9p: Documentation updates

The kernel-doc comments of much of the 9p system have been in disarray since
reorganization.  This patch fixes those problems, adds additional documentation
and a template book which collects the 9p information.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

fs/9p/fid.h

@@ -22,6 +22,21 @@
 
 #include <linux/list.h>
 
+/**
+ * struct v9fs_dentry - 9p private data stored in dentry d_fsdata
+ * @lock: protects the fidlist
+ * @fidlist: list of FIDs currently associated with this dentry
+ *
+ * This structure defines the 9p private data associated with
+ * a particular dentry.  In particular, this private data is used
+ * to lookup which 9P FID handle should be used for a particular VFS
+ * operation.  FID handles are associated with dentries instead of
+ * inodes in order to more closely map functionality to the Plan 9
+ * expected behavior for FID reclaimation and tracking.
+ *
+ * See Also: Mapping FIDs to Linux VFS model in
+ * Design and Implementation of the Linux 9P File System documentation
+ */
 struct v9fs_dentry {
 	spinlock_t lock; /* protect fidlist */
 	struct list_head fidlist;

fs/9p/v9fs.c

@@ -71,7 +71,6 @@ static match_table_t tokens = {
 
 /**
  * v9fs_parse_options - parse mount options into session structure
- * @options: options string passed from mount
  * @v9ses: existing v9fs session information
  *
  */
@@ -256,9 +255,12 @@ void v9fs_session_close(struct v9fs_session_info *v9ses)
 }
 
 /**
- * v9fs_session_cancel - mark transport as disconnected
- * 	and cancel all pending requests.
+ * v9fs_session_cancel - terminate a session
+ * @v9ses: session to terminate
+ *
+ * mark transport as disconnected and cancel all pending requests.
  */
+
 void v9fs_session_cancel(struct v9fs_session_info *v9ses) {
 	P9_DPRINTK(P9_DEBUG_ERROR, "cancel session %p\n", v9ses);
 	p9_client_disconnect(v9ses->clnt);

fs/9p/v9fs.h

@@ -21,18 +21,69 @@
  *
  */
 
-/*
-  * Session structure provides information for an opened session
-  *
-  */
+/**
+ * enum p9_session_flags - option flags for each 9P session
+ * @V9FS_EXTENDED: whether or not to use 9P2000.u extensions
+ * @V9FS_ACCESS_SINGLE: only the mounting user can access the hierarchy
+ * @V9FS_ACCESS_USER: a new attach will be issued for every user (default)
+ * @V9FS_ACCESS_ANY: use a single attach for all users
+ * @V9FS_ACCESS_MASK: bit mask of different ACCESS options
+ *
+ * Session flags reflect options selected by users at mount time
+ */
+enum p9_session_flags {
+	V9FS_EXTENDED		= 0x01,
+	V9FS_ACCESS_SINGLE	= 0x02,
+	V9FS_ACCESS_USER	= 0x04,
+	V9FS_ACCESS_ANY		= 0x06,
+	V9FS_ACCESS_MASK	= 0x06,
+};
+
+/* possible values of ->cache */
+/**
+ * enum p9_cache_modes - user specified cache preferences
+ * @CACHE_NONE: do not cache data, dentries, or directory contents (default)
+ * @CACHE_LOOSE: cache data, dentries, and directory contents w/no consistency
+ *
+ * eventually support loose, tight, time, session, default always none
+ */
+
+enum p9_cache_modes {
+	CACHE_NONE,
+	CACHE_LOOSE,
+};
+
+/**
+ * struct v9fs_session_info - per-instance session information
+ * @flags: session options of type &p9_session_flags
+ * @nodev: set to 1 to disable device mapping
+ * @debug: debug level
+ * @afid: authentication handle
+ * @cache: cache mode of type &p9_cache_modes
+ * @options: copy of options string given by user
+ * @uname: string user name to mount hierarchy as
+ * @aname: mount specifier for remote hierarchy
+ * @maxdata: maximum data to be sent/recvd per protocol message
+ * @dfltuid: default numeric userid to mount hierarchy as
+ * @dfltgid: default numeric groupid to mount hierarchy as
+ * @uid: if %V9FS_ACCESS_SINGLE, the numeric uid which mounted the hierarchy
+ * @clnt: reference to 9P network client instantiated for this session
+ * @debugfs_dir: reference to debugfs_dir which can be used for add'l debug
+ *
+ * This structure holds state for each session instance established during
+ * a sys_mount() .
+ *
+ * Bugs: there seems to be a lot of state which could be condensed and/or
+ * removed.
+ */
 
 struct v9fs_session_info {
 	/* options */
-	unsigned char flags;	/* session flags */
-	unsigned char nodev;	/* set to 1 if no disable device mapping */
-	unsigned short debug;	/* debug level */
-	unsigned int afid;	/* authentication fid */
-	unsigned int cache;	/* cache mode */
+	unsigned char flags;
+	unsigned char nodev;
+	unsigned short debug;
+	unsigned int afid;
+	unsigned int cache;
 
 	char *options;		/* copy of mount options */
 	char *uname;		/* user name to mount as */
@@ -45,22 +96,6 @@ struct v9fs_session_info {
 	struct dentry *debugfs_dir;
 };
 
-/* session flags */
-enum {
-	V9FS_EXTENDED		= 0x01,	/* 9P2000.u */
-	V9FS_ACCESS_MASK	= 0x06,	/* access mask */
-	V9FS_ACCESS_SINGLE	= 0x02,	/* only one user can access the files */
-	V9FS_ACCESS_USER	= 0x04,	/* attache per user */
-	V9FS_ACCESS_ANY		= 0x06,	/* use the same attach for all users */
-};
-
-/* possible values of ->cache */
-/* eventually support loose, tight, time, session, default always none */
-enum {
-	CACHE_NONE,		/* default */
-	CACHE_LOOSE,		/* no consistency */
-};
-
 extern struct dentry *v9fs_debugfs_root;
 
 struct p9_fid *v9fs_session_init(struct v9fs_session_info *, const char *,

fs/9p/vfs_addr.c

@@ -43,7 +43,7 @@
 /**
  * v9fs_vfs_readpage - read an entire page in from 9P
  *
- * @file: file being read
+ * @filp: file being read
  * @page: structure to page
  *
  */

fs/9p/vfs_dir.c

@@ -60,7 +60,7 @@ static inline int dt_type(struct p9_stat *mistat)
 
 /**
  * v9fs_dir_readdir - read a directory
- * @filep: opened file structure
+ * @filp: opened file structure
  * @dirent: directory structure ???
  * @filldir: function to populate directory structure ???
  *

fs/9p/vfs_file.c

@@ -90,10 +90,11 @@ int v9fs_file_open(struct inode *inode, struct file *file)
 
 /**
  * v9fs_file_lock - lock a file (or directory)
- * @inode: inode to be opened
- * @file: file being opened
+ * @filp: file to be locked
+ * @cmd: lock command
+ * @fl: file lock structure
  *
- * XXX - this looks like a local only lock, we should extend into 9P
+ * Bugs: this looks like a local only lock, we should extend into 9P
  *       by using open exclusive
  */
 
@@ -118,7 +119,7 @@ static int v9fs_file_lock(struct file *filp, int cmd, struct file_lock *fl)
 
