Merge branch 'for-linus' of git://github.com/ericvh/linux

* 'for-linus' of git://github.com/ericvh/linux:
  9p: fix 9p.txt to advertise msize instead of maxdata
  net/9p: Convert net/9p protocol dumps to tracepoints
  fs/9p: change an int to unsigned int
  fs/9p: Cleanup option parsing in 9p
  9p: move dereference after NULL check
  fs/9p: inode file operation is properly initialized init_special_inode
  fs/9p: Update zero-copy implementation in 9p

14 files changed, 772 insertions, 452 deletions

diff --git a/Documentation/filesystems/9p.txt b/Documentation/filesystems/9p.txt
index 13de64c7f0a..2c032144284 100644
--- a/Documentation/filesystems/9p.txt
+++ b/Documentation/filesystems/9p.txt
@@ -92,7 +92,7 @@ OPTIONS
 
   wfdno=n	the file descriptor for writing with trans=fd
 
-  maxdata=n	the number of bytes to use for 9p packet payload (msize)
+  msize=n	the number of bytes to use for 9p packet payload
 
   port=n	port to connect to on the remote server
 
diff --git a/fs/9p/v9fs.c b/fs/9p/v9fs.c
index ef966188611..2b78014a124 100644
--- a/fs/9p/v9fs.c
+++ b/fs/9p/v9fs.c
@@ -132,21 +132,19 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 	options = tmp_options;
 
 	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
+		int token, r;
 		if (!*p)
 			continue;
 		token = match_token(p, tokens, args);
-		if (token < Opt_uname) {
-			int r = match_int(&args[0], &option);
+		switch (token) {
+		case Opt_debug:
+			r = match_int(&args[0], &option);
 			if (r < 0) {
 				P9_DPRINTK(P9_DEBUG_ERROR,
-					"integer field, but no integer?\n");
+					   "integer field, but no integer?\n");
 				ret = r;
 				continue;
 			}
-		}
-		switch (token) {
-		case Opt_debug:
 			v9ses->debug = option;
 #ifdef CONFIG_NET_9P_DEBUG
 			p9_debug_level = option;
@@ -154,12 +152,33 @@ static int v9fs_parse_options(struct v9fs_session_info *v9ses, char *opts)
 			break;
 
 		case Opt_dfltuid:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				P9_DPRINTK(P9_DEBUG_ERROR,
+					   "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
 			v9ses->dfltuid = option;
 			break;
 		case Opt_dfltgid:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				P9_DPRINTK(P9_DEBUG_ERROR,
+					   "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
 			v9ses->dfltgid = option;
 			break;
 		case Opt_afid:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				P9_DPRINTK(P9_DEBUG_ERROR,
+					   "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
 			v9ses->afid = option;
 			break;
 		case Opt_uname:
diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
index 9c2bdda5cd9..598fff1a54e 100644
--- a/fs/9p/vfs_dir.c
+++ b/fs/9p/vfs_dir.c
@@ -165,9 +165,8 @@ static int v9fs_dir_readdir(struct file *filp, void *dirent, filldir_t filldir)
 		}
 		while (rdir->head < rdir->tail) {
 			p9stat_init(&st);
-			err = p9stat_read(rdir->buf + rdir->head,
-						rdir->tail - rdir->head, &st,
-						fid->clnt->proto_version);
+			err = p9stat_read(fid->clnt, rdir->buf + rdir->head,
+					  rdir->tail - rdir->head, &st);
 			if (err) {
 				P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
 				err = -EIO;
@@ -231,7 +230,7 @@ static int v9fs_dir_readdir_dotl(struct file *filp, void *dirent,
 	while (err == 0) {
 		if (rdir->tail == rdir->head) {
 			err = p9_client_readdir(fid, rdir->buf, buflen,
-								filp->f_pos);
+						filp->f_pos);
 			if (err <= 0)
 				goto unlock_and_exit;
 
@@ -241,10 +240,9 @@ static int v9fs_dir_readdir_dotl(struct file *filp, void *dirent,
 
