devfsd protocol revision to 1.
+  v0.39
+    19980908   Richard Gooch <rgooch@atnf.csiro.au>
+	       Moved async open notification to end of <devfs_open>.
+  v0.40
+    19980910   Richard Gooch <rgooch@atnf.csiro.au>
+	       Prepended "/dev/" to module load request.
+	       Renamed <call_kerneld> to <call_kmod>.
+  v0.41
+    19980910   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed typo "AYSNC" -> "ASYNC".
+  v0.42
+    19980910   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added open flag for files.
+  v0.43
+    19980927   Richard Gooch <rgooch@atnf.csiro.au>
+	       Set i_blocks=0 and i_blksize=1024 in <devfs_read_inode>.
+  v0.44
+    19981005   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added test for empty <<name>> in <devfs_find_handle>.
+	       Renamed <generate_path> to <devfs_generate_path> and published.
+  v0.45
+    19981006   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_get_fops>.
+  v0.46
+    19981007   Richard Gooch <rgooch@atnf.csiro.au>
+	       Limit auto-device numbering to majors 144 to 239.
+  v0.47
+    19981010   Richard Gooch <rgooch@atnf.csiro.au>
+	       Updated <devfs_follow_link> for VFS change in 2.1.125.
+  v0.48
+    19981022   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created DEVFS_ FL_COMPAT flag.
+  v0.49
+    19981023   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created "nocompat" boot option.
+  v0.50
+    19981025   Richard Gooch <rgooch@atnf.csiro.au>
+	       Replaced "mount" boot option with "nomount".
+  v0.51
+    19981110   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created "only" boot option.
+  v0.52
+    19981112   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added DEVFS_FL_REMOVABLE flag.
+  v0.53
+    19981114   Richard Gooch <rgooch@atnf.csiro.au>
+	       Only call <scan_dir_for_removable> on first call to
+	       <devfs_readdir>.
+  v0.54
+    19981205   Richard Gooch <rgooch@atnf.csiro.au>
+	       Updated <devfs_rmdir> for VFS change in 2.1.131.
+  v0.55
+    19981218   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_mk_compat>.
+    19981220   Richard Gooch <rgooch@atnf.csiro.au>
+	       Check for partitions on removable media in <devfs_lookup>.
+  v0.56
+    19990118   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added support for registering regular files.
+	       Created <devfs_set_file_size>.
+	       Update devfs inodes from entries if not changed through FS.
+  v0.57
+    19990124   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed <devfs_fill_file> to only initialise temporary inodes.
+	       Trap for NULL fops in <devfs_register>.
+	       Return -ENODEV in <devfs_fill_file> for non-driver inodes.
+  v0.58
+    19990126   Richard Gooch <rgooch@atnf.csiro.au>
+	       Switched from PATH_MAX to DEVFS_PATHLEN.
+  v0.59
+    19990127   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created "nottycompat" boot option.
+  v0.60
+    19990318   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed <devfsd_read> to not overrun event buffer.
+  v0.61
+    19990329   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_auto_unregister>.
+  v0.62
+    19990330   Richard Gooch <rgooch@atnf.csiro.au>
+	       Don't return unregistred entries in <devfs_find_handle>.
+	       Panic in <devfs_unregister> if entry unregistered.
+    19990401   Richard Gooch <rgooch@atnf.csiro.au>
+	       Don't panic in <devfs_auto_unregister> for duplicates.
+  v0.63
+    19990402   Richard Gooch <rgooch@atnf.csiro.au>
+	       Don't unregister already unregistered entries in <unregister>.
+  v0.64
+    19990510   Richard Gooch <rgooch@atnf.csiro.au>
+	       Disable warning messages when unable to read partition table for
+	       removable media.
+  v0.65
+    19990512   Richard Gooch <rgooch@atnf.csiro.au>
+	       Updated <devfs_lookup> for VFS change in 2.3.1-pre1.
+	       Created "oops-on-panic" boot option.
+	       Improved debugging in <devfs_register> and <devfs_unregister>.
+  v0.66
+    19990519   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added documentation for some functions.