 /**
  * v9fs_file_read - read from a file
- * @filep: file pointer to read
+ * @filp: file pointer to read
  * @data: data buffer to read data into
  * @count: size of buffer
  * @offset: offset at which to read data
@@ -142,7 +143,7 @@ v9fs_file_read(struct file *filp, char __user * data, size_t count,
 
 /**
  * v9fs_file_write - write to a file
- * @filep: file pointer to write
+ * @filp: file pointer to write
  * @data: data buffer to write data from
  * @count: size of buffer
  * @offset: offset at which to write data

fs/9p/vfs_inode.c

@@ -129,6 +129,12 @@ static int p9mode2unixmode(struct v9fs_session_info *v9ses, int mode)
 	return res;
 }
 
+/**
+ * v9fs_uflags2omode- convert posix open flags to plan 9 mode bits
+ * @uflags: flags to convert
+ *
+ */
+
 int v9fs_uflags2omode(int uflags)
 {
 	int ret;
@@ -312,6 +318,14 @@ error:
 }
 */
 
+/**
+ * v9fs_inode_from_fid - populate an inode by issuing a attribute request
+ * @v9ses: session information
+ * @fid: fid to issue attribute request for
+ * @sb: superblock on which to create inode
+ *
+ */
+
 static struct inode *
 v9fs_inode_from_fid(struct v9fs_session_info *v9ses, struct p9_fid *fid,
 	struct super_block *sb)
@@ -384,9 +398,12 @@ v9fs_open_created(struct inode *inode, struct file *file)
 
 /**
  * v9fs_create - Create a file
+ * @v9ses: session information
+ * @dir: directory that dentry is being created in
  * @dentry:  dentry that is being created
  * @perm: create permissions
  * @mode: open mode
+ * @extension: 9p2000.u extension string to support devices, etc.
  *
  */
 static struct p9_fid *
@@ -461,7 +478,7 @@ error:
 
 /**
  * v9fs_vfs_create - VFS hook to create files
- * @inode: directory inode that is being created
+ * @dir: directory inode that is being created
  * @dentry:  dentry that is being deleted
  * @mode: create permissions
  * @nd: path information
@@ -519,7 +536,7 @@ error:
 
 /**
  * v9fs_vfs_mkdir - VFS mkdir hook to create a directory
- * @inode:  inode that is being unlinked
+ * @dir:  inode that is being unlinked
  * @dentry: dentry that is being unlinked
  * @mode: mode for new directory
  *
@@ -703,9 +720,9 @@ done:
 
 /**
  * v9fs_vfs_getattr - retrieve file metadata
- * @mnt - mount information
- * @dentry - file to get attributes on
- * @stat - metadata structure to populate
+ * @mnt: mount information
+ * @dentry: file to get attributes on
+ * @stat: metadata structure to populate
  *
  */
 
@@ -928,7 +945,7 @@ done:
 /**
  * v9fs_vfs_readlink - read a symlink's location
  * @dentry: dentry for symlink
- * @buf: buffer to load symlink location into
+ * @buffer: buffer to load symlink location into
  * @buflen: length of buffer
  *
  */
@@ -996,10 +1013,12 @@ static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)
  * v9fs_vfs_put_link - release a symlink path
  * @dentry: dentry for symlink
  * @nd: nameidata
+ * @p: unused
  *
  */
 
-static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
+static void
+v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void *p)
 {
 	char *s = nd_get_link(nd);
 
@@ -1008,6 +1027,15 @@ static void v9fs_vfs_put_link(struct dentry *dentry, struct nameidata *nd, void
 		__putname(s);
 }
 
+/**
+ * v9fs_vfs_mkspecial - create a special file
+ * @dir: inode to create special file in
+ * @dentry: dentry to create
+ * @mode: mode to create special file
+ * @extension: 9p2000.u format extension string representing special file
+ *
+ */
+
 static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
 	int mode, const char *extension)
 {
@@ -1037,7 +1065,7 @@ static int v9fs_vfs_mkspecial(struct inode *dir, struct dentry *dentry,
  * @dentry: dentry for symlink
  * @symname: symlink data
  *
- * See 9P2000.u RFC for more information
+ * See Also: 9P2000.u RFC for more information
  *
  */
 
@@ -1058,10 +1086,6 @@ v9fs_vfs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
  *
  */
 
-/* XXX - lots of code dup'd from symlink and creates,
- * figure out a better reuse strategy
- */
-
 static int
 v9fs_vfs_link(struct dentry *old_dentry, struct inode *dir,
 	      struct dentry *dentry)
@@ -1098,7 +1122,7 @@ clunk_fid:
  * @dir: inode destination for new link
  * @dentry: dentry for file
  * @mode: mode for creation
- * @dev_t: device associated with special file
+ * @rdev: device associated with special file
  *
  */
 

fs/9p/vfs_super.c

@@ -75,6 +75,7 @@ static int v9fs_set_super(struct super_block *s, void *data)
  * v9fs_fill_super - populate superblock with info
  * @sb: superblock
  * @v9ses: session information
+ * @flags: flags propagated from v9fs_get_sb()
  *
  */
 

include/net/9p/9p.h

@@ -29,14 +29,31 @@
 
 #ifdef CONFIG_NET_9P_DEBUG
 
-#define P9_DEBUG_ERROR		(1<<0)
-#define P9_DEBUG_9P	        (1<<2)
-#define P9_DEBUG_VFS	        (1<<3)
-#define P9_DEBUG_CONV		(1<<4)
-#define P9_DEBUG_MUX		(1<<5)
-#define P9_DEBUG_TRANS		(1<<6)
-#define P9_DEBUG_SLABS	      	(1<<7)
-#define P9_DEBUG_FCALL		(1<<8)
+/**
+ * enum p9_debug_flags - bits for mount time debug parameter
+ * @P9_DEBUG_ERROR: more verbose error messages including original error string
+ * @P9_DEBUG_9P: 9P protocol tracing
+ * @P9_DEBUG_VFS: VFS API tracing
+ * @P9_DEBUG_CONV: protocol conversion tracing
+ * @P9_DEBUG_MUX: trace management of concurrent transactions
+ * @P9_DEBUG_TRANS: transport tracing
+ * @P9_DEBUG_SLABS: memory management tracing
+ * @P9_DEBUG_FCALL: verbose dump of protocol messages
+ *
+ * These flags are passed at mount time to turn on various levels of
+ * verbosity and tracing which will be output to the system logs.
+ */
+
+enum p9_debug_flags {
+	P9_DEBUG_ERROR = 	(1<<0),
+	P9_DEBUG_9P = 		(1<<2),
+	P9_DEBUG_VFS =		(1<<3),
+	P9_DEBUG_CONV =		(1<<4),
+	P9_DEBUG_MUX =		(1<<5),
+	P9_DEBUG_TRANS =	(1<<6),
+	P9_DEBUG_SLABS =      	(1<<7),
+	P9_DEBUG_FCALL =	(1<<8),
+};
 
 extern unsigned int p9_debug_level;
 
@@ -62,9 +79,47 @@ do { \
 		format , __FUNCTION__, task_pid_nr(current), ## arg); \
 } while (0)
 
