Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs

* 'for-linus' of ssh://master.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs:
  9p: fix error path during early mount
  9p: make cryptic unknown error from server less scary
  9p: fix flags length in net
  9p: Correct fidpool creation failure in p9_client_create
  9p: use struct mutex instead of struct semaphore
  9p: propagate parse_option changes to client and transports
  fs/9p/v9fs.c (v9fs_parse_options): Handle kstrdup and match_strdup failure.
  9p: Documentation updates
  add match_strlcpy() us it to make v9fs make uname and remotename parsing more robust

10 files changed, 524 insertions, 95 deletions

diff --git a/net/9p/Kconfig b/net/9p/Kconfig
index bafc50c9e6ff..ff34c5acc130 100644
--- a/net/9p/Kconfig
+++ b/net/9p/Kconfig
@@ -13,16 +13,6 @@ menuconfig NET_9P
 
 	  If unsure, say N.
 
-config NET_9P_FD
-	depends on NET_9P
-	default y if NET_9P
-	tristate "9P File Descriptor Transports (Experimental)"
-	help
-	  This builds support for file descriptor transports for 9p
-	  which includes support for TCP/IP, named pipes, or passed
-	  file descriptors.  TCP/IP is the default transport for 9p,
-	  so if you are going to use 9p, you'll likely want this.
-
 config NET_9P_VIRTIO
 	depends on NET_9P && EXPERIMENTAL && VIRTIO
 	tristate "9P Virtio Transport (Experimental)"
diff --git a/net/9p/Makefile b/net/9p/Makefile
index 8a1051101898..519219480db1 100644
--- a/net/9p/Makefile
+++ b/net/9p/Makefile
@@ -1,5 +1,4 @@
 obj-$(CONFIG_NET_9P) := 9pnet.o
-obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
 obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 
 9pnet-objs := \
@@ -9,8 +8,6 @@ obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 	error.o \
 	fcprint.o \
 	util.o \
-
-9pnet_fd-objs := \
 	trans_fd.o \
 
 9pnet_virtio-objs := \
diff --git a/net/9p/client.c b/net/9p/client.c
index 84e087e24146..2ffe40cf2f01 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -64,21 +64,30 @@ static match_table_t tokens = {
  * @options: options string passed from mount
  * @v9ses: existing v9fs session information
  *
+ * Return 0 upon success, -ERRNO upon failure
  */
 
-static void parse_opts(char *options, struct p9_client *clnt)
+static int parse_opts(char *opts, struct p9_client *clnt)
 {
+	char *options;
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int option;
-	int ret;
+	int ret = 0;
 
 	clnt->trans_mod = v9fs_default_trans();
 	clnt->dotu = 1;
 	clnt->msize = 8192;
 
-	if (!options)
-		return;
+	if (!opts)
+		return 0;
+
+	options = kstrdup(opts, GFP_KERNEL);
+	if (!options) {
+		P9_DPRINTK(P9_DEBUG_ERROR,
+				"failed to allocate copy of option string\n");
+		return -ENOMEM;
+	}
 
 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;
@@ -86,10 +95,11 @@ static void parse_opts(char *options, struct p9_client *clnt)
 			continue;
 		token = match_token(p, tokens, args);
 		if (token < Opt_trans) {
-			ret = match_int(&args[0], &option);
-			if (ret < 0) {
+			int r = match_int(&args[0], &option);
+			if (r < 0) {
 				P9_DPRINTK(P9_DEBUG_ERROR,
 					"integer field, but no integer?\n");
+				ret = r;
 				continue;
 			}
 		}
@@ -107,6 +117,8 @@ static void parse_opts(char *options, struct p9_client *clnt)
 			continue;
 		}
 	}
+	kfree(options);
+	return ret;
 }
 
 
@@ -138,16 +150,20 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 	if (!clnt)
 		return ERR_PTR(-ENOMEM);
 
+	clnt->trans = NULL;
 	spin_lock_init(&clnt->lock);
 	INIT_LIST_HEAD(&clnt->fidlist);
 	clnt->fidpool = p9_idpool_create();
-	if (!clnt->fidpool) {
+	if (IS_ERR(clnt->fidpool)) {
 		err = PTR_ERR(clnt->fidpool);
 		clnt->fidpool = NULL;
 		goto error;
 	}
 
-	parse_opts(options, clnt);
+	err = parse_opts(options, clnt);
+	if (err < 0)
+		goto error;
+
 	if (clnt->trans_mod == NULL) {
 		err = -EPROTONOSUPPORT;
 		P9_DPRINTK(P9_DEBUG_ERROR,
diff --git a/net/9p/conv.c b/net/9p/conv.c
index 3fe35d532c87..44547201f5bc 100644
--- a/net/9p/conv.c
+++ b/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);
+
diff --git a/net/9p/error.c b/net/9p/error.c
index 64104b9cb422..fdebe4314062 100644
--- a/net/9p/error.c
+++ b/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
  *
  */
 