+    19990525   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed "oops-on-panic" boot option: now always Oops.
+  v0.67
+    19990531   Richard Gooch <rgooch@atnf.csiro.au>
+	       Improved debugging in <devfs_register>.
+  v0.68
+    19990604   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added "diunlink" and "nokmod" boot options.
+	       Removed superfluous warning message in <devfs_d_iput>.
+  v0.69
+    19990611   Richard Gooch <rgooch@atnf.csiro.au>
+	       Took account of change to <d_alloc_root>.
+  v0.70
+    19990614   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created separate event queue for each mounted devfs.
+	       Removed <devfs_invalidate_dcache>.
+	       Created new ioctl()s.
+	       Incremented devfsd protocol revision to 3.
+	       Fixed bug when re-creating directories: contents were lost.
+	       Block access to inodes until devfsd updates permissions.
+    19990615   Richard Gooch <rgooch@atnf.csiro.au>
+	       Support 2.2.x kernels.
+  v0.71
+    19990623   Richard Gooch <rgooch@atnf.csiro.au>
+	       Switched to sending process uid/gid to devfsd.
+	       Renamed <call_kmod> to <try_modload>.
+	       Added DEVFSD_NOTIFY_LOOKUP event.
+    19990624   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added DEVFSD_NOTIFY_CHANGE event.
+	       Incremented devfsd protocol revision to 4.
+  v0.72
+    19990713   Richard Gooch <rgooch@atnf.csiro.au>
+	       Return EISDIR rather than EINVAL for read(2) on directories.
+  v0.73
+    19990809   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed <devfs_setup> to new __init scheme.
+  v0.74
+    19990901   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed remaining function declarations to new __init scheme.
+  v0.75
+    19991013   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_get_info>, <devfs_set_info>,
+	       <devfs_get_first_child> and <devfs_get_next_sibling>.
+	       Added <<dir>> parameter to <devfs_register>, <devfs_mk_compat>,
+	       <devfs_mk_dir> and <devfs_find_handle>.
+	       Work sponsored by SGI.
+  v0.76
+    19991017   Richard Gooch <rgooch@atnf.csiro.au>
+	       Allow multiple unregistrations.
+	       Work sponsored by SGI.
+  v0.77
+    19991026   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added major and minor number to devfsd protocol.
+	       Incremented devfsd protocol revision to 5.
+	       Work sponsored by SGI.
+  v0.78
+    19991030   Richard Gooch <rgooch@atnf.csiro.au>
+	       Support info pointer for all devfs entry types.
+	       Added <<info>> parameter to <devfs_mk_dir> and
+	       <devfs_mk_symlink>.
+	       Work sponsored by SGI.
+  v0.79
+    19991031   Richard Gooch <rgooch@atnf.csiro.au>
+	       Support "../" when searching devfs namespace.
+	       Work sponsored by SGI.
+  v0.80
+    19991101   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_get_unregister_slave>.
+	       Work sponsored by SGI.
+  v0.81
+    19991103   Richard Gooch <rgooch@atnf.csiro.au>
+	       Exported <devfs_get_parent>.
+	       Work sponsored by SGI.
+  v0.82
+    19991104   Richard Gooch <rgooch@atnf.csiro.au>
+               Removed unused <devfs_set_symlink_destination>.
+    19991105   Richard Gooch <rgooch@atnf.csiro.au>
+               Do not hide entries from devfsd or children.
+	       Removed DEVFS_ FL_TTY_COMPAT flag.
+	       Removed "nottycompat" boot option.
+	       Removed <devfs_mk_compat>.
+	       Work sponsored by SGI.
+  v0.83
+    19991107   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added DEVFS_FL_WAIT flag.
+	       Work sponsored by SGI.
+  v0.84
+    19991107   Richard Gooch <rgooch@atnf.csiro.au>
+	       Support new "disc" naming scheme in <get_removable_partition>.
+	       Allow NULL fops in <devfs_register>.
+	       Work sponsored by SGI.
+  v0.85
+    19991110   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fall back to major table if NULL fops given to <devfs_register>.