+/**
+ * enum p9_msg_t - 9P message types
+ * @P9_TVERSION: version handshake request
+ * @P9_RVERSION: version handshake response
+ * @P9_TAUTH: request to establish authentication channel
+ * @P9_RAUTH: response with authentication information
+ * @P9_TATTACH: establish user access to file service
+ * @P9_RATTACH: response with top level handle to file hierarchy
+ * @P9_TERROR: not used
+ * @P9_RERROR: response for any failed request
+ * @P9_TFLUSH: request to abort a previous request
+ * @P9_RFLUSH: response when previous request has been cancelled
+ * @P9_TWALK: descend a directory hierarchy
+ * @P9_RWALK: response with new handle for position within hierarchy
+ * @P9_TOPEN: prepare a handle for I/O on an existing file
+ * @P9_ROPEN: response with file access information
+ * @P9_TCREATE: prepare a handle for I/O on a new file
+ * @P9_RCREATE: response with file access information
+ * @P9_TREAD: request to transfer data from a file or directory
+ * @P9_RREAD: response with data requested
+ * @P9_TWRITE: reuqest to transfer data to a file
+ * @P9_RWRITE: response with out much data was transfered to file
+ * @P9_TCLUNK: forget about a handle to an entity within the file system
+ * @P9_RCLUNK: response when server has forgotten about the handle
+ * @P9_TREMOVE: request to remove an entity from the hierarchy
+ * @P9_RREMOVE: response when server has removed the entity
+ * @P9_TSTAT: request file entity attributes
+ * @P9_RSTAT: response with file entity attributes
+ * @P9_TWSTAT: request to update file entity attributes
+ * @P9_RWSTAT: response when file entity attributes are updated
+ *
+ * There are 14 basic operations in 9P2000, paired as
+ * requests and responses.  The one special case is ERROR
+ * as there is no @P9_TERROR request for clients to transmit to
+ * the server, but the server may respond to any other request
+ * with an @P9_RERROR.
+ *
+ * See Also: http://plan9.bell-labs.com/sys/man/5/INDEX.html
+ */
 
-/* Message Types */
-enum {
+enum p9_msg_t {
 	P9_TVERSION = 100,
 	P9_RVERSION,
 	P9_TAUTH = 102,
@@ -95,30 +150,71 @@ enum {
 	P9_RWSTAT,
 };
 
-/* open modes */
-enum {
+/**
+ * enum p9_open_mode_t - 9P open modes
+ * @P9_OREAD: open file for reading only
+ * @P9_OWRITE: open file for writing only
+ * @P9_ORDWR: open file for reading or writing
+ * @P9_OEXEC: open file for execution
+ * @P9_OTRUNC: truncate file to zero-length before opening it
+ * @P9_OREXEC: close the file when an exec(2) system call is made
+ * @P9_ORCLOSE: remove the file when the file is closed
+ * @P9_OAPPEND: open the file and seek to the end
+ * @P9_OEXCL: only create a file, do not open it
+ *
+ * 9P open modes differ slightly from Posix standard modes.
+ * In particular, there are extra modes which specify different
+ * semantic behaviors than may be available on standard Posix
+ * systems.  For example, @P9_OREXEC and @P9_ORCLOSE are modes that
+ * most likely will not be issued from the Linux VFS client, but may
+ * be supported by servers.
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/open
+ */
+
+enum p9_open_mode_t {
 	P9_OREAD = 0x00,
 	P9_OWRITE = 0x01,
 	P9_ORDWR = 0x02,
 	P9_OEXEC = 0x03,
-	P9_OEXCL = 0x04,
 	P9_OTRUNC = 0x10,
 	P9_OREXEC = 0x20,
 	P9_ORCLOSE = 0x40,
 	P9_OAPPEND = 0x80,
-};
-
-/* permissions */
-enum {
+	P9_OEXCL = 0x1000,
+};
+
+/**
+ * enum p9_perm_t - 9P permissions
+ * @P9_DMDIR: mode bite for directories
+ * @P9_DMAPPEND: mode bit for is append-only
+ * @P9_DMEXCL: mode bit for excluse use (only one open handle allowed)
+ * @P9_DMMOUNT: mode bite for mount points
+ * @P9_DMAUTH: mode bit for authentication file
+ * @P9_DMTMP: mode bit for non-backed-up files
+ * @P9_DMSYMLINK: mode bit for symbolic links (9P2000.u)
+ * @P9_DMLINK: mode bit for hard-link (9P2000.u)
+ * @P9_DMDEVICE: mode bit for device files (9P2000.u)
+ * @P9_DMNAMEDPIPE: mode bit for named pipe (9P2000.u)
+ * @P9_DMSOCKET: mode bit for socket (9P2000.u)
+ * @P9_DMSETUID: mode bit for setuid (9P2000.u)
+ * @P9_DMSETGID: mode bit for setgid (9P2000.u)
+ * @P9_DMSETVTX: mode bit for sticky bit (9P2000.u)
+ *
+ * 9P permissions differ slightly from Posix standard modes.
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+enum p9_perm_t {
 	P9_DMDIR = 0x80000000,
 	P9_DMAPPEND = 0x40000000,
 	P9_DMEXCL = 0x20000000,
 	P9_DMMOUNT = 0x10000000,
 	P9_DMAUTH = 0x08000000,
 	P9_DMTMP = 0x04000000,
+/* 9P2000.u extensions */
 	P9_DMSYMLINK = 0x02000000,
 	P9_DMLINK = 0x01000000,
-	/* 9P2000.u extensions */
 	P9_DMDEVICE = 0x00800000,
 	P9_DMNAMEDPIPE = 0x00200000,
 	P9_DMSOCKET = 0x00100000,
@@ -127,8 +223,26 @@ enum {
 	P9_DMSETVTX = 0x00010000,
 };
 
-/* qid.types */
-enum {
+/**
+ * enum p9_qid_t - QID types
+ * @P9_QTDIR: directory
+ * @P9_QTAPPEND: append-only
+ * @P9_QTEXCL: excluse use (only one open handle allowed)
+ * @P9_QTMOUNT: mount points
+ * @P9_QTAUTH: authentication file
+ * @P9_QTTMP: non-backed-up files
+ * @P9_QTSYMLINK: symbolic links (9P2000.u)
+ * @P9_QTLINK: hard-link (9P2000.u)
+ * @P9_QTFILE: normal files
+ *
+ * QID types are a subset of permissions - they are primarily
+ * used to differentiate semantics for a file system entity via
+ * a jump-table.  Their value is also the most signifigant 16 bits
+ * of the permission_t
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+enum p9_qid_t {
 	P9_QTDIR = 0x80,
 	P9_QTAPPEND = 0x40,
 	P9_QTEXCL = 0x20,
@@ -140,6 +254,7 @@ enum {
 	P9_QTFILE = 0x00,
 };
 
+/* 9P Magic Numbers */
 #define P9_NOTAG	(u16)(~0)
 #define P9_NOFID	(u32)(~0)
 #define P9_MAXWELEM	16
@@ -147,19 +262,69 @@ enum {
 /* ample room for Twrite/Rread header */
 #define P9_IOHDRSZ	24
 
+/**
+ * struct p9_str - length prefixed string type
+ * @len: length of the string
+ * @str: the string
+ *
+ * The protocol uses length prefixed strings for all
+ * string data, so we replicate that for our internal
+ * string members.
+ */
+
 struct p9_str {
 	u16 len;
 	char *str;
 };
 
