net/9p: Convert net/9p protocol dumps to tracepoints

This helps in more control over debugging.
root@qemu-img-64:~# ls /pass/123
ls: cannot access /pass/123: No such file or directory
root@qemu-img-64:~# cat /sys/kernel/debug/tracing/trace
# tracer: nop
#
#           TASK-PID    CPU#    TIMESTAMP  FUNCTION
#              | |       |          |         |
              ls-1536  [001]    70.928584: 9p_protocol_dump: clnt 18446612132784021504 P9_TWALK(tag = 1)
000: 16 00 00 00 6e 01 00 01 00 00 00 02 00 00 00 01
010: 00 03 00 31 32 33 00 00 00 ff ff ff ff 00 00 00

              ls-1536  [001]    70.928587: <stack trace>
 => trace_9p_protocol_dump
 => p9pdu_finalize
 => p9_client_rpc
 => p9_client_walk
 => v9fs_vfs_lookup
 => d_alloc_and_lookup
 => walk_component
 => path_lookupat
              ls-1536  [000]    70.929696: 9p_protocol_dump: clnt 18446612132784021504 P9_RLERROR(tag = 1)
000: 0b 00 00 00 07 01 00 02 00 00 00 4e 03 00 02 00
010: 00 00 00 00 03 00 02 00 00 00 00 00 ff 43 00 00

              ls-1536  [000]    70.929697: <stack trace>
 => trace_9p_protocol_dump
 => p9_client_rpc
 => p9_client_walk
 => v9fs_vfs_lookup
 => d_alloc_and_lookup
 => walk_component
 => path_lookupat
 => do_path_lookup

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

3 files changed, 54 insertions, 79 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index b1c02187f862..854ca7a911c4 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
@@ -464,11 +467,15 @@ 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;
 
@@ -525,6 +532,11 @@ static int p9_check_zc_errors(struct p9_client *c, struct p9_req_t *req,
         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;
@@ -684,7 +696,8 @@ static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
         err = p9pdu_vwritef(req->tc, c->proto_version, fmt, 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);
@@ -755,13 +768,10 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
                 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_DPRINTK(P9_DEBUG_MUX,
-                   "exit: client %p op %d error: %d\n", c, type, err);
         p9_free_req(c, req);
         return ERR_PTR(err);
 }
@@ -841,13 +851,10 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
                 goto reterr;
 
         err = p9_check_zc_errors(c, req, uidata, in_hdrlen, kern_buf);
-        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_DPRINTK(P9_DEBUG_MUX, "exit: client %p op %d error: %d\n", c, type,
-                                                                        err);
         p9_free_req(c, req);
         return ERR_PTR(err);
 }
@@ -935,7 +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;
         }
 
@@ -1072,15 +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);
@@ -1097,7 +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;
         }
@@ -1157,7 +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;
         }
@@ -1224,7 +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(clnt, req->rc);
                 goto free_and_error;
         }
 
@@ -1267,7 +1273,7 @@ int p9_client_create_dotl(struct p9_fid *ofid, char *name, u32 flags, u32 mode,
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "Qd", qid, &iounit);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto free_and_error;
         }
 
@@ -1312,7 +1318,7 @@ int p9_client_fcreate(struct p9_fid *fid, char *name, u32 perm, 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(clnt, req->rc);
                 goto free_and_error;
         }
 
@@ -1351,7 +1357,7 @@ int p9_client_symlink(struct p9_fid *dfid, char *name, char *symtgt, gid_t gid,
 
         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);
                 goto free_and_error;
         }
 
@@ -1542,12 +1548,11 @@ p9_client_read(struct p9_fid *fid, char *data, char __user *udata, u64 offset,
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto free_and_error;
         }
 
         P9_DPRINTK(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
-        P9_DUMP_PKT(1, req->rc);
 
         if (non_zc) {
                 if (data) {
@@ -1617,7 +1622,7 @@ p9_client_write(struct p9_fid *fid, char *data, const char __user *udata,
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "d", &count);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto free_and_error;
         }
 
@@ -1657,7 +1662,7 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "wS", &ignored, ret);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 p9_free_req(clnt, req);
                 goto error;
         }
@@ -1708,7 +1713,7 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "A", ret);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 p9_free_req(clnt, req);
                 goto error;
         }
@@ -1856,7 +1861,7 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
                 &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
                 &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 p9_free_req(clnt, req);
                 goto error;
         }
@@ -1963,7 +1968,7 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
         }
         err = p9pdu_readf(req->rc, clnt->proto_version, "q", attr_size);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 p9_free_req(clnt, req);
                 goto clunk_fid;
         }
@@ -2047,7 +2052,7 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "D", &count, &dataptr);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto free_and_error;
         }
 
@@ -2084,7 +2089,7 @@ int p9_client_mknod_dotl(struct p9_fid *fid, char *name, int mode,
 
         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);
                 goto error;
         }
         P9_DPRINTK(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n", qid->type,
@@ -2115,7 +2120,7 @@ int p9_client_mkdir_dotl(struct p9_fid *fid, char *name, int mode,
 