 		while (rdir->head < rdir->tail) {
 
-			err = p9dirent_read(rdir->buf + rdir->head,
-						rdir->tail - rdir->head,
-						&curdirent,
-						fid->clnt->proto_version);
+			err = p9dirent_read(fid->clnt, rdir->buf + rdir->head,
+					    rdir->tail - rdir->head,
+					    &curdirent);
 			if (err < 0) {
 				P9_DPRINTK(P9_DEBUG_VFS, "returned %d\n", err);
 				err = -EIO;
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index e3c03db3c78..b5a1076aaa6 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -278,10 +278,8 @@ int v9fs_init_inode(struct v9fs_session_info *v9ses,
 	case S_IFSOCK:
 		if (v9fs_proto_dotl(v9ses)) {
 			inode->i_op = &v9fs_file_inode_operations_dotl;
-			inode->i_fop = &v9fs_file_operations_dotl;
 		} else if (v9fs_proto_dotu(v9ses)) {
 			inode->i_op = &v9fs_file_inode_operations;
-			inode->i_fop = &v9fs_file_operations;
 		} else {
 			P9_DPRINTK(P9_DEBUG_ERROR,
 				   "special files without extended mode\n");
diff --git a/include/net/9p/9p.h b/include/net/9p/9p.h
index a6326ef8ade..2d70b95b3b5 100644
--- a/include/net/9p/9p.h
+++ b/include/net/9p/9p.h
@@ -76,11 +76,8 @@ do {  \
 	} \
 } while (0)
 
-#define P9_DUMP_PKT(way, pdu) p9pdu_dump(way, pdu)
-
 #else
 #define P9_DPRINTK(level, format, arg...)  do { } while (0)
-#define P9_DUMP_PKT(way, pdu) do { } while (0)
 #endif
 
 
@@ -359,6 +356,9 @@ enum p9_qid_t {
 /* Room for readdir header */
 #define P9_READDIRHDRSZ	24
 
+/* size of header for zero copy read/write */
+#define P9_ZC_HDR_SZ 4096
+
 /**
  * struct p9_qid - file system entity information
  * @type: 8-bit type &p9_qid_t
@@ -555,10 +555,6 @@ struct p9_rstatfs {
  * @tag: transaction id of the request
  * @offset: used by marshalling routines to track current position in buffer
  * @capacity: used by marshalling routines to track total malloc'd capacity
- * @pubuf: Payload user buffer given by the caller
- * @pkbuf: Payload kernel buffer given by the caller
- * @pbuf_size: pubuf/pkbuf(only one will be !NULL) size to be read/write.
- * @private: For transport layer's use.
  * @sdata: payload
  *
  * &p9_fcall represents the structure for all 9P RPC
@@ -575,10 +571,6 @@ struct p9_fcall {
 
 	size_t offset;
 	size_t capacity;
-	char __user *pubuf;
-	char *pkbuf;
-	size_t pbuf_size;
-	void *private;
 
 	u8 *sdata;
 };
diff --git a/include/net/9p/client.h b/include/net/9p/client.h
index 55ce72ce986..fc9b90b0c05 100644
--- a/include/net/9p/client.h
+++ b/include/net/9p/client.h
@@ -151,7 +151,7 @@ struct p9_req_t {
 
 struct p9_client {
 	spinlock_t lock; /* protect client structure */
-	int msize;
+	unsigned int msize;
 	unsigned char proto_version;
 	struct p9_trans_module *trans_mod;
 	enum p9_trans_status status;
@@ -240,8 +240,8 @@ int p9_client_read(struct p9_fid *fid, char *data, char __user *udata,
 int p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
 							u64 offset, u32 count);
 int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset);
-int p9dirent_read(char *buf, int len, struct p9_dirent *dirent,
-							int proto_version);
+int p9dirent_read(struct p9_client *clnt, char *buf, int len,
+		  struct p9_dirent *dirent);
 struct p9_wstat *p9_client_stat(struct p9_fid *fid);
 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst);
 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *attr);
@@ -259,7 +259,7 @@ struct p9_req_t *p9_tag_lookup(struct p9_client *, u16);
 void p9_client_cb(struct p9_client *c, struct p9_req_t *req);
 
 int p9_parse_header(struct p9_fcall *, int32_t *, int8_t *, int16_t *, int);
-int p9stat_read(char *, int, struct p9_wstat *, int);
+int p9stat_read(struct p9_client *, char *, int, struct p9_wstat *);
 void p9stat_free(struct p9_wstat *);
 
 int p9_is_proto_dotu(struct p9_client *clnt);
diff --git a/include/net/9p/transport.h b/include/net/9p/transport.h
index 83531ebeee9..adcbb20f651 100644
--- a/include/net/9p/transport.h
+++ b/include/net/9p/transport.h
@@ -26,13 +26,6 @@
 #ifndef NET_9P_TRANSPORT_H
 #define NET_9P_TRANSPORT_H
 