-/* qids are the unique ID for a file (like an inode */
+/**
+ * struct p9_qid - file system entity information
+ * @type: 8-bit type &p9_qid_t
+ * @version: 16-bit monotonically incrementing version number
+ * @path: 64-bit per-server-unique ID for a file system element
+ *
+ * qids are identifiers used by 9P servers to track file system
+ * entities.  The type is used to differentiate semantics for operations
+ * on the entity (ie. read means something different on a directory than
+ * on a file).  The path provides a server unique index for an entity
+ * (roughly analogous to an inode number), while the version is updated
+ * every time a file is modified and can be used to maintain cache
+ * coherency between clients and serves.
+ * Servers will often differentiate purely synthetic entities by setting
+ * their version to 0, signaling that they should never be cached and
+ * should be accessed synchronously.
+ *
+ * See Also://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+
 struct p9_qid {
 	u8 type;
 	u32 version;
 	u64 path;
 };
 
-/* Plan 9 file metadata (stat) structure */
+/**
+ * struct p9_stat - file system metadata information
+ * @size: length prefix for this stat structure instance
+ * @type: the type of the server (equivilent to a major number)
+ * @dev: the sub-type of the server (equivilent to a minor number)
+ * @qid: unique id from the server of type &p9_qid
+ * @mode: Plan 9 format permissions of type &p9_perm_t
+ * @atime: Last access/read time
+ * @mtime: Last modify/write time
+ * @length: file length
+ * @name: last element of path (aka filename) in type &p9_str
+ * @uid: owner name in type &p9_str
+ * @gid: group owner in type &p9_str
+ * @muid: last modifier in type &p9_str
+ * @extension: area used to encode extended UNIX support in type &p9_str
+ * @n_uid: numeric user id of owner (part of 9p2000.u extension)
+ * @n_gid: numeric group id (part of 9p2000.u extension)
+ * @n_muid: numeric user id of laster modifier (part of 9p2000.u extension)
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+
 struct p9_stat {
 	u16 size;
 	u16 type;
@@ -179,10 +344,14 @@ struct p9_stat {
 	u32 n_muid;			/* 9p2000.u extensions */
 };
 
-/* file metadata (stat) structure used to create Twstat message
-   The is similar to p9_stat, but the strings don't point to
-   the same memory block and should be freed separately
-*/
+/*
+ * file metadata (stat) structure used to create Twstat message
+ * The is identical to &p9_stat, but the strings don't point to
+ * the same memory block and should be freed separately
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/stat
+ */
+
 struct p9_wstat {
 	u16 size;
 	u16 type;
@@ -335,10 +504,20 @@ struct p9_twstat {
 struct p9_rwstat {
 };
 
-/*
-  * fcall is the primary packet structure
-  *
-  */
+/**
+ * struct p9_fcall - primary packet structure
+ * @size: prefixed length of the structure
+ * @id: protocol operating identifier of type &p9_msg_t
+ * @tag: transaction id of the request
+ * @sdata: payload
+ * @params: per-operation parameters
+ *
+ * &p9_fcall represents the structure for all 9P RPC
+ * transactions.  Requests are packaged into fcalls, and reponses
+ * must be extracted from them.
+ *
+ * See Also: http://plan9.bell-labs.com/magic/man2html/2/fcall
+ */
 
 struct p9_fcall {
 	u32 size;

include/net/9p/client.h

@@ -26,6 +26,23 @@
 #ifndef NET_9P_CLIENT_H
 #define NET_9P_CLIENT_H
 
+/**
+ * struct p9_client - per client instance state
+ * @lock: protect @fidlist
+ * @msize: maximum data size negotiated by protocol
+ * @dotu: extension flags negotiated by protocol
+ * @trans_mod: module API instantiated with this client
+ * @trans: tranport instance state and API
+ * @conn: connection state information used by trans_fd
+ * @fidpool: fid handle accounting for session
+ * @fidlist: List of active fid handles
+ *
+ * The client structure is used to keep track of various per-client
+ * state that has been instantiated.
+ *
+ * Bugs: duplicated data and potentially unnecessary elements.
+ */
+
 struct p9_client {
 	spinlock_t lock; /* protect client structure */
 	int msize;
@@ -38,6 +55,24 @@ struct p9_client {
 	struct list_head fidlist;
 };
 
+/**
+ * struct p9_fid - file system entity handle
+ * @clnt: back pointer to instantiating &p9_client
+ * @fid: numeric identifier for this handle
+ * @mode: current mode of this fid (enum?)
+ * @qid: the &p9_qid server identifier this handle points to
+ * @iounit: the server reported maximum transaction size for this file
+ * @uid: the numeric uid of the local user who owns this handle
+ * @aux: transport specific information (unused?)
+ * @rdir_fpos: tracks offset of file position when reading directory contents
+ * @rdir_pos: (unused?)
+ * @rdir_fcall: holds response of last directory read request
+ * @flist: per-client-instance fid tracking
+ * @dlist: per-dentry fid tracking
+ *
+ * TODO: This needs lots of explanation.
+ */
+
 struct p9_fid {
 	struct p9_client *clnt;
 	u32 fid;

include/net/9p/transport.h

@@ -26,12 +26,40 @@
 #ifndef NET_9P_TRANSPORT_H
 #define NET_9P_TRANSPORT_H
 
+/**
+ * enum p9_trans_status - different states of underlying transports
+ * @Connected: transport is connected and healthy
+ * @Disconnected: transport has been disconnected
+ * @Hung: transport is connected by wedged
+ *
+ * This enumeration details the various states a transport
+ * instatiation can be in.
+ */
+
 enum p9_trans_status {
 	Connected,
 	Disconnected,
 	Hung,
 };
 
+/**
+ * struct p9_trans - per-transport state and API
+ * @status: transport &p9_trans_status
+ * @msize: negotiated maximum packet size (duplicate from client)
+ * @extended: negotiated protocol extensions (duplicate from client)
+ * @priv: transport private data
+ * @close: member function to disconnect and close the transport
+ * @rpc: member function to issue a request to the transport
+ *
+ * This is the basic API for a transport instance.  It is used as
+ * a handle by the client to issue requests.  This interface is currently
+ * in flux during reorganization.
+ *
+ * Bugs: there is lots of duplicated data here and its not clear that
+ * the member functions need to be per-instance versus per transport
+ * module.
+ */
+
 struct p9_trans {
 	enum p9_trans_status status;
 	int msize;
@@ -42,6 +70,21 @@ struct p9_trans {
 							struct p9_fcall **rc);
 };
 
+/**
+ * struct p9_trans_module - transport module interface
+ * @list: used to maintain a list of currently available transports
+ * @name: the human-readable name of the transport
+ * @maxsize: transport provided maximum packet size
+ * @def: set if this transport should be considered the default
+ * @create: member function to create a new connection on this transport
+ *
+ * This is the basic API for a transport module which is registered by the
+ * transport module with the 9P core network module and used by the client
+ * to instantiate a new connection on a transport.
+ *
+ * Bugs: the transport module list isn't protected.
+ */
+
 struct p9_trans_module {
 	struct list_head list;
 	char *name;		/* name of transport */

net/9p/conv.c

@@ -197,7 +197,7 @@ static void buf_get_qid(struct cbuf *bufp, struct p9_qid *qid)
 
 /**
  * p9_size_wstat - calculate the size of a variable length stat struct
- * @stat: metadata (stat) structure
+ * @wstat: metadata (stat) structure
  * @dotu: non-zero if 9P2000.u
  *
  */
@@ -511,6 +511,12 @@ p9_create_common(struct cbuf *bufp, u32 size, u8 id)
 	return fc;
 }
 