+	       Work sponsored by SGI.
+  v0.86
+    19991204   Richard Gooch <rgooch@atnf.csiro.au>
+	       Support fifos when unregistering.
+	       Work sponsored by SGI.
+  v0.87
+    19991209   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed obsolete DEVFS_ FL_COMPAT and DEVFS_ FL_TOLERANT flags.
+	       Work sponsored by SGI.
+  v0.88
+    19991214   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed kmod support.
+	       Work sponsored by SGI.
+  v0.89
+    19991216   Richard Gooch <rgooch@atnf.csiro.au>
+	       Improved debugging in <get_vfs_inode>.
+	       Ensure dentries created by devfsd will be cleaned up.
+	       Work sponsored by SGI.
+  v0.90
+    19991223   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_get_name>.
+	       Work sponsored by SGI.
+  v0.91
+    20000203   Richard Gooch <rgooch@atnf.csiro.au>
+	       Ported to kernel 2.3.42.
+	       Removed <devfs_fill_file>.
+	       Work sponsored by SGI.
+  v0.92
+    20000306   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added DEVFS_ FL_NO_PERSISTENCE flag.
+	       Removed unnecessary call to <update_devfs_inode_from_entry> in
+	       <devfs_readdir>.
+	       Work sponsored by SGI.
+  v0.93
+    20000413   Richard Gooch <rgooch@atnf.csiro.au>
+	       Set inode->i_size to correct size for symlinks.
+    20000414   Richard Gooch <rgooch@atnf.csiro.au>
+	       Only give lookup() method to directories to comply with new VFS
+	       assumptions.
+	       Work sponsored by SGI.
+    20000415   Richard Gooch <rgooch@atnf.csiro.au>
+	       Remove unnecessary tests in symlink methods.
+	       Don't kill existing block ops in <devfs_read_inode>.
+	       Work sponsored by SGI.
+  v0.94
+    20000424   Richard Gooch <rgooch@atnf.csiro.au>
+	       Don't create missing directories in <devfs_find_handle>.
+	       Work sponsored by SGI.
+  v0.95
+    20000430   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added CONFIG_DEVFS_MOUNT.
+	       Work sponsored by SGI.
+  v0.96
+    20000608   Richard Gooch <rgooch@atnf.csiro.au>
+	       Disabled multi-mount capability (use VFS bindings instead).
+	       Work sponsored by SGI.
+  v0.97
+    20000610   Richard Gooch <rgooch@atnf.csiro.au>
+	       Switched to FS_SINGLE to disable multi-mounts.
+    20000612   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed module support.
+	       Removed multi-mount code.
+	       Removed compatibility macros: VFS has changed too much.
+	       Work sponsored by SGI.
+  v0.98
+    20000614   Richard Gooch <rgooch@atnf.csiro.au>
+	       Merged devfs inode into devfs entry.
+	       Work sponsored by SGI.
+  v0.99
+    20000619   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed dead code in <devfs_register> which used to call
+	       <free_dentries>.
+	       Work sponsored by SGI.
+  v0.100
+    20000621   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed interface to <devfs_register>.
+	       Work sponsored by SGI.
+  v0.101
+    20000622   Richard Gooch <rgooch@atnf.csiro.au>
+	       Simplified interface to <devfs_mk_symlink> and <devfs_mk_dir>.
+	       Simplified interface to <devfs_find_handle>.
+	       Work sponsored by SGI.
+  v0.102
+    20010519   Richard Gooch <rgooch@atnf.csiro.au>
+	       Ensure <devfs_generate_path> terminates string for root entry.
+	       Exported <devfs_get_name> to modules.
+    20010520   Richard Gooch <rgooch@atnf.csiro.au>
+	       Make <devfs_mk_symlink> send events to devfsd.
+	       Cleaned up option processing in <devfs_setup>.
+    20010521   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bugs in handling symlinks: could leak or cause Oops.
+    20010522   Richard Gooch <rgooch@atnf.csiro.au>
+	       Cleaned up directory handling by separating fops.