-#define P9_TRANS_PREF_PAYLOAD_MASK 0x1
-
-/* Default. Add Payload to PDU before sending it down to transport layer */
-#define P9_TRANS_PREF_PAYLOAD_DEF  0x0
-/* Send pay load separately to transport layer along with PDU.*/
-#define P9_TRANS_PREF_PAYLOAD_SEP  0x1
-
 /**
  * struct p9_trans_module - transport module interface
  * @list: used to maintain a list of currently available transports
@@ -56,13 +49,14 @@ struct p9_trans_module {
 	struct list_head list;
 	char *name;		/* name of transport */
 	int maxsize;		/* max message size of transport */
-	int pref;               /* Preferences of this transport */
 	int def;		/* this transport should be default */
 	struct module *owner;
 	int (*create)(struct p9_client *, const char *, char *);
 	void (*close) (struct p9_client *);
 	int (*request) (struct p9_client *, struct p9_req_t *req);
 	int (*cancel) (struct p9_client *, struct p9_req_t *req);
+	int (*zc_request)(struct p9_client *, struct p9_req_t *,
+			  char *, char *, int , int, int, int);
 };
 
 void v9fs_register_trans(struct p9_trans_module *m);
diff --git a/include/trace/events/9p.h b/include/trace/events/9p.h
new file mode 100644
index 00000000000..beeaed8398e
--- /dev/null
+++ b/include/trace/events/9p.h
@@ -0,0 +1,176 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM 9p
+
+#if !defined(_TRACE_9P_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_9P_H
+
+#include <linux/tracepoint.h>
+
+#define show_9p_op(type)						\
+	__print_symbolic(type,						\
+			 { P9_TLERROR,		"P9_TLERROR" },		\
+			 { P9_RLERROR,		"P9_RLERROR" },		\
+			 { P9_TSTATFS,		"P9_TSTATFS" },		\
+			 { P9_RSTATFS,		"P9_RSTATFS" },		\
+			 { P9_TLOPEN,		"P9_TLOPEN" },		\
+			 { P9_RLOPEN,		"P9_RLOPEN" },		\
+			 { P9_TLCREATE,		"P9_TLCREATE" },	\
+			 { P9_RLCREATE,		"P9_RLCREATE" },	\
+			 { P9_TSYMLINK,		"P9_TSYMLINK" },	\
+			 { P9_RSYMLINK,		"P9_RSYMLINK" },	\
+			 { P9_TMKNOD,		"P9_TMKNOD" },		\
+			 { P9_RMKNOD,		"P9_RMKNOD" },		\
+			 { P9_TRENAME,		"P9_TRENAME" },		\
+			 { P9_RRENAME,		"P9_RRENAME" },		\
+			 { P9_TREADLINK,	"P9_TREADLINK" },	\
+			 { P9_RREADLINK,	"P9_RREADLINK" },	\
+			 { P9_TGETATTR,		"P9_TGETATTR" },	\
+			 { P9_RGETATTR,		"P9_RGETATTR" },	\
+			 { P9_TSETATTR,		"P9_TSETATTR" },	\
+			 { P9_RSETATTR,		"P9_RSETATTR" },	\
+			 { P9_TXATTRWALK,	"P9_TXATTRWALK" },	\
+			 { P9_RXATTRWALK,	"P9_RXATTRWALK" },	\
+			 { P9_TXATTRCREATE,	"P9_TXATTRCREATE" },	\
+			 { P9_RXATTRCREATE,	"P9_RXATTRCREATE" },	\
+			 { P9_TREADDIR,		"P9_TREADDIR" },	\
+			 { P9_RREADDIR,		"P9_RREADDIR" },	\
+			 { P9_TFSYNC,		"P9_TFSYNC" },		\
+			 { P9_RFSYNC,		"P9_RFSYNC" },		\
+			 { P9_TLOCK,		"P9_TLOCK" },		\
+			 { P9_RLOCK,		"P9_RLOCK" },		\
+			 { P9_TGETLOCK,		"P9_TGETLOCK" },	\
+			 { P9_RGETLOCK,		"P9_RGETLOCK" },	\
+			 { P9_TLINK,		"P9_TLINK" },		\
+			 { P9_RLINK,		"P9_RLINK" },		\
+			 { P9_TMKDIR,		"P9_TMKDIR" },		\
+			 { P9_RMKDIR,		"P9_RMKDIR" },		\
+			 { P9_TRENAMEAT,	"P9_TRENAMEAT" },	\
+			 { P9_RRENAMEAT,	"P9_RRENAMEAT" },	\
+			 { P9_TUNLINKAT,	"P9_TUNLINKAT" },	\
+			 { P9_RUNLINKAT,	"P9_RUNLINKAT" },	\
+			 { P9_TVERSION,		"P9_TVERSION" },	\
+			 { P9_RVERSION,		"P9_RVERSION" },	\
+			 { P9_TAUTH,		"P9_TAUTH" },		\
+			 { P9_RAUTH,		"P9_RAUTH" },		\
+			 { P9_TATTACH,		"P9_TATTACH" },		\
+			 { P9_RATTACH,		"P9_RATTACH" },		\
+			 { P9_TERROR,		"P9_TERROR" },		\
+			 { P9_RERROR,		"P9_RERROR" },		\
+			 { P9_TFLUSH,		"P9_TFLUSH" },		\
+			 { P9_RFLUSH,		"P9_RFLUSH" },		\
+			 { P9_TWALK,		"P9_TWALK" },		\
+			 { P9_RWALK,		"P9_RWALK" },		\
+			 { P9_TOPEN,		"P9_TOPEN" },		\
+			 { P9_ROPEN,		"P9_ROPEN" },		\
+			 { P9_TCREATE,		"P9_TCREATE" },		\
+			 { P9_RCREATE,		"P9_RCREATE" },		\
+			 { P9_TREAD,		"P9_TREAD" },		\
+			 { P9_RREAD,		"P9_RREAD" },		\
+			 { P9_TWRITE,		"P9_TWRITE" },		\