+/**
+ * p9_set_tag - set the tag field of an &p9_fcall structure
+ * @fc: fcall structure to set tag within
+ * @tag: tag id to set
+ */
+
 void p9_set_tag(struct p9_fcall *fc, u16 tag)
 {
 	fc->tag = tag;
@@ -518,6 +524,12 @@ void p9_set_tag(struct p9_fcall *fc, u16 tag)
 }
 EXPORT_SYMBOL(p9_set_tag);
 
+/**
+ * p9_create_tversion - allocates and creates a T_VERSION request
+ * @msize: requested maximum data size
+ * @version: version string to negotiate
+ *
+ */
 struct p9_fcall *p9_create_tversion(u32 msize, char *version)
 {
 	int size;
@@ -542,6 +554,16 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tversion);
 
+/**
+ * p9_create_tauth - allocates and creates a T_AUTH request
+ * @afid: handle to use for authentication protocol
+ * @uname: user name attempting to authenticate
+ * @aname: mount specifier for remote server
+ * @n_uname: numeric id for user attempting to authneticate
+ * @dotu: 9P2000.u extension flag
+ *
+ */
+
 struct p9_fcall *p9_create_tauth(u32 afid, char *uname, char *aname,
 	u32 n_uname, int dotu)
 {
@@ -580,6 +602,18 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tauth);
 
+/**
+ * p9_create_tattach - allocates and creates a T_ATTACH request
+ * @fid: handle to use for the new mount point
+ * @afid: handle to use for authentication protocol
+ * @uname: user name attempting to attach
+ * @aname: mount specifier for remote server
+ * @n_uname: numeric id for user attempting to attach
+ * @n_uname: numeric id for user attempting to attach
+ * @dotu: 9P2000.u extension flag
+ *
+ */
+
 struct p9_fcall *
 p9_create_tattach(u32 fid, u32 afid, char *uname, char *aname,
 	u32 n_uname, int dotu)
@@ -616,6 +650,12 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tattach);
 
+/**
+ * p9_create_tflush - allocates and creates a T_FLUSH request
+ * @oldtag: tag id for the transaction we are attempting to cancel
+ *
+ */
+
 struct p9_fcall *p9_create_tflush(u16 oldtag)
 {
 	int size;
@@ -639,6 +679,15 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tflush);
 
+/**
+ * p9_create_twalk - allocates and creates a T_FLUSH request
+ * @fid: handle we are traversing from
+ * @newfid: a new handle for this transaction
+ * @nwname: number of path elements to traverse
+ * @wnames: array of path elements
+ *
+ */
+
 struct p9_fcall *p9_create_twalk(u32 fid, u32 newfid, u16 nwname,
 				     char **wnames)
 {
@@ -677,6 +726,13 @@ error:
 }
 EXPORT_SYMBOL(p9_create_twalk);
 
+/**
+ * p9_create_topen - allocates and creates a T_OPEN request
+ * @fid: handle we are trying to open
+ * @mode: what mode we are trying to open the file in
+ *
+ */
+
 struct p9_fcall *p9_create_topen(u32 fid, u8 mode)
 {
 	int size;
@@ -701,6 +757,19 @@ error:
 }
 EXPORT_SYMBOL(p9_create_topen);
 
+/**
+ * p9_create_tcreate - allocates and creates a T_CREATE request
+ * @fid: handle of directory we are trying to create in
+ * @name: name of the file we are trying to create
+ * @perm: permissions for the file we are trying to create
+ * @mode: what mode we are trying to open the file in
+ * @extension: 9p2000.u extension string (for special files)
+ * @dotu: 9p2000.u enabled flag
+ *
+ * Note: Plan 9 create semantics include opening the resulting file
+ * which is why mode is included.
+ */
+
 struct p9_fcall *p9_create_tcreate(u32 fid, char *name, u32 perm, u8 mode,
 	char *extension, int dotu)
 {
@@ -736,6 +805,13 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tcreate);
 
+/**
+ * p9_create_tread - allocates and creates a T_READ request
+ * @fid: handle of the file we are trying to read
+ * @offset: offset to start reading from
+ * @count: how many bytes to read
+ */
+
 struct p9_fcall *p9_create_tread(u32 fid, u64 offset, u32 count)
 {
 	int size;
@@ -761,6 +837,17 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tread);
 
+/**
+ * p9_create_twrite - allocates and creates a T_WRITE request from the kernel
+ * @fid: handle of the file we are trying to write
+ * @offset: offset to start writing at
+ * @count: how many bytes to write
+ * @data: data to write
+ *
+ * This function will create a requst with data buffers from the kernel
+ * such as the page cache.
+ */
+
 struct p9_fcall *p9_create_twrite(u32 fid, u64 offset, u32 count,
 				      const char *data)
 {
@@ -794,6 +881,16 @@ error:
 }
 EXPORT_SYMBOL(p9_create_twrite);
 
+/**
+ * p9_create_twrite_u - allocates and creates a T_WRITE request from userspace
+ * @fid: handle of the file we are trying to write
+ * @offset: offset to start writing at
+ * @count: how many bytes to write
+ * @data: data to write
+ *
+ * This function will create a request with data buffers from userspace
+ */
+
 struct p9_fcall *p9_create_twrite_u(u32 fid, u64 offset, u32 count,
 				      const char __user *data)
 {
@@ -827,6 +924,14 @@ error:
 }
 EXPORT_SYMBOL(p9_create_twrite_u);
 
+/**
+ * p9_create_tclunk - allocate a request to forget about a file handle
+ * @fid: handle of the file we closing or forgetting about
+ *
+ * clunk is used both to close open files and to discard transient handles
+ * which may be created during meta-data operations and hierarchy traversal.
+ */
+
 struct p9_fcall *p9_create_tclunk(u32 fid)
 {
 	int size;
@@ -850,6 +955,12 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tclunk);
 
+/**
+ * p9_create_tremove - allocate and create a request to remove a file
+ * @fid: handle of the file or directory we are removing
+ *
+ */
+
 struct p9_fcall *p9_create_tremove(u32 fid)
 {
 	int size;
@@ -873,6 +984,12 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tremove);
 
+/**
+ * p9_create_tstat - allocate and populate a request for attributes
+ * @fid: handle of the file or directory we are trying to get the attributes of
+ *
+ */
+
 struct p9_fcall *p9_create_tstat(u32 fid)
 {
 	int size;
@@ -896,6 +1013,14 @@ error:
 }
 EXPORT_SYMBOL(p9_create_tstat);
 
+/**
+ * p9_create_tstat - allocate and populate a request to change attributes
+ * @fid: handle of the file or directory we are trying to change
+ * @wstat: &p9_stat structure with attributes we wish to set
+ * @dotu: 9p2000.u enabled flag
+ *
+ */
+
 struct p9_fcall *p9_create_twstat(u32 fid, struct p9_wstat *wstat,
 				      int dotu)
 {
@@ -922,3 +1047,4 @@ error:
 	return fc;
 }
 EXPORT_SYMBOL(p9_create_twstat);
+

net/9p/error.c

@@ -33,6 +33,13 @@
 #include <linux/errno.h>
 #include <net/9p/9p.h>
 
+/**
+ * struct errormap - map string errors from Plan 9 to Linux numeric ids
+ * @name: string sent over 9P
+ * @val: numeric id most closely representing @name
+ * @namelen: length of string
+ * @list: hash-table list for string lookup
+ */
 struct errormap {
 	char *name;
 	int val;
@@ -177,8 +184,7 @@ static struct errormap errmap[] = {
 };
 