+  v0.103
+    20010601   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed handling of inverted options in <devfs_setup>.
+  v0.104
+    20010604   Richard Gooch <rgooch@atnf.csiro.au>
+	       Adjusted <try_modload> to account for <devfs_generate_path> fix.
+  v0.105
+    20010617   Richard Gooch <rgooch@atnf.csiro.au>
+	       Answered question posed by Al Viro and removed his comments.
+	       Moved setting of registered flag after other fields are changed.
+	       Fixed race between <devfsd_close> and <devfsd_notify_one>.
+	       Global VFS changes added bogus BKL to <devfsd_close>: removed.
+	       Widened locking in <devfs_readlink> and <devfs_follow_link>.
+	       Replaced <devfsd_read> stack usage with <devfsd_ioctl> kmalloc.
+	       Simplified locking in <devfsd_ioctl> and fixed memory leak.
+  v0.106
+    20010709   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed broken devnum allocation and use <devfs_alloc_devnum>.
+	       Fixed old devnum leak by calling new <devfs_dealloc_devnum>.
+  v0.107
+    20010712   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bug in <devfs_setup> which could hang boot process.
+  v0.108
+    20010730   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added DEVFSD_NOTIFY_DELETE event.
+    20010801   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed #include <asm/segment.h>.
+  v0.109
+    20010807   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed inode table races by removing it and using
+	       inode->u.generic_ip instead.
+	       Moved <devfs_read_inode> into <get_vfs_inode>.
+	       Moved <devfs_write_inode> into <devfs_notify_change>.
+  v0.110
+    20010808   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed race in <devfs_do_symlink> for uni-processor.
+  v0.111
+    20010818   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed remnant of multi-mount support in <devfs_mknod>.
+               Removed unused DEVFS_FL_SHOW_UNREG flag.
+  v0.112
+    20010820   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed nlink field from struct devfs_inode.
+  v0.113
+    20010823   Richard Gooch <rgooch@atnf.csiro.au>
+	       Replaced BKL with global rwsem to protect symlink data (quick
+	       and dirty hack).
+  v0.114
+    20010827   Richard Gooch <rgooch@atnf.csiro.au>
+	       Replaced global rwsem for symlink with per-link refcount.
+  v0.115
+    20010919   Richard Gooch <rgooch@atnf.csiro.au>
+	       Set inode->i_mapping->a_ops for block nodes in <get_vfs_inode>.
+  v0.116
+    20011008   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed overrun in <devfs_link> by removing function (not needed).
+    20011009   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed buffer underrun in <try_modload>.
+    20011029   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed race in <devfsd_ioctl> when setting event mask.
+    20011114   Richard Gooch <rgooch@atnf.csiro.au>
+	       First release of new locking code.
+  v1.0
+    20011117   Richard Gooch <rgooch@atnf.csiro.au>
+	       Discard temporary buffer, now use "%s" for dentry names.
+    20011118   Richard Gooch <rgooch@atnf.csiro.au>
+	       Don't generate path in <try_modload>: use fake entry instead.
+	       Use "existing" directory in <_devfs_make_parent_for_leaf>.
+    20011122   Richard Gooch <rgooch@atnf.csiro.au>
+	       Use slab cache rather than fixed buffer for devfsd events.
+  v1.1
+    20011125   Richard Gooch <rgooch@atnf.csiro.au>
+	       Send DEVFSD_NOTIFY_REGISTERED events in <devfs_mk_dir>.
+    20011127   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed locking bug in <devfs_d_revalidate_wait> due to typo.
+	       Do not send CREATE, CHANGE, ASYNC_OPEN or DELETE events from
+	       devfsd or children.
+  v1.2
+    20011202   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bug in <devfsd_read>: was dereferencing freed pointer.
+  v1.3
+    20011203   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed bug in <devfsd_close>: was dereferencing freed pointer.
+	       Added process group check for devfsd privileges.
+  v1.4
+    20011204   Richard Gooch <rgooch@atnf.csiro.au>
+	       Use SLAB_ATOMIC in <devfsd_notify_de> from <devfs_d_delete>.