@@ -230,8 +237,8 @@ int p9_errstr2errno(char *errstr, int len)
 	if (errno == 0) {
 		/* TODO: if error isn't found, add it dynamically */
 		errstr[len] = 0;
-		printk(KERN_ERR "%s: errstr :%s: not found\n", __func__,
-		       errstr);
+		printk(KERN_ERR "%s: server reported unknown error %s\n",
+			__func__, errstr);
 		errno = 1;
 	}
 
diff --git a/net/9p/fcprint.c b/net/9p/fcprint.c
index 40244fbd9b0d..53dd8e28dd8a 100644
--- a/net/9p/fcprint.c
+++ b/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)
 {
diff --git a/net/9p/mod.c b/net/9p/mod.c
index c285aab2af04..bdee1fb7cc62 100644
--- a/net/9p/mod.c
+++ b/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)
@@ -110,6 +107,7 @@ static int __init init_p9(void)
 
 	p9_error_init();
 	printk(KERN_INFO "Installing 9P2000 support\n");
+	p9_trans_fd_init();
 
 	return ret;
 }
diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
index f624dff76852..4507f744f44e 100644
--- a/net/9p/trans_fd.c
+++ b/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;
@@ -1097,35 +1196,46 @@ void p9_conn_cancel(struct p9_conn *m, int err)
 }
 
 /**
- * v9fs_parse_options - parse mount options into session structure
+ * 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
  *
+ * Returns 0 upon success, -ERRNO upon failure
  */
 
-static void parse_opts(char *options, struct p9_fd_opts *opts)
+static int parse_opts(char *params, struct p9_fd_opts *opts)
 {
 	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int option;
+	char *options;
 	int ret;
 
 	opts->port = P9_PORT;
 	opts->rfd = ~0;
 	opts->wfd = ~0;
 
-	if (!options)
-		return;
+	if (!params)
+		return 0;
+
+	options = kstrdup(params, GFP_KERNEL);
+	if (!options) {
+		P9_DPRINTK(P9_DEBUG_ERROR,
+				"failed to allocate copy of option string\n");
+		return -ENOMEM;
+	}
 
 	while ((p = strsep(&options, ",")) != NULL) {
 		int token;
+		int r;
 		if (!*p)
 			continue;
 		token = match_token(p, tokens, args);
-		ret = match_int(&args[0], &option);
-		if (ret < 0) {
+		r = match_int(&args[0], &option);
+		if (r < 0) {
 			P9_DPRINTK(P9_DEBUG_ERROR,
 			 "integer field, but no integer?\n");
+			ret = r;
 			continue;
 		}
 		switch (token) {
@@ -1142,6 +1252,8 @@ static void parse_opts(char *options, struct p9_fd_opts *opts)
 			continue;
 		}
 	}
+	kfree(options);
+	return 0;
 }
 
 static int p9_fd_open(struct p9_trans *trans, int rfd, int wfd)
@@ -1193,11 +1305,12 @@ 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 +1333,12 @@ 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 +1410,7 @@ end:
  * @trans: private socket structure
  *
  */
+
 static void p9_fd_close(struct p9_trans *trans)
 {
 	struct p9_trans_fd *ts;
@@ -1318,6 +1433,23 @@ static void p9_fd_close(struct p9_trans *trans)
 	kfree(ts);
 }
 
+/*
+ * stolen from NFS - maybe should be made a generic function?
+ */
+static inline int valid_ipaddr4(const char *buf)
+{
+	int rc, count, in[4];
+
+	rc = sscanf(buf, "%d.%d.%d.%d", &in[0], &in[1], &in[2], &in[3]);
+	if (rc != 4)
+		return -EINVAL;
+	for (count = 0; count < 4; count++) {
+		if (in[count] > 255)
+			return -EINVAL;
+	}
+	return 0;
+}
+
 static struct p9_trans *
 p9_trans_create_tcp(const char *addr, char *args, int msize, unsigned char dotu)
 {
@@ -1328,7 +1460,12 @@ p9_trans_create_tcp(const char *addr, char *args, int msize, unsigned char dotu)
 	struct p9_fd_opts opts;
 	struct p9_trans_fd *p;
 