 /**
- * p9_error_init - preload
- * @errstr: error string
+ * p9_error_init - preload mappings into hash list
  *
  */
 
@@ -206,6 +212,7 @@ EXPORT_SYMBOL(p9_error_init);
 /**
  * errstr2errno - convert error string to error number
  * @errstr: error string
+ * @len: length of error string
  *
  */
 

net/9p/fcprint.c

@@ -142,6 +142,14 @@ p9_printdata(char *buf, int buflen, u8 *data, int datalen)
 	return p9_dumpdata(buf, buflen, data, datalen < 16?datalen:16);
 }
 
+/**
+ * p9_printfcall - decode and print a protocol structure into a buffer
+ * @buf: buffer to deposit decoded structure into
+ * @buflen: available space in buffer
+ * @fc: protocol rpc structure of type &p9_fcall
+ * @extended: whether or not session is operating with extended protocol
+ */
+
 int
 p9_printfcall(char *buf, int buflen, struct p9_fcall *fc, int extended)
 {

net/9p/mod.c

@@ -39,9 +39,6 @@ module_param_named(debug, p9_debug_level, uint, 0);
 MODULE_PARM_DESC(debug, "9P debugging level");
 #endif
 
-extern int p9_mux_global_init(void);
-extern void p9_mux_global_exit(void);
-
 /*
  * Dynamic Transport Registration Routines
  *
@@ -52,7 +49,7 @@ static struct p9_trans_module *v9fs_default_transport;
 
 /**
  * v9fs_register_trans - register a new transport with 9p
- * @m - structure describing the transport module and entry points
+ * @m: structure describing the transport module and entry points
  *
  */
 void v9fs_register_trans(struct p9_trans_module *m)
@@ -65,7 +62,7 @@ EXPORT_SYMBOL(v9fs_register_trans);
 
 /**
  * v9fs_match_trans - match transport versus registered transports
- * @arg: string identifying transport
+ * @name: string identifying transport
  *
  */
 struct p9_trans_module *v9fs_match_trans(const substring_t *name)

net/9p/trans_fd.c

@@ -47,12 +47,29 @@
 #define SCHED_TIMEOUT	10
 #define MAXPOLLWADDR	2
 
+/**
+ * struct p9_fd_opts - per-transport options
+ * @rfd: file descriptor for reading (trans=fd)
+ * @wfd: file descriptor for writing (trans=fd)
+ * @port: port to connect to (trans=tcp)
+ *
+ */
+
 struct p9_fd_opts {
 	int rfd;
 	int wfd;
 	u16 port;
 };
 
+
+/**
+ * struct p9_trans_fd - transport state
+ * @rd: reference to file to read from
+ * @wr: reference of file to write to
+ * @conn: connection state reference
+ *
+ */
+
 struct p9_trans_fd {
 	struct file *rd;
 	struct file *wr;
@@ -90,10 +107,24 @@ enum {
 };
 
 struct p9_req;
-
 typedef void (*p9_conn_req_callback)(struct p9_req *req, void *a);
+
+/**
+ * struct p9_req - fd mux encoding of an rpc transaction
+ * @lock: protects req_list
+ * @tag: numeric tag for rpc transaction
+ * @tcall: request &p9_fcall structure
+ * @rcall: response &p9_fcall structure
+ * @err: error state
+ * @cb: callback for when response is received
+ * @cba: argument to pass to callback
+ * @flush: flag to indicate RPC has been flushed
+ * @req_list: list link for higher level objects to chain requests
+ *
+ */
+
 struct p9_req {
-	spinlock_t lock; /* protect request structure */
+	spinlock_t lock;
 	int tag;
 	struct p9_fcall *tcall;
 	struct p9_fcall *rcall;
@@ -104,7 +135,39 @@ struct p9_req {
 	struct list_head req_list;
 };
 
-struct p9_mux_poll_task;
+struct p9_mux_poll_task {
+	struct task_struct *task;
+	struct list_head mux_list;
+	int muxnum;
+};
+
+/**
+ * struct p9_conn - fd mux connection state information
+ * @lock: protects mux_list (?)
+ * @mux_list: list link for mux to manage multiple connections (?)
+ * @poll_task: task polling on this connection
+ * @msize: maximum size for connection (dup)
+ * @extended: 9p2000.u flag (dup)
+ * @trans: reference to transport instance for this connection
+ * @tagpool: id accounting for transactions
+ * @err: error state
+ * @equeue: event wait_q (?)
+ * @req_list: accounting for requests which have been sent
+ * @unsent_req_list: accounting for requests that haven't been sent
+ * @rcall: current response &p9_fcall structure
+ * @rpos: read position in current frame
+ * @rbuf: current read buffer
+ * @wpos: write position for current frame
+ * @wsize: amount of data to write for current frame
+ * @wbuf: current write buffer
+ * @poll_wait: array of wait_q's for various worker threads
+ * @poll_waddr: ????
+ * @pt: poll state
+ * @rq: current read work
+ * @wq: current write work
+ * @wsched: ????
+ *
+ */
 
 struct p9_conn {
 	spinlock_t lock; /* protect lock structure */
@@ -132,11 +195,16 @@ struct p9_conn {
 	unsigned long wsched;
 };
 
-struct p9_mux_poll_task {
-	struct task_struct *task;
-	struct list_head mux_list;
-	int muxnum;
-};
+/**
+ * struct p9_mux_rpc - fd mux rpc accounting structure
+ * @m: connection this request was issued on
+ * @err: error state
+ * @tcall: request &p9_fcall
+ * @rcall: response &p9_fcall
+ * @wqueue: wait queue that client is blocked on for this rpc
+ *
+ * Bug: isn't this information duplicated elsewhere like &p9_req
+ */
 
 struct p9_mux_rpc {
 	struct p9_conn *m;
@@ -207,10 +275,12 @@ static void p9_mux_put_tag(struct p9_conn *m, u16 tag)
 
 /**
  * p9_mux_calc_poll_procs - calculates the number of polling procs
- * based on the number of mounted v9fs filesystems.
+ * @muxnum: number of mounts
  *
+ * Calculation is based on the number of mounted v9fs filesystems.
  * The current implementation returns sqrt of the number of mounts.
  */
+
 static int p9_mux_calc_poll_procs(int muxnum)
 {
 	int n;
@@ -331,12 +401,11 @@ static void p9_mux_poll_stop(struct p9_conn *m)
 
 /**
  * p9_conn_create - allocate and initialize the per-session mux data
- * Creates the polling task if this is the first session.
+ * @trans: transport structure
  *
- * @trans - transport structure
- * @msize - maximum message size
- * @extended - extended flag
+ * Note: Creates the polling task if this is the first session.
  */
+
 static struct p9_conn *p9_conn_create(struct p9_trans *trans)
 {
 	int i, n;
@@ -406,7 +475,10 @@ static struct p9_conn *p9_conn_create(struct p9_trans *trans)
 
 /**
  * p9_mux_destroy - cancels all pending requests and frees mux resources
+ * @m: mux to destroy
+ *
  */
+
 static void p9_conn_destroy(struct p9_conn *m)
 {
 	P9_DPRINTK(P9_DEBUG_MUX, "mux %p prev %p next %p\n", m,
@@ -429,9 +501,14 @@ static void p9_conn_destroy(struct p9_conn *m)
 }
 