+			 { P9_RWRITE,		"P9_RWRITE" },		\
+			 { P9_TCLUNK,		"P9_TCLUNK" },		\
+			 { P9_RCLUNK,		"P9_RCLUNK" },		\
+			 { P9_TREMOVE,		"P9_TREMOVE" },		\
+			 { P9_RREMOVE,		"P9_RREMOVE" },		\
+			 { P9_TSTAT,		"P9_TSTAT" },		\
+			 { P9_RSTAT,		"P9_RSTAT" },		\
+			 { P9_TWSTAT,		"P9_TWSTAT" },		\
+			 { P9_RWSTAT,		"P9_RWSTAT" })
+
+TRACE_EVENT(9p_client_req,
+	    TP_PROTO(struct p9_client *clnt, int8_t type, int tag),
+
+	    TP_ARGS(clnt, type, tag),
+
+	    TP_STRUCT__entry(
+		    __field(    void *,		clnt			     )
+		    __field(	__u8,		type			     )
+		    __field(	__u32,		tag			     )
+		    ),
+
+	    TP_fast_assign(
+		    __entry->clnt    =  clnt;
+		    __entry->type    =  type;
+		    __entry->tag     =  tag;
+		    ),
+
+	    TP_printk("client %lu request %s tag  %d",
+		    (long)__entry->clnt, show_9p_op(__entry->type),
+		    __entry->tag)
+ );
+
+TRACE_EVENT(9p_client_res,
+	    TP_PROTO(struct p9_client *clnt, int8_t type, int tag, int err),
+
+	    TP_ARGS(clnt, type, tag, err),
+
+	    TP_STRUCT__entry(
+		    __field(    void *,		clnt			     )
+		    __field(	__u8,		type			     )
+		    __field(	__u32,		tag			     )
+		    __field(	__u32,		err			     )
+		    ),
+
+	    TP_fast_assign(
+		    __entry->clnt    =  clnt;
+		    __entry->type    =  type;
+		    __entry->tag     =  tag;
+		    __entry->err     =  err;
+		    ),
+
+	    TP_printk("client %lu response %s tag  %d err %d",
+		      (long)__entry->clnt, show_9p_op(__entry->type),
+		      __entry->tag, __entry->err)
+);
+
+/* dump 32 bytes of protocol data */
+#define P9_PROTO_DUMP_SZ 32
+TRACE_EVENT(9p_protocol_dump,
+	    TP_PROTO(struct p9_client *clnt, struct p9_fcall *pdu),
+
+	    TP_ARGS(clnt, pdu),
+
+	    TP_STRUCT__entry(
+		    __field(	void *,		clnt				)
+		    __field(	__u8,		type				)
+		    __field(	__u16,		tag				)
+		    __array(	unsigned char,	line,	P9_PROTO_DUMP_SZ	)
+		    ),
+
+	    TP_fast_assign(
+		    __entry->clnt   =  clnt;
+		    __entry->type   =  pdu->id;
+		    __entry->tag    =  pdu->tag;
+		    memcpy(__entry->line, pdu->sdata, P9_PROTO_DUMP_SZ);
+		    ),
+	    TP_printk("clnt %lu %s(tag = %d)\n%.3x: "
+		      "%02x %02x %02x %02x %02x %02x %02x %02x "
+		      "%02x %02x %02x %02x %02x %02x %02x %02x\n"
+		      "%.3x: "
+		      "%02x %02x %02x %02x %02x %02x %02x %02x "
+		      "%02x %02x %02x %02x %02x %02x %02x %02x\n",
+		      (long)__entry->clnt, show_9p_op(__entry->type),
+		      __entry->tag, 0,
+		      __entry->line[0],  __entry->line[1],
+		      __entry->line[2],  __entry->line[3],
+		      __entry->line[4],  __entry->line[5],
+		      __entry->line[6],  __entry->line[7],
+		      __entry->line[8],  __entry->line[9],
+		      __entry->line[10], __entry->line[11],
+		      __entry->line[12], __entry->line[13],
+		      __entry->line[14], __entry->line[15],
+		      16,
+		      __entry->line[16], __entry->line[17],
+		      __entry->line[18], __entry->line[19],
+		      __entry->line[20], __entry->line[21],
+		      __entry->line[22], __entry->line[23],
+		      __entry->line[24], __entry->line[25],
+		      __entry->line[26], __entry->line[27],
+		      __entry->line[28], __entry->line[29],
+		      __entry->line[30], __entry->line[31])
+ );
+
+#endif /* _TRACE_9P_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/net/9p/client.c b/net/9p/client.c
index 0505a03c374..854ca7a911c 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -38,6 +38,9 @@
 #include <net/9p/transport.h>
 #include "protocol.h"
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/9p.h>
+
 /*
   * Client Option Parsing (code inspired by NFS code)
   *  - a little lazy - parse all client options
@@ -123,21 +126,19 @@ static int parse_opts(char *opts, struct p9_client *clnt)
 	options = tmp_options;
 
