[PATCH] v9fs: new multiplexer implementation

New multiplexer implementation. Decreases the number of kernel threads
required. Better handling when the user process receives a signal.

Signed-off-by: Latchesar Ionkov <lucho@ionkov.net>
Cc: Eric Van Hensbergen <ericvh@ericvh.myip.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 45 insertions, 41 deletions

diff --git a/fs/9p/conv.c b/fs/9p/conv.c
index 18121af99d3e..1b9b15dfeaf0 100644
--- a/fs/9p/conv.c
+++ b/fs/9p/conv.c
@@ -208,7 +208,7 @@ static inline char *buf_get_stringb(struct cbuf *buf, struct cbuf *sbuf)
         len = buf_get_int16(buf);
 
         if (!buf_check_overflow(buf) && buf_check_size(buf, len) &&
-                buf_check_size(sbuf, len+1)) {
+                buf_check_size(sbuf, len + 1)) {
 
                 memcpy(sbuf->p, buf->p, len);
                 sbuf->p[len] = 0;
@@ -252,13 +252,12 @@ static inline void *buf_get_datab(struct cbuf *buf, struct cbuf *dbuf,
 
 /**
  * v9fs_size_stat - calculate the size of a variable length stat struct
- * @v9ses: session information
  * @stat: metadata (stat) structure
+ * @extended: non-zero if 9P2000.u
  *
  */
 
-static int v9fs_size_stat(struct v9fs_session_info *v9ses,
-                          struct v9fs_stat *stat)
+static int v9fs_size_stat(struct v9fs_stat *stat, int extended)
 {
         int size = 0;
 
@@ -288,7 +287,7 @@ static int v9fs_size_stat(struct v9fs_session_info *v9ses,
         if (stat->muid)
                 size += strlen(stat->muid);
 
-        if (v9ses->extended) {
+        if (extended) {
                 size += 4 +     /* n_uid[4] */
                     4 +         /* n_gid[4] */
                     4 +         /* n_muid[4] */
@@ -302,15 +301,14 @@ static int v9fs_size_stat(struct v9fs_session_info *v9ses,
 
 /**
  * serialize_stat - safely format a stat structure for transmission
- * @v9ses: session info
  * @stat: metadata (stat) structure
  * @bufp: buffer to serialize structure into
+ * @extended: non-zero if 9P2000.u
  *
  */
 
 static int
-serialize_stat(struct v9fs_session_info *v9ses, struct v9fs_stat *stat,
-               struct cbuf *bufp)
+serialize_stat(struct v9fs_stat *stat, struct cbuf *bufp, int extended)
 {
         buf_put_int16(bufp, stat->size);
         buf_put_int16(bufp, stat->type);
@@ -328,7 +326,7 @@ serialize_stat(struct v9fs_session_info *v9ses, struct v9fs_stat *stat,
         buf_put_string(bufp, stat->gid);
         buf_put_string(bufp, stat->muid);
 
-        if (v9ses->extended) {
+        if (extended) {
                 buf_put_string(bufp, stat->extension);
                 buf_put_int32(bufp, stat->n_uid);
                 buf_put_int32(bufp, stat->n_gid);
@@ -343,16 +341,16 @@ serialize_stat(struct v9fs_session_info *v9ses, struct v9fs_stat *stat,
 
 /**
  * deserialize_stat - safely decode a recieved metadata (stat) structure
- * @v9ses: session info
  * @bufp: buffer to deserialize
  * @stat: metadata (stat) structure
  * @dbufp: buffer to deserialize variable strings into
+ * @extended: non-zero if 9P2000.u
  *
  */
 
 static inline int
-deserialize_stat(struct v9fs_session_info *v9ses, struct cbuf *bufp,
-                 struct v9fs_stat *stat, struct cbuf *dbufp)
+deserialize_stat(struct cbuf *bufp, struct v9fs_stat *stat,
+                 struct cbuf *dbufp, int extended)
 {
 
         stat->size = buf_get_int16(bufp);
@@ -370,7 +368,7 @@ deserialize_stat(struct v9fs_session_info *v9ses, struct cbuf *bufp,
         stat->gid = buf_get_stringb(bufp, dbufp);
         stat->muid = buf_get_stringb(bufp, dbufp);
 