+  v1.5
+    20011211   Richard Gooch <rgooch@atnf.csiro.au>
+	       Return old entry in <devfs_mk_dir> for 2.4.x kernels.
+    20011212   Richard Gooch <rgooch@atnf.csiro.au>
+	       Increment refcount on module in <check_disc_changed>.
+    20011215   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_get_handle> and exported <devfs_put>.
+	       Increment refcount on module in <devfs_get_ops>.
+	       Created <devfs_put_ops>.
+  v1.6
+    20011216   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added poisoning to <devfs_put>.
+	       Improved debugging messages.
+  v1.7
+    20011221   Richard Gooch <rgooch@atnf.csiro.au>
+	       Corrected (made useful) debugging message in <unregister>.
+	       Moved <kmem_cache_create> in <mount_devfs_fs> to <init_devfs_fs>
+    20011224   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added magic number to guard against scribbling drivers.
+    20011226   Richard Gooch <rgooch@atnf.csiro.au>
+	       Only return old entry in <devfs_mk_dir> if a directory.
+	       Defined macros for error and debug messages.
+  v1.8
+    20020113   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed (rare, old) race in <devfs_lookup>.
+  v1.9
+    20020120   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed deadlock bug in <devfs_d_revalidate_wait>.
+	       Tag VFS deletable in <devfs_mk_symlink> if handle ignored.
+  v1.10
+    20020129   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added KERN_* to remaining messages.
+	       Cleaned up declaration of <stat_read>.
+  v1.11
+    20020219   Richard Gooch <rgooch@atnf.csiro.au>
+	       Changed <devfs_rmdir> to allow later additions if not yet empty.
+  v1.12
+    20020406   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed silently introduced calls to lock_kernel() and
+	       unlock_kernel() due to recent VFS locking changes. BKL isn't
+	       required in devfs.
+  v1.13
+    20020428   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed 2.4.x compatibility code.
+  v1.14
+    20020510   Richard Gooch <rgooch@atnf.csiro.au>
+	       Added BKL to <devfs_open> because drivers still need it.
+  v1.15
+    20020512   Richard Gooch <rgooch@atnf.csiro.au>
+	       Protected <scan_dir_for_removable> and <get_removable_partition>
+	       from changing directory contents.
+  v1.16
+    20020514   Richard Gooch <rgooch@atnf.csiro.au>
+	       Minor cleanup of <scan_dir_for_removable>.
+  v1.17
+    20020721   Richard Gooch <rgooch@atnf.csiro.au>
+	       Switched to ISO C structure field initialisers.
+	       Switch to set_current_state() and move before add_wait_queue().
+    20020722   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed devfs entry leak in <devfs_readdir> when *readdir fails.
+  v1.18
+    20020725   Richard Gooch <rgooch@atnf.csiro.au>
+	       Created <devfs_find_and_unregister>.
+  v1.19
+    20020728   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed deprecated <devfs_find_handle>.
+  v1.20
+    20020820   Richard Gooch <rgooch@atnf.csiro.au>
+	       Fixed module unload race in <devfs_open>.
+  v1.21
+    20021013   Richard Gooch <rgooch@atnf.csiro.au>
+	       Removed DEVFS_ FL_AUTO_OWNER.
+	       Switched lingering structure field initialiser to ISO C.
+	       Added locking when updating FCB flags.