 	while ((p = strsep(&options, ",")) != NULL) {
-		int token;
+		int token, r;
 		if (!*p)
 			continue;
 		token = match_token(p, tokens, args);
-		if (token < Opt_trans) {
-			int r = match_int(&args[0], &option);
+		switch (token) {
+		case Opt_msize:
+			r = match_int(&args[0], &option);
 			if (r < 0) {
 				P9_DPRINTK(P9_DEBUG_ERROR,
-					"integer field, but no integer?\n");
+					   "integer field, but no integer?\n");
 				ret = r;
 				continue;
 			}
-		}
-		switch (token) {
-		case Opt_msize:
 			clnt->msize = option;
 			break;
 		case Opt_trans:
@@ -203,11 +204,13 @@ free_and_return:
  *
  */
 
-static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
+static struct p9_req_t *
+p9_tag_alloc(struct p9_client *c, u16 tag, unsigned int max_size)
 {
 	unsigned long flags;
 	int row, col;
 	struct p9_req_t *req;
+	int alloc_msize = min(c->msize, max_size);
 
 	/* This looks up the original request by tag so we know which
 	 * buffer to read the data into */
@@ -245,23 +248,10 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
 			return ERR_PTR(-ENOMEM);
 		}
 		init_waitqueue_head(req->wq);
-		if ((c->trans_mod->pref & P9_TRANS_PREF_PAYLOAD_MASK) ==
-				P9_TRANS_PREF_PAYLOAD_SEP) {
-			int alloc_msize = min(c->msize, 4096);
-			req->tc = kmalloc(sizeof(struct p9_fcall)+alloc_msize,
-					  GFP_NOFS);
-			req->tc->capacity = alloc_msize;
-			req->rc = kmalloc(sizeof(struct p9_fcall)+alloc_msize,
-					  GFP_NOFS);
-			req->rc->capacity = alloc_msize;
-		} else {
-			req->tc = kmalloc(sizeof(struct p9_fcall)+c->msize,
-					  GFP_NOFS);
-			req->tc->capacity = c->msize;
-			req->rc = kmalloc(sizeof(struct p9_fcall)+c->msize,
-					  GFP_NOFS);
-			req->rc->capacity = c->msize;
-		}
+		req->tc = kmalloc(sizeof(struct p9_fcall) + alloc_msize,
+				  GFP_NOFS);
+		req->rc = kmalloc(sizeof(struct p9_fcall) + alloc_msize,
+				  GFP_NOFS);
 		if ((!req->tc) || (!req->rc)) {
 			printk(KERN_ERR "Couldn't grow tag array\n");
 			kfree(req->tc);
@@ -271,6 +261,8 @@ static struct p9_req_t *p9_tag_alloc(struct p9_client *c, u16 tag)
 			req->wq = NULL;
 			return ERR_PTR(-ENOMEM);
 		}
+		req->tc->capacity = alloc_msize;
+		req->rc->capacity = alloc_msize;
 		req->tc->sdata = (char *) req->tc + sizeof(struct p9_fcall);
 		req->rc->sdata = (char *) req->rc + sizeof(struct p9_fcall);
 	}
@@ -475,37 +467,22 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 	int ecode;
 