-        if (v9ses->extended) {
+        if (extended) {
                 stat->extension = buf_get_stringb(bufp, dbufp);
                 stat->n_uid = buf_get_int32(bufp);
                 stat->n_gid = buf_get_int32(bufp);
@@ -385,20 +383,20 @@ deserialize_stat(struct v9fs_session_info *v9ses, struct cbuf *bufp,
 
 /**
  * deserialize_statb - wrapper for decoding a received metadata structure
- * @v9ses: session info
  * @bufp: buffer to deserialize
  * @dbufp: buffer to deserialize variable strings into
+ * @extended: non-zero if 9P2000.u
  *
  */
 
-static inline struct v9fs_stat *deserialize_statb(struct v9fs_session_info
-                                                  *v9ses, struct cbuf *bufp,
-                                                  struct cbuf *dbufp)
+static inline struct v9fs_stat *deserialize_statb(struct cbuf *bufp,
+                                                  struct cbuf *dbufp,
+                                                  int extended)
 {
         struct v9fs_stat *ret = buf_alloc(dbufp, sizeof(struct v9fs_stat));
 
         if (ret) {
-                int n = deserialize_stat(v9ses, bufp, ret, dbufp);
+                int n = deserialize_stat(bufp, ret, dbufp, extended);
                 if (n <= 0)
                         return NULL;
         }
@@ -408,17 +406,16 @@ static inline struct v9fs_stat *deserialize_statb(struct v9fs_session_info
 
 /**
  * v9fs_deserialize_stat - decode a received metadata structure
- * @v9ses: session info
  * @buf: buffer to deserialize
  * @buflen: length of received buffer
  * @stat: metadata structure to decode into
  * @statlen: length of destination metadata structure
+ * @extended: non-zero if 9P2000.u
  *
  */
 
-int
-v9fs_deserialize_stat(struct v9fs_session_info *v9ses, void *buf,
-                      u32 buflen, struct v9fs_stat *stat, u32 statlen)
+int v9fs_deserialize_stat(void *buf, u32 buflen, struct v9fs_stat *stat,
+                          u32 statlen, int extended)
 {
         struct cbuf buffer;
         struct cbuf *bufp = &buffer;
@@ -429,11 +426,10 @@ v9fs_deserialize_stat(struct v9fs_session_info *v9ses, void *buf,
         buf_init(dbufp, (char *)stat + sizeof(struct v9fs_stat),
                  statlen - sizeof(struct v9fs_stat));
 
-        return deserialize_stat(v9ses, bufp, stat, dbufp);
+        return deserialize_stat(bufp, stat, dbufp, extended);
 }
 
-static inline int
-v9fs_size_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall)
+static inline int v9fs_size_fcall(struct v9fs_fcall *fcall, int extended)
 {
         int size = 4 + 1 + 2;   /* size[4] msg[1] tag[2] */
         int i = 0;
@@ -485,7 +481,7 @@ v9fs_size_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall)
                 break;
         case TWSTAT:            /* fid[4] stat[n] */
                 fcall->params.twstat.stat->size =
-                    v9fs_size_stat(v9ses, fcall->params.twstat.stat);
+                    v9fs_size_stat(fcall->params.twstat.stat, extended);
                 size += 4 + 2 + 2 + fcall->params.twstat.stat->size;
         }
         return size;
@@ -493,16 +489,16 @@ v9fs_size_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall)
 
 /*
  * v9fs_serialize_fcall - marshall fcall struct into a packet
- * @v9ses: session information
  * @fcall: structure to convert
  * @data: buffer to serialize fcall into
  * @datalen: length of buffer to serialize fcall into
+ * @extended: non-zero if 9P2000.u
  *
  */
 
 int
-v9fs_serialize_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall,
-                     void *data, u32 datalen)
+v9fs_serialize_fcall(struct v9fs_fcall *fcall, void *data, u32 datalen,
+                     int extended)
 {
         int i = 0;
         struct v9fs_stat *stat = NULL;
@@ -516,7 +512,7 @@ v9fs_serialize_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall,
                 return -EINVAL;
         }
 