+  v1.22
+*/
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/time.h>
+#include <linux/tty.h>
+#include <linux/timer.h>
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/wait.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/ctype.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/devfs_fs.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/smp_lock.h>
+#include <linux/smp.h>
+#include <linux/rwsem.h>
+#include <linux/sched.h>
+#include <linux/namei.h>
+#include <linux/bitops.h>
+
+#include <asm/uaccess.h>
+#include <asm/io.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/pgtable.h>
+#include <asm/atomic.h>
+
+#define DEVFS_VERSION            "2004-01-31"
+
+#define DEVFS_NAME "devfs"
+
+#define FIRST_INODE 1
+
+#define STRING_LENGTH 256
+#define FAKE_BLOCK_SIZE 1024
+#define POISON_PTR ( *(void **) poison_array )
+#define MAGIC_VALUE 0x327db823
+
+#ifndef TRUE
+#  define TRUE 1
+#  define FALSE 0
+#endif
+
+#define MODE_DIR (S_IFDIR | S_IWUSR | S_IRUGO | S_IXUGO)
+
+#define DEBUG_NONE         0x0000000
+#define DEBUG_MODULE_LOAD  0x0000001
+#define DEBUG_REGISTER     0x0000002
+#define DEBUG_UNREGISTER   0x0000004
+#define DEBUG_FREE         0x0000008
+#define DEBUG_SET_FLAGS    0x0000010
+#define DEBUG_S_READ       0x0000100	/*  Break  */
+#define DEBUG_I_LOOKUP     0x0001000	/*  Break  */
+#define DEBUG_I_CREATE     0x0002000
+#define DEBUG_I_GET        0x0004000
+#define DEBUG_I_CHANGE     0x0008000
+#define DEBUG_I_UNLINK     0x0010000
+#define DEBUG_I_RLINK      0x0020000
+#define DEBUG_I_FLINK      0x0040000
+#define DEBUG_I_MKNOD      0x0080000
+#define DEBUG_F_READDIR    0x0100000	/*  Break  */
+#define DEBUG_D_DELETE     0x1000000	/*  Break  */
+#define DEBUG_D_RELEASE    0x2000000
+#define DEBUG_D_IPUT       0x4000000
+#define DEBUG_ALL          0xfffffff
+#define DEBUG_DISABLED     DEBUG_NONE
+
+#define OPTION_NONE             0x00
+#define OPTION_MOUNT            0x01
+
+#define PRINTK(format, args...) \
+   {printk (KERN_ERR "%s" format, __FUNCTION__ , ## args);}
+
+#define OOPS(format, args...) \
+   {printk (KERN_CRIT "%s" format, __FUNCTION__ , ## args); \
+    printk ("Forcing Oops\n"); \
+    BUG();}
+
+#ifdef CONFIG_DEVFS_DEBUG
+#  define VERIFY_ENTRY(de) \
+   {if ((de) && (de)->magic_number != MAGIC_VALUE) \
+        OOPS ("(%p): bad magic value: %x\n", (de), (de)->magic_number);}
+#  define WRITE_ENTRY_MAGIC(de,magic) (de)->magic_number = (magic)
+#  define DPRINTK(flag, format, args...) \
+   {if (devfs_debug & flag) \
+	printk (KERN_INFO "%s" format, __FUNCTION__ , ## args);}
+#else
+#  define VERIFY_ENTRY(de)
+#  define WRITE_ENTRY_MAGIC(de,magic)
+#  define DPRINTK(flag, format, args...)
+#endif
+
+typedef struct devfs_entry *devfs_handle_t;
+
+struct directory_type {
+	rwlock_t lock;		/*  Lock for searching(R)/updating(W)   */
+	struct devfs_entry *first;
+	struct devfs_entry *last;
+	unsigned char no_more_additions:1;
+};
+
+struct symlink_type {
+	unsigned int length;	/*  Not including the NULL-termimator       */
+	char *linkname;		/*  This is NULL-terminated                 */
+};
+
+struct devfs_inode {		/*  This structure is for "persistent" inode storage  */
+	struct dentry *dentry;
+	struct timespec atime;
+	struct timespec mtime;
+	struct timespec ctime;
+	unsigned int ino;	/*  Inode number as seen in the VFS         */
+	uid_t uid;
+	gid_t gid;
+};
+
+struct devfs_entry {
+#ifdef CONFIG_DEVFS_DEBUG
+	unsigned int magic_number;
+#endif
+	void *info;