 /**
- * p9_pollwait - called by files poll operation to add v9fs-poll task
- * 	to files wait queue
+ * p9_pollwait - add poll task to the wait queue
+ * @filp: file pointer being polled
+ * @wait_address: wait_q to block on
+ * @p: poll state
+ *
+ * called by files poll operation to add v9fs-poll task to files wait queue
  */
+
 static void
 p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 {
@@ -462,7 +539,10 @@ p9_pollwait(struct file *filp, wait_queue_head_t *wait_address, poll_table *p)
 
 /**
  * p9_poll_mux - polls a mux and schedules read or write works if necessary
+ * @m: connection to poll
+ *
  */
+
 static void p9_poll_mux(struct p9_conn *m)
 {
 	int n;
@@ -499,9 +579,14 @@ static void p9_poll_mux(struct p9_conn *m)
 }
 
 /**
- * p9_poll_proc - polls all v9fs transports for new events and queues
- * 	the appropriate work to the work queue
+ * p9_poll_proc - poll worker thread
+ * @a: thread state and arguments
+ *
+ * polls all v9fs transports for new events and queues the appropriate
+ * work to the work queue
+ *
  */
+
 static int p9_poll_proc(void *a)
 {
 	struct p9_conn *m, *mtmp;
@@ -527,7 +612,10 @@ static int p9_poll_proc(void *a)
 
 /**
  * p9_write_work - called when a transport can send some data
+ * @work: container for work to be done
+ *
  */
+
 static void p9_write_work(struct work_struct *work)
 {
 	int n, err;
@@ -638,7 +726,10 @@ static void process_request(struct p9_conn *m, struct p9_req *req)
 
 /**
  * p9_read_work - called when there is some data to be read from a transport
+ * @work: container of work to be done
+ *
  */
+
 static void p9_read_work(struct work_struct *work)
 {
 	int n, err;
@@ -793,7 +884,9 @@ error:
  * @tc: request to be sent
  * @cb: callback function to call when response is received
  * @cba: parameter to pass to the callback function
+ *
  */
+
 static struct p9_req *p9_send_request(struct p9_conn *m,
 					  struct p9_fcall *tc,
 					  p9_conn_req_callback cb, void *cba)
@@ -961,10 +1054,12 @@ p9_conn_rpc_cb(struct p9_req *req, void *a)
 /**
  * p9_fd_rpc- sends 9P request and waits until a response is available.
  *	The function can be interrupted.
- * @m: mux data
+ * @t: transport data
  * @tc: request to be sent
  * @rc: pointer where a pointer to the response is stored
+ *
  */
+
 int
 p9_fd_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
 {
@@ -1041,8 +1136,10 @@ p9_fd_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
  * @m: mux data
  * @tc: request to be sent
  * @cb: callback function to be called when response arrives
- * @cba: value to pass to the callback function
+ * @a: value to pass to the callback function
+ *
  */
+
 int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
 		   p9_conn_req_callback cb, void *a)
 {
@@ -1065,7 +1162,9 @@ int p9_conn_rpcnb(struct p9_conn *m, struct p9_fcall *tc,
  * p9_conn_cancel - cancel all pending requests with error
  * @m: mux data
  * @err: error code
+ *
  */
+
 void p9_conn_cancel(struct p9_conn *m, int err)
 {
 	struct p9_req *req, *rtmp;
@@ -1099,7 +1198,7 @@ void p9_conn_cancel(struct p9_conn *m, int err)
 /**
  * v9fs_parse_options - parse mount options into session structure
  * @options: options string passed from mount
- * @v9ses: existing v9fs session information
+ * @opts: transport-specific structure to parse options into
  *
  */
 
@@ -1193,11 +1292,12 @@ static int p9_socket_open(struct p9_trans *trans, struct socket *csocket)
 
 /**
  * p9_fd_read- read from a fd
- * @v9ses: session information
+ * @trans: transport instance state
  * @v: buffer to receive data into
  * @len: size of receive buffer
  *
  */
+
 static int p9_fd_read(struct p9_trans *trans, void *v, int len)
 {
 	int ret;
@@ -1220,11 +1320,12 @@ static int p9_fd_read(struct p9_trans *trans, void *v, int len)
 
 /**
  * p9_fd_write - write to a socket
- * @v9ses: session information
+ * @trans: transport instance state
  * @v: buffer to send data from
  * @len: size of send buffer
  *
  */
+
 static int p9_fd_write(struct p9_trans *trans, void *v, int len)
 {
 	int ret;
@@ -1296,6 +1397,7 @@ end:
  * @trans: private socket structure
  *
  */
+
 static void p9_fd_close(struct p9_trans *trans)
 {
 	struct p9_trans_fd *ts;

net/9p/trans_virtio.c

@@ -55,23 +55,69 @@ static int chan_index;
 
 #define P9_INIT_MAXTAG	16
 
-#define REQ_STATUS_IDLE	0
-#define REQ_STATUS_SENT 1
-#define REQ_STATUS_RCVD 2
-#define REQ_STATUS_FLSH 3
+
+/**
+ * enum p9_req_status_t - virtio request status
+ * @REQ_STATUS_IDLE: request slot unused
+ * @REQ_STATUS_SENT: request sent to server
+ * @REQ_STATUS_RCVD: response received from server
+ * @REQ_STATUS_FLSH: request has been flushed
+ *
+ * The @REQ_STATUS_IDLE state is used to mark a request slot as unused
+ * but use is actually tracked by the idpool structure which handles tag
+ * id allocation.
+ *
+ */
+
+enum p9_req_status_t {
+	REQ_STATUS_IDLE,
+	REQ_STATUS_SENT,
+	REQ_STATUS_RCVD,
+	REQ_STATUS_FLSH,
+};
+
+/**
+ * struct p9_req_t - virtio request slots
+ * @status: status of this request slot
+ * @wq: wait_queue for the client to block on for this request
+ *
+ * The virtio transport uses an array to track outstanding requests
+ * instead of a list.  While this may incurr overhead during initial
+ * allocation or expansion, it makes request lookup much easier as the
+ * tag id is a index into an array.  (We use tag+1 so that we can accomodate
+ * the -1 tag for the T_VERSION request).
+ * This also has the nice effect of only having to allocate wait_queues
+ * once, instead of constantly allocating and freeing them.  Its possible
+ * other resources could benefit from this scheme as well.
+ *
+ */
 
 struct p9_req_t {
 	int status;
 	wait_queue_head_t *wq;
 };
 
-/* We keep all per-channel information in a structure.
+/**
+ * struct virtio_chan - per-instance transport information
+ * @initialized: whether the channel is initialized
+ * @inuse: whether the channel is in use
+ * @lock: protects multiple elements within this structure
+ * @vdev: virtio dev associated with this channel
+ * @vq: virtio queue associated with this channel
+ * @tagpool: accounting for tag ids (and request slots)
+ * @reqs: array of request slots
+ * @max_tag: current number of request_slots allocated
+ * @sg: scatter gather list which is used to pack a request (protected?)
+ *
+ * We keep all per-channel information in a structure.
  * This structure is allocated within the devices dev->mem space.
  * A pointer to the structure will get put in the transport private.
+ *
  */
+
 static struct virtio_chan {
-	bool initialized;		/* channel is initialized */
-	bool inuse;			/* channel is in use */
+	bool initialized;
+	bool inuse;
 
 	spinlock_t lock;
 
@@ -86,7 +132,19 @@ static struct virtio_chan {
 	struct scatterlist sg[VIRTQUEUE_NUM];
 } channels[MAX_9P_CHAN];
 