-        fcall->size = v9fs_size_fcall(v9ses, fcall);
+        fcall->size = v9fs_size_fcall(fcall, extended);
 
         buf_put_int32(bufp, fcall->size);
         buf_put_int8(bufp, fcall->id);
@@ -591,31 +587,31 @@ v9fs_serialize_fcall(struct v9fs_session_info *v9ses, struct v9fs_fcall *fcall,
                 stat = fcall->params.twstat.stat;
 
                 buf_put_int16(bufp, stat->size + 2);
-                serialize_stat(v9ses, stat, bufp);
+                serialize_stat(stat, bufp, extended);
                 break;
         }
 
-        if (buf_check_overflow(bufp))
+        if (buf_check_overflow(bufp)) {
+                dprintk(DEBUG_ERROR, "buffer overflow\n");
                 return -EIO;
+        }
 
         return fcall->size;
 }
 
 /**
  * deserialize_fcall - unmarshal a response
- * @v9ses: session information
- * @msgsize: size of rcall message
  * @buf: recieved buffer
  * @buflen: length of received buffer
  * @rcall: fcall structure to populate
  * @rcalllen: length of fcall structure to populate
+ * @extended: non-zero if 9P2000.u
  *
  */
 
 int
-v9fs_deserialize_fcall(struct v9fs_session_info *v9ses, u32 msgsize,
-                       void *buf, u32 buflen, struct v9fs_fcall *rcall,
-                       int rcalllen)
+v9fs_deserialize_fcall(void *buf, u32 buflen, struct v9fs_fcall *rcall,
+                       int rcalllen, int extended)
 {
 
         struct cbuf buffer;
@@ -628,7 +624,7 @@ v9fs_deserialize_fcall(struct v9fs_session_info *v9ses, u32 msgsize,
         buf_init(dbufp, (char *)rcall + sizeof(struct v9fs_fcall),
                  rcalllen - sizeof(struct v9fs_fcall));
 
-        rcall->size = msgsize;
+        rcall->size = buf_get_int32(bufp);
         rcall->id = buf_get_int8(bufp);
         rcall->tag = buf_get_int16(bufp);
 
@@ -651,6 +647,12 @@ v9fs_deserialize_fcall(struct v9fs_session_info *v9ses, u32 msgsize,
                 break;
         case RWALK:
                 rcall->params.rwalk.nwqid = buf_get_int16(bufp);
+                if (rcall->params.rwalk.nwqid > 16) {
+                        eprintk(KERN_ERR, "Rwalk with more than 16 qids: %d\n",
+                                rcall->params.rwalk.nwqid);
+                        return -EPROTO;
+                }
+
                 rcall->params.rwalk.wqids = buf_alloc(dbufp,
                       rcall->params.rwalk.nwqid * sizeof(struct v9fs_qid));
                 if (rcall->params.rwalk.wqids)
@@ -690,19 +692,21 @@ v9fs_deserialize_fcall(struct v9fs_session_info *v9ses, u32 msgsize,
         case RSTAT:
                 buf_get_int16(bufp);
                 rcall->params.rstat.stat =
-                    deserialize_statb(v9ses, bufp, dbufp);
+                    deserialize_statb(bufp, dbufp, extended);
                 break;
         case RWSTAT:
                 break;
         case RERROR:
                 rcall->params.rerror.error = buf_get_stringb(bufp, dbufp);
-                if (v9ses->extended)
+                if (extended)
                         rcall->params.rerror.errno = buf_get_int16(bufp);
                 break;
         }
 
-        if (buf_check_overflow(bufp) || buf_check_overflow(dbufp))
+        if (buf_check_overflow(bufp) || buf_check_overflow(dbufp)) {
+                dprintk(DEBUG_ERROR, "buffer overflow\n");
                 return -EIO;
+        }
 
         return rcall->size;
 }