-	parse_opts(args, &opts);
+	err = parse_opts(args, &opts);
+	if (err < 0)
+		return ERR_PTR(err);
+
+	if (valid_ipaddr4(addr) < 0)
+		return ERR_PTR(-EINVAL);
 
 	csocket = NULL;
 	trans = kmalloc(sizeof(struct p9_trans), GFP_KERNEL);
@@ -1508,7 +1645,7 @@ static struct p9_trans_module p9_fd_trans = {
 	.create = p9_trans_create_fd,
 };
 
-static int __init p9_trans_fd_init(void)
+int p9_trans_fd_init(void)
 {
 	int ret = p9_mux_global_init();
 	if (ret) {
@@ -1522,9 +1659,4 @@ static int __init p9_trans_fd_init(void)
 
 	return 0;
 }
-
-module_init(p9_trans_fd_init);
-
-MODULE_AUTHOR("Latchesar Ionkov <lucho@ionkov.net>");
-MODULE_AUTHOR("Eric Van Hensbergen <ericvh@gmail.com>");
-MODULE_LICENSE("GPL");
+EXPORT_SYMBOL(p9_trans_fd_init);
diff --git a/net/9p/trans_virtio.c b/net/9p/trans_virtio.c
index de7a9f532edc..42adc052b149 100644
--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -49,29 +49,75 @@
 #define VIRTQUEUE_NUM	128
 
 /* a single mutex to manage channel initialization and attachment */
-static DECLARE_MUTEX(virtio_9p_lock);
+static DEFINE_MUTEX(virtio_9p_lock);
 /* global which tracks highest initialized channel */
 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
@@ -130,11 +188,20 @@ 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;
 	int count;
-	unsigned int flags;
+	unsigned long flags;
 
 	spin_lock_irqsave(&chan->lock, flags);
 	p9_idpool_destroy(chan->tagpool);
@@ -144,13 +211,26 @@ static void p9_virtio_close(struct p9_trans *trans)
 	chan->max_tag = 0;
 	spin_unlock_irqrestore(&chan->lock, flags);
 
-	down(&virtio_9p_lock);
+	mutex_lock(&virtio_9p_lock);
 	chan->inuse = false;
-	up(&virtio_9p_lock);
+	mutex_unlock(&virtio_9p_lock);
 
 	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)
 {
@@ -263,16 +365,26 @@ 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;
 	struct virtio_chan *chan;
 	int index;
 
-	down(&virtio_9p_lock);
+	mutex_lock(&virtio_9p_lock);
 	index = chan_index++;
 	chan = &channels[index];
-	up(&virtio_9p_lock);
+	mutex_unlock(&virtio_9p_lock);
 
 	if (chan_index > MAX_9P_CHAN) {
 		printk(KERN_ERR "9p: virtio: Maximum channels exceeded\n");
@@ -301,17 +413,34 @@ static int p9_virtio_probe(struct virtio_device *vdev)
 out_free_vq:
 	vdev->config->del_vq(chan->vq);
 fail:
-	down(&virtio_9p_lock);
+	mutex_lock(&virtio_9p_lock);
 	chan_index--;
-	up(&virtio_9p_lock);
+	mutex_unlock(&virtio_9p_lock);
 	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)
@@ -320,7 +449,7 @@ p9_virtio_create(const char *devname, char *args, int msize,
 	struct virtio_chan *chan = channels;
 	int index = 0;
 
-	down(&virtio_9p_lock);
+	mutex_lock(&virtio_9p_lock);
 	while (index < MAX_9P_CHAN) {
 		if (chan->initialized && !chan->inuse) {
 			chan->inuse = true;
@@ -330,7 +459,7 @@ p9_virtio_create(const char *devname, char *args, int msize,
 			chan = &channels[index];
 		}
 	}
-	up(&virtio_9p_lock);
+	mutex_unlock(&virtio_9p_lock);
 
 	if (index >= MAX_9P_CHAN) {
 		printk(KERN_ERR "9p: no channels available\n");
@@ -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;
diff --git a/net/9p/util.c b/net/9p/util.c
index ef7215565d88..958fc58cd1ff 100644
--- a/net/9p/util.c
+++ b/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?
  */
 
@@ -71,7 +88,7 @@ int p9_idpool_get(struct p9_idpool *p)
 {
 	int i = 0;
 	int error;
-	unsigned int flags;
+	unsigned long flags;
 
 retry:
 	if (idr_pre_get(&p->pool, GFP_KERNEL) == 0)
@@ -94,15 +111,16 @@ 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?
  */
 
 void p9_idpool_put(int id, struct p9_idpool *p)
 {
-	unsigned int flags;
+	unsigned long flags;
 	spin_lock_irqsave(&p->lock, flags);
 	idr_remove(&p->pool, id);
 	spin_unlock_irqrestore(&p->lock, flags);
@@ -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);
+