 	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
+	/*
+	 * dump the response from server
+	 * This should be after check errors which poplulate pdu_fcall.
+	 */
+	trace_9p_protocol_dump(c, req->rc);
 	if (err) {
 		P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
 		return err;
 	}
-
 	if (type != P9_RERROR && type != P9_RLERROR)
 		return 0;
 
 	if (!p9_is_proto_dotl(c)) {
 		char *ename;
-
-		if (req->tc->pbuf_size) {
-			/* Handle user buffers */
-			size_t len = req->rc->size - req->rc->offset;
-			if (req->tc->pubuf) {
-				/* User Buffer */
-				err = copy_from_user(
-					&req->rc->sdata[req->rc->offset],
-					req->tc->pubuf, len);
-				if (err) {
-					err = -EFAULT;
-					goto out_err;
-				}
-			} else {
-				/* Kernel Buffer */
-				memmove(&req->rc->sdata[req->rc->offset],
-						req->tc->pkbuf, len);
-			}
-		}
 		err = p9pdu_readf(req->rc, c->proto_version, "s?d",
-				&ename, &ecode);
+				  &ename, &ecode);
 		if (err)
 			goto out_err;
 
@@ -515,11 +492,10 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 		if (!err || !IS_ERR_VALUE(err)) {
 			err = p9_errstr2errno(ename, strlen(ename));
 
-			P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n", -ecode,
-					ename);
-
-			kfree(ename);
+			P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
+				   -ecode, ename);
 		}
+		kfree(ename);
 	} else {
 		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
 		err = -ecode;
@@ -527,7 +503,6 @@ static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
 		P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
 	}
 
-
 	return err;
 
 out_err:
@@ -536,6 +511,115 @@ out_err:
 	return err;
 }
 
+/**
+ * p9_check_zc_errors - check 9p packet for error return and process it
+ * @c: current client instance
+ * @req: request to parse and check for error conditions
+ * @in_hdrlen: Size of response protocol buffer.
+ *
+ * returns error code if one is discovered, otherwise returns 0
+ *
+ * this will have to be more complicated if we have multiple
+ * error packet types
+ */
+
+static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
+			      char *uidata, int in_hdrlen, int kern_buf)
+{
+	int err;
+	int ecode;
+	int8_t type;
+	char *ename = NULL;
+
+	err = p9_parse_header(req->rc, NULL, &type, NULL, 0);
+	/*
+	 * dump the response from server
+	 * This should be after parse_header which poplulate pdu_fcall.
+	 */
+	trace_9p_protocol_dump(c, req->rc);
+	if (err) {
+		P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
+		return err;
+	}
+
+	if (type != P9_RERROR && type != P9_RLERROR)
+		return 0;
+
+	if (!p9_is_proto_dotl(c)) {
+		/* Error is reported in string format */
+		uint16_t len;
+		/* 7 = header size for RERROR, 2 is the size of string len; */
+		int inline_len = in_hdrlen - (7 + 2);
+
+		/* Read the size of error string */
+		err = p9pdu_readf(req->rc, c->proto_version, "w", &len);
+		if (err)
+			goto out_err;
+
+		ename = kmalloc(len + 1, GFP_NOFS);
+		if (!ename) {
+			err = -ENOMEM;
+			goto out_err;
+		}
+		if (len <= inline_len) {
+			/* We have error in protocol buffer itself */
+			if (pdu_read(req->rc, ename, len)) {
+				err = -EFAULT;
+				goto out_free;
+
+			}
+		} else {
+			/*
+			 *  Part of the data is in user space buffer.
+			 */
+			if (pdu_read(req->rc, ename, inline_len)) {
+				err = -EFAULT;
+				goto out_free;
+
+			}
+			if (kern_buf) {
+				memcpy(ename + inline_len, uidata,
+				       len - inline_len);
+			} else {
+				err = copy_from_user(ename + inline_len,
+						     uidata, len - inline_len);
+				if (err) {
+					err = -EFAULT;
+					goto out_free;
+				}
+			}
+		}
+		ename[len] = 0;
+		if (p9_is_proto_dotu(c)) {
+			/* For dotu we also have error code */
+			err = p9pdu_readf(req->rc,
+					  c->proto_version, "d", &ecode);
+			if (err)
+				goto out_free;
+			err = -ecode;
+		}
+		if (!err || !IS_ERR_VALUE(err)) {
+			err = p9_errstr2errno(ename, strlen(ename));
+
+			P9_DPRINTK(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
+				   -ecode, ename);
+		}
+		kfree(ename);
+	} else {
+		err = p9pdu_readf(req->rc, c->proto_version, "d", &ecode);
+		err = -ecode;
+
+		P9_DPRINTK(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
+	}
+	return err;
+
+out_free:
+	kfree(ename);
+out_err:
+	P9_DPRINTK(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
+	return err;
+}
+
 static struct p9_req_t *
 p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
 