+	atomic_t refcount;	/*  When this drops to zero, it's unused    */
+	union {
+		struct directory_type dir;
+		dev_t dev;
+		struct symlink_type symlink;
+		const char *name;	/*  Only used for (mode == 0)               */
+	} u;
+	struct devfs_entry *prev;	/*  Previous entry in the parent directory  */
+	struct devfs_entry *next;	/*  Next entry in the parent directory      */
+	struct devfs_entry *parent;	/*  The parent directory                    */
+	struct devfs_inode inode;
+	umode_t mode;
+	unsigned short namelen;	/*  I think 64k+ filenames are a way off... */
+	unsigned char vfs:1;	/*  Whether the VFS may delete the entry   */
+	char name[1];		/*  This is just a dummy: the allocated array
+				   is bigger. This is NULL-terminated      */
+};
+
+/*  The root of the device tree  */
+static struct devfs_entry *root_entry;
+
+struct devfsd_buf_entry {
+	struct devfs_entry *de;	/*  The name is generated with this         */
+	unsigned short type;	/*  The type of event                       */
+	umode_t mode;
+	uid_t uid;
+	gid_t gid;
+	struct devfsd_buf_entry *next;
+};
+
+struct fs_info {		/*  This structure is for the mounted devfs  */
+	struct super_block *sb;
+	spinlock_t devfsd_buffer_lock;	/*  Lock when inserting/deleting events  */
+	struct devfsd_buf_entry *devfsd_first_event;
+	struct devfsd_buf_entry *devfsd_last_event;
+	volatile int devfsd_sleeping;
+	volatile struct task_struct *devfsd_task;
+	volatile pid_t devfsd_pgrp;
+	volatile struct file *devfsd_file;
+	struct devfsd_notify_struct *devfsd_info;
+	volatile unsigned long devfsd_event_mask;
+	atomic_t devfsd_overrun_count;
+	wait_queue_head_t devfsd_wait_queue;	/*  Wake devfsd on input       */
+	wait_queue_head_t revalidate_wait_queue;	/*  Wake when devfsd sleeps    */
+};
+
+static struct fs_info fs_info = {.devfsd_buffer_lock = SPIN_LOCK_UNLOCKED };
+static kmem_cache_t *devfsd_buf_cache;
+#ifdef CONFIG_DEVFS_DEBUG
+static unsigned int devfs_debug_init __initdata = DEBUG_NONE;
+static unsigned int devfs_debug = DEBUG_NONE;
+static DEFINE_SPINLOCK(stat_lock);
+static unsigned int stat_num_entries;
+static unsigned int stat_num_bytes;
+#endif
+static unsigned char poison_array[8] =
+    { 0x5a, 0x5a, 0x5a, 0x5a, 0x5a, 0x5a, 0x5a, 0x5a };
+
+#ifdef CONFIG_DEVFS_MOUNT
+static unsigned int boot_options = OPTION_MOUNT;
+#else
+static unsigned int boot_options = OPTION_NONE;
+#endif
+
+/*  Forward function declarations  */
+static devfs_handle_t _devfs_walk_path(struct devfs_entry *dir,
+				       const char *name, int namelen,
+				       int traverse_symlink);
+static ssize_t devfsd_read(struct file *file, char __user *buf, size_t len,
+			   loff_t * ppos);
+static int devfsd_ioctl(struct inode *inode, struct file *file,
+			unsigned int cmd, unsigned long arg);
+static int devfsd_close(struct inode *inode, struct file *file);
+#ifdef CONFIG_DEVFS_DEBUG
+static ssize_t stat_read(struct file *file, char __user *buf, size_t len,
+			 loff_t * ppos);
+static struct file_operations stat_fops = {
+	.open = nonseekable_open,
+	.read = stat_read,
+};
+#endif
+
+/*  Devfs daemon file operations  */
+static struct file_operations devfsd_fops = {
+	.open = nonseekable_open,
+	.read = devfsd_read,
+	.ioctl = devfsd_ioctl,
+	.release = devfsd_close,
+};
+
+/*  Support functions follow  */
+
+/**
+ *	devfs_get - Get a reference to a devfs entry.
+ *	@de:  The devfs entry.
+ */
+
+static struct devfs_entry *devfs_get(struct devfs_entry *de)
+{
+	VERIFY_ENTRY(de);