         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);
                 goto error;
         }
         P9_DPRINTK(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
@@ -2150,7 +2155,7 @@ int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "b", status);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto error;
         }
         P9_DPRINTK(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
@@ -2183,7 +2188,7 @@ int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
                         &glock->start, &glock->length, &glock->proc_id,
                         &glock->client_id);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto error;
         }
         P9_DPRINTK(P9_DEBUG_9P, "<<< RGETLOCK type %i start %lld length %lld "
@@ -2211,7 +2216,7 @@ int p9_client_readlink(struct p9_fid *fid, char **target)
 
         err = p9pdu_readf(req->rc, clnt->proto_version, "s", target);
         if (err) {
-                P9_DUMP_PKT(1, req->rc);
+                trace_9p_protocol_dump(clnt, req->rc);
                 goto error;
         }
         P9_DPRINTK(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
diff --git a/net/9p/protocol.c b/net/9p/protocol.c
index b7d4e8aa5383..55e10a96c902 100644
--- a/net/9p/protocol.c
+++ b/net/9p/protocol.c
@@ -37,40 +37,11 @@
 #include <net/9p/client.h>
 #include "protocol.h"
 
+#include <trace/events/9p.h>
+
 static int
 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
 
-#ifdef CONFIG_NET_9P_DEBUG
-void
-p9pdu_dump(int way, struct p9_fcall *pdu)
-{
-        int len = pdu->size;
-
-        if ((p9_debug_level & P9_DEBUG_VPKT) != P9_DEBUG_VPKT) {
-                if ((p9_debug_level & P9_DEBUG_PKT) == P9_DEBUG_PKT) {
-                        if (len > 32)
-                                len = 32;
-                } else {
-                        /* shouldn't happen */
-                        return;
-                }
-        }
-
-        if (way)
-                print_hex_dump_bytes("[9P] ", DUMP_PREFIX_OFFSET, pdu->sdata,
-                                                                        len);
-        else
-                print_hex_dump_bytes("]9P[ ", DUMP_PREFIX_OFFSET, pdu->sdata,
-                                                                        len);
-}
-#else
-void
-p9pdu_dump(int way, struct p9_fcall *pdu)
-{
-}
-#endif
-EXPORT_SYMBOL(p9pdu_dump);
-
 void p9stat_free(struct p9_wstat *stbuf)
 {
         kfree(stbuf->name);
@@ -551,7 +522,7 @@ p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
         return ret;
 }
 
-int p9stat_read(char *buf, int len, struct p9_wstat *st, int proto_version)
+int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
 {
         struct p9_fcall fake_pdu;
         int ret;
@@ -561,10 +532,10 @@ int p9stat_read(char *buf, int len, struct p9_wstat *st, int proto_version)
         fake_pdu.sdata = buf;
         fake_pdu.offset = 0;
 
-        ret = p9pdu_readf(&fake_pdu, proto_version, "S", st);
+        ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
         if (ret) {
                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
-                P9_DUMP_PKT(0, &fake_pdu);
+                trace_9p_protocol_dump(clnt, &fake_pdu);
         }
 
         return ret;
@@ -577,7 +548,7 @@ int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 }
 
-int p9pdu_finalize(struct p9_fcall *pdu)
+int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
 {
         int size = pdu->size;
         int err;
@@ -586,7 +557,7 @@ int p9pdu_finalize(struct p9_fcall *pdu)
         err = p9pdu_writef(pdu, 0, "d", size);
         pdu->size = size;
 
-        P9_DUMP_PKT(0, pdu);
+        trace_9p_protocol_dump(clnt, pdu);
         P9_DPRINTK(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n", pdu->size,
                                                         pdu->id, pdu->tag);
 
@@ -599,8 +570,8 @@ void p9pdu_reset(struct p9_fcall *pdu)
         pdu->size = 0;
 }
 
-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_fcall fake_pdu;
         int ret;
@@ -611,11 +582,11 @@ int p9dirent_read(char *buf, int len, struct p9_dirent *dirent,
         fake_pdu.sdata = buf;
         fake_pdu.offset = 0;
 
-        ret = p9pdu_readf(&fake_pdu, proto_version, "Qqbs", &dirent->qid,
-                        &dirent->d_off, &dirent->d_type, &nameptr);
+        ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
+                          &dirent->d_off, &dirent->d_type, &nameptr);
         if (ret) {
                 P9_DPRINTK(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
-                P9_DUMP_PKT(1, &fake_pdu);
+                trace_9p_protocol_dump(clnt, &fake_pdu);
                 goto out;
         }
 
diff --git a/net/9p/protocol.h b/net/9p/protocol.h
index a0eb8ff11f22..2cc525fa49fa 100644
--- a/net/9p/protocol.h
+++ b/net/9p/protocol.h
@@ -29,7 +29,6 @@ int p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
                                                                 va_list ap);
 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type);
-int p9pdu_finalize(struct p9_fcall *pdu);
-void p9pdu_dump(int, struct p9_fcall *);
+int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu);
 void p9pdu_reset(struct p9_fcall *pdu);
 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size);