@@ -579,23 +663,12 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
 	return 0;
 }
 
-/**
- * p9_client_rpc - issue a request and wait for a response
- * @c: client session
- * @type: type of request
- * @fmt: protocol format string (see protocol.c)
- *
- * Returns request structure (which client must free using p9_free_req)
- */
-
-static struct p9_req_t *
-p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
+static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
+					      int8_t type, int req_size,
+					      const char *fmt, va_list ap)
 {
-	va_list ap;
 	int tag, err;
 	struct p9_req_t *req;
-	unsigned long flags;
-	int sigpending;
 
 	P9_DPRINTK(P9_DEBUG_MUX, "client %p op %d\n", c, type);
 
@@ -607,12 +680,6 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 	if ((c->status == BeginDisconnect) && (type != P9_TCLUNK))
 		return ERR_PTR(-EIO);
 
-	if (signal_pending(current)) {
-		sigpending = 1;
-		clear_thread_flag(TIF_SIGPENDING);
-	} else
-		sigpending = 0;
-
 	tag = P9_NOTAG;
 	if (type != P9_TVERSION) {
 		tag = p9_idpool_get(c->tagpool);
@@ -620,18 +687,51 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 			return ERR_PTR(-ENOMEM);
 	}
 
-	req = p9_tag_alloc(c, tag);
+	req = p9_tag_alloc(c, tag, req_size);
 	if (IS_ERR(req))
 		return req;
 
 	/* marshall the data */
 	p9pdu_prepare(req->tc, tag, type);
-	va_start(ap, fmt);
 	err = p9pdu_vwritef(req->tc, c->proto_version, fmt, ap);
-	va_end(ap);
 	if (err)
 		goto reterr;
-	p9pdu_finalize(req->tc);
+	p9pdu_finalize(c, req->tc);
+	trace_9p_client_req(c, type, tag);
+	return req;
+reterr:
+	p9_free_req(c, req);
+	return ERR_PTR(err);
+}
+
+/**
+ * p9_client_rpc - issue a request and wait for a response
+ * @c: client session
+ * @type: type of request
+ * @fmt: protocol format string (see protocol.c)
+ *
+ * Returns request structure (which client must free using p9_free_req)
+ */
+
+static struct p9_req_t *
+p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
+{
+	va_list ap;
+	int sigpending, err;
+	unsigned long flags;
+	struct p9_req_t *req;
+
+	va_start(ap, fmt);
+	req = p9_client_prepare_req(c, type, c->msize, fmt, ap);
+	va_end(ap);
+	if (IS_ERR(req))
+		return req;
+
+	if (signal_pending(current)) {
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+	} else
+		sigpending = 0;
 
 	err = c->trans_mod->request(c, req);
 	if (err < 0) {
@@ -639,18 +739,14 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 			c->status = Disconnected;
 		goto reterr;
 	}
-
-	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d\n", req->wq, tag);
+	/* Wait for the response */
 	err = wait_event_interruptible(*req->wq,
-						req->status >= REQ_STATUS_RCVD);
-	P9_DPRINTK(P9_DEBUG_MUX, "wait %p tag: %d returned %d\n",
-						req->wq, tag, err);
+				       req->status >= REQ_STATUS_RCVD);
 
 	if (req->status == REQ_STATUS_ERROR) {
 		P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
 		err = req->t_err;
 	}
-
 	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
 		P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
 		sigpending = 1;
@@ -663,25 +759,102 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 		if (req->status == REQ_STATUS_RCVD)
 			err = 0;
 	}
-
 	if (sigpending) {
 		spin_lock_irqsave(&current->sighand->siglock, flags);
 		recalc_sigpending();
 		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	}
-
 	if (err < 0)
 		goto reterr;
 