-/* Lookup requests by tag */
+/**
+ * p9_lookup_tag - Lookup requests by tag
+ * @c: virtio channel to lookup tag within
+ * @tag: numeric id for transaction
+ *
+ * this is a simple array lookup, but will grow the
+ * request_slots as necessary to accomodate transaction
+ * ids which did not previously have a slot.
+ *
+ * Bugs: there is currently no upper limit on request slots set
+ * here, but that should be constrained by the id accounting.
+ */
+
 static struct p9_req_t *p9_lookup_tag(struct virtio_chan *c, u16 tag)
 {
 	/* This looks up the original request by tag so we know which
@@ -130,6 +188,15 @@ static unsigned int rest_of_page(void *data)
 	return PAGE_SIZE - ((unsigned long)data % PAGE_SIZE);
 }
 
+/**
+ * p9_virtio_close - reclaim resources of a channel
+ * @trans: transport state
+ *
+ * This reclaims a channel by freeing its resources and
+ * reseting its inuse flag.
+ *
+ */
+
 static void p9_virtio_close(struct p9_trans *trans)
 {
 	struct virtio_chan *chan = trans->priv;
@@ -151,6 +218,19 @@ static void p9_virtio_close(struct p9_trans *trans)
 	kfree(trans);
 }
 
+/**
+ * req_done - callback which signals activity from the server
+ * @vq: virtio queue activity was received on
+ *
+ * This notifies us that the server has triggered some activity
+ * on the virtio channel - most likely a response to request we
+ * sent.  Figure out which requests now have responses and wake up
+ * those threads.
+ *
+ * Bugs: could do with some additional sanity checking, but appears to work.
+ *
+ */
+
 static void req_done(struct virtqueue *vq)
 {
 	struct virtio_chan *chan = vq->vdev->priv;
@@ -169,6 +249,20 @@ static void req_done(struct virtqueue *vq)
 	spin_unlock_irqrestore(&chan->lock, flags);
 }
 
+/**
+ * pack_sg_list - pack a scatter gather list from a linear buffer
+ * @sg: scatter/gather list to pack into
+ * @start: which segment of the sg_list to start at
+ * @limit: maximum segment to pack data to
+ * @data: data to pack into scatter/gather list
+ * @count: amount of data to pack into the scatter/gather list
+ *
+ * sg_lists have multiple segments of various sizes.  This will pack
+ * arbitrary data into an existing scatter gather list, segmenting the
+ * data as necessary within constraints.
+ *
+ */
+
 static int
 pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
 								int count)
@@ -189,6 +283,14 @@ pack_sg_list(struct scatterlist *sg, int start, int limit, char *data,
 	return index-start;
 }
 
+/**
+ * p9_virtio_rpc - issue a request and wait for a response
+ * @t: transport state
+ * @tc: &p9_fcall request to transmit
+ * @rc: &p9_fcall to put reponse into
+ *
+ */
+
 static int
 p9_virtio_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
 {
@@ -263,6 +365,16 @@ p9_virtio_rpc(struct p9_trans *t, struct p9_fcall *tc, struct p9_fcall **rc)
 	return 0;
 }
 
+/**
+ * p9_virtio_probe - probe for existence of 9P virtio channels
+ * @vdev: virtio device to probe
+ *
+ * This probes for existing virtio channels.  At present only
+ * a single channel is in use, so in the future more work may need
+ * to be done here.
+ *
+ */
+
 static int p9_virtio_probe(struct virtio_device *vdev)
 {
 	int err;
@@ -307,11 +419,28 @@ fail:
 	return err;
 }
 
-/* This sets up a transport channel for 9p communication.  Right now
+
+/**
+ * p9_virtio_create - allocate a new virtio channel
+ * @devname: string identifying the channel to connect to (unused)
+ * @args: args passed from sys_mount() for per-transport options (unused)
+ * @msize: requested maximum packet size
+ * @extended: 9p2000.u enabled flag
+ *
+ * This sets up a transport channel for 9p communication.  Right now
  * we only match the first available channel, but eventually we couldlook up
  * alternate channels by matching devname versus a virtio_config entry.
  * We use a simple reference count mechanism to ensure that only a single
- * mount has a channel open at a time. */
+ * mount has a channel open at a time.
+ *
+ * Bugs: doesn't allow identification of a specific channel
+ * to allocate, channels are allocated sequentially. This was
+ * a pragmatic decision to get things rolling, but ideally some
+ * way of identifying the channel to attach to would be nice
+ * if we are going to support multiple channels.
+ *
+ */
+
 static struct p9_trans *
 p9_virtio_create(const char *devname, char *args, int msize,
 							unsigned char extended)
@@ -360,6 +489,12 @@ p9_virtio_create(const char *devname, char *args, int msize,
 	return trans;
 }
 
+/**
+ * p9_virtio_remove - clean up resources associated with a virtio device
+ * @vdev: virtio device to remove
+ *
+ */
+
 static void p9_virtio_remove(struct virtio_device *vdev)
 {
 	struct virtio_chan *chan = vdev->priv;

net/9p/util.c

@@ -32,11 +32,23 @@
 #include <linux/idr.h>
 #include <net/9p/9p.h>
 
+/**
+ * struct p9_idpool - per-connection accounting for tag idpool
+ * @lock: protects the pool
+ * @pool: idr to allocate tag id from
+ *
+ */
+
 struct p9_idpool {
 	spinlock_t lock;
 	struct idr pool;
 };
 
+/**
+ * p9_idpool_create - create a new per-connection id pool
+ *
+ */
+
 struct p9_idpool *p9_idpool_create(void)
 {
 	struct p9_idpool *p;
@@ -52,6 +64,11 @@ struct p9_idpool *p9_idpool_create(void)
 }
 EXPORT_SYMBOL(p9_idpool_create);
 
+/**
+ * p9_idpool_destroy - create a new per-connection id pool
+ * @p: idpool to destory
+ */
+
 void p9_idpool_destroy(struct p9_idpool *p)
 {
 	idr_destroy(&p->pool);
@@ -61,9 +78,9 @@ EXPORT_SYMBOL(p9_idpool_destroy);
 
 /**
  * p9_idpool_get - allocate numeric id from pool
- * @p - pool to allocate from
+ * @p: pool to allocate from
  *
- * XXX - This seems to be an awful generic function, should it be in idr.c with
+ * Bugs: This seems to be an awful generic function, should it be in idr.c with
  *            the lock included in struct idr?
  */
 
@@ -94,9 +111,10 @@ EXPORT_SYMBOL(p9_idpool_get);
 
 /**
  * p9_idpool_put - release numeric id from pool
- * @p - pool to allocate from
+ * @id: numeric id which is being released
+ * @p: pool to release id into
  *
- * XXX - This seems to be an awful generic function, should it be in idr.c with
+ * Bugs: This seems to be an awful generic function, should it be in idr.c with
  *            the lock included in struct idr?
  */
 
@@ -111,11 +129,13 @@ EXPORT_SYMBOL(p9_idpool_put);
 
 /**
  * p9_idpool_check - check if the specified id is available
- * @id - id to check
- * @p - pool
+ * @id: id to check
+ * @p: pool to check
  */
+
 int p9_idpool_check(int id, struct p9_idpool *p)
 {
 	return idr_find(&p->pool, id) != NULL;
 }
 EXPORT_SYMBOL(p9_idpool_check);
+