 	err = p9_check_errors(c, req);
-	if (!err) {
-		P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d\n", c, type);
+	trace_9p_client_res(c, type, req->rc->tag, err);
+	if (!err)
+		return req;
+reterr:
+	p9_free_req(c, req);
+	return ERR_PTR(err);
+}
+
+/**
+ * p9_client_zc_rpc - issue a request and wait for a response
+ * @c: client session
+ * @type: type of request
+ * @uidata: user bffer that should be ued for zero copy read
+ * @uodata: user buffer that shoud be user for zero copy write
+ * @inlen: read buffer size
+ * @olen: write buffer size
+ * @hdrlen: reader header size, This is the size of response protocol data
+ * @fmt: protocol format string (see protocol.c)
+ *
+ * Returns request structure (which client must free using p9_free_req)
+ */
+static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
+					 char *uidata, char *uodata,
+					 int inlen, int olen, int in_hdrlen,
+					 int kern_buf, const char *fmt, ...)
+{
+	va_list ap;
+	int sigpending, err;
+	unsigned long flags;
+	struct p9_req_t *req;
+
+	va_start(ap, fmt);
+	/*
+	 * We allocate a inline protocol data of only 4k bytes.
+	 * The actual content is passed in zero-copy fashion.
+	 */
+	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, fmt, ap);
+	va_end(ap);
+	if (IS_ERR(req))
 		return req;
+
+	if (signal_pending(current)) {
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+	} else
+		sigpending = 0;
+
+	/* If we are called with KERNEL_DS force kern_buf */
+	if (segment_eq(get_fs(), KERNEL_DS))
+		kern_buf = 1;
+
+	err = c->trans_mod->zc_request(c, req, uidata, uodata,
+				       inlen, olen, in_hdrlen, kern_buf);
+	if (err < 0) {
+		if (err == -EIO)
+			c->status = Disconnected;
+		goto reterr;
+	}
+	if (req->status == REQ_STATUS_ERROR) {
+		P9_DPRINTK(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
+		err = req->t_err;
+	}
+	if ((err == -ERESTARTSYS) && (c->status == Connected)) {
+		P9_DPRINTK(P9_DEBUG_MUX, "flushing\n");
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+
+		if (c->trans_mod->cancel(c, req))
+			p9_client_flush(c, req);
+
+		/* if we received the response anyway, don't signal error */
+		if (req->status == REQ_STATUS_RCVD)
+			err = 0;
+	}
+	if (sigpending) {
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
 	}
+	if (err < 0)
+		goto reterr;
 
+	err = p9_check_zc_errors(c, req, uidata, in_hdrlen, kern_buf);
+	trace_9p_client_res(c, type, req->rc->tag, err);
+	if (!err)
+		return req;
 reterr:
-	P9_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d error: %d\n", c, type,
-									err);
 	p9_free_req(c, req);
 	return ERR_PTR(err);
 }
@@ -769,7 +942,7 @@ static int p9_client_version(struct p9_client *c)
 	err = p9pdu_readf(req->rc, c->proto_version, "ds", &msize, &version);
 	if (err) {
 		P9_DPRINTK(P9_DEBUG_9P, "version error %d\n", err);
-		P9_DUMP_PKT(1, req->rc);
+		trace_9p_protocol_dump(c, req->rc);
 		goto error;
 	}
 
@@ -906,15 +1079,14 @@ EXPORT_SYMBOL(p9_client_begin_disconnect);
 struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 	char *uname, u32 n_uname, char *aname)
 {
-	int err;
+	int err = 0;
 	struct p9_req_t *req;
 	struct p9_fid *fid;
 	struct p9_qid qid;
 
-	P9_DPRINTK(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
-					afid ? afid->fid : -1, uname, aname);
-	err = 0;
 
+	P9_DPRINTK(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
+		   afid ? afid->fid : -1, uname, aname);
 	fid = p9_fid_create(clnt);
 	if (IS_ERR(fid)) {
 		err = PTR_ERR(fid);
@@ -931,7 +1103,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 
 	err = p9pdu_readf(req->rc, clnt->proto_version, "Q", &qid);
 	if (err) {
-		P9_DUMP_PKT(1, req->rc);
+		trace_9p_protocol_dump(clnt, req->rc);
 		p9_free_req(clnt, req);
 		goto error;
 	}
@@ -991,7 +1163,7 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 
 	err = p9pdu_readf(req->rc, clnt->proto_version, "R", &nwqids, &wqids);
 	if (err) {
-		P9_DUMP_PKT(1, req->rc);
+		trace_9p_protocol_dump(clnt, req->rc);
 		p9_free_req(clnt, req);
 		goto clunk_fid;
 	}
@@ -1058,7 +1230,7 @@ int p9_client_open(struct p9_fid *fid, int mode)
 
 	err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", &qid, &iounit);
 	if (err) {
-		P9_DUMP_PKT(1, req->rc);
+		trace_9p_protocol_dump(