Merge tag '9p-for-5.20' of https://github.com/martinetd/linux

Pull 9p updates from Dominique Martinet:

 - a couple of fixes

 - add a tracepoint for fid refcounting

 - some cleanup/followup on fid lookup

 - some cleanup around req refcounting

* tag '9p-for-5.20' of https://github.com/martinetd/linux:
  net/9p: Initialize the iounit field during fid creation
  net: 9p: fix refcount leak in p9_read_work() error handling
  9p: roll p9_tag_remove into p9_req_put
  9p: Add client parameter to p9_req_put()
  9p: Drop kref usage
  9p: Fix some kernel-doc comments
  9p fid refcount: cleanup p9_fid_put calls
  9p fid refcount: add a 9p_fid_ref tracepoint
  9p fid refcount: add p9_fid_get/put wrappers
  9p: Fix minor typo in code comment
  9p: Remove unnecessary variable for old fids while walking from d_parent
  9p: Make the path walk logic more clear about when cloning is required
  9p: Track the root fid with its own variable during lookups

1 files changed, 86 insertions, 82 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
index d403085b9ef5..5bf4dfef0c70 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -298,14 +298,14 @@ p9_tag_alloc(struct p9_client *c, int8_t type, unsigned int max_size)
 	/* Init ref to two because in the general case there is one ref
 	 * that is put asynchronously by a writer thread, one ref
 	 * temporarily given by p9_tag_lookup and put by p9_client_cb
-	 * in the recv thread, and one ref put by p9_tag_remove in the
+	 * in the recv thread, and one ref put by p9_req_put in the
 	 * main thread. The only exception is virtio that does not use
 	 * p9_tag_lookup but does not have a writer thread either
 	 * (the write happens synchronously in the request/zc_request
 	 * callback), so p9_client_cb eats the second ref there
 	 * as the pointer is duplicated directly by virtqueue_add_sgs()
 	 */
-	refcount_set(&req->refcount.refcount, 2);
+	refcount_set(&req->refcount, 2);
 
 	return req;
 
@@ -341,7 +341,7 @@ again:
 		if (!p9_req_try_get(req))
 			goto again;
 		if (req->tc.tag != tag) {
-			p9_req_put(req);
+			p9_req_put(c, req);
 			goto again;
 		}
 	}
@@ -358,30 +358,28 @@ EXPORT_SYMBOL(p9_tag_lookup);
  *
  * Context: Any context.
  */
-static int p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
+static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
 {
 	unsigned long flags;
 	u16 tag = r->tc.tag;
 
-	p9_debug(P9_DEBUG_MUX, "clnt %p req %p tag: %d\n", c, r, tag);
+	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
 	spin_lock_irqsave(&c->lock, flags);
 	idr_remove(&c->reqs, tag);
 	spin_unlock_irqrestore(&c->lock, flags);
-	return p9_req_put(r);
 }
 
-static void p9_req_free(struct kref *ref)
+int p9_req_put(struct p9_client *c, struct p9_req_t *r)
 {
-	struct p9_req_t *r = container_of(ref, struct p9_req_t, refcount);
+	if (refcount_dec_and_test(&r->refcount)) {
+		p9_tag_remove(c, r);
 
-	p9_fcall_fini(&r->tc);
-	p9_fcall_fini(&r->rc);
-	kmem_cache_free(p9_req_cache, r);
-}
-
-int p9_req_put(struct p9_req_t *r)
-{
-	return kref_put(&r->refcount, p9_req_free);
+		p9_fcall_fini(&r->tc);
+		p9_fcall_fini(&r->rc);
+		kmem_cache_free(p9_req_cache, r);
+		return 1;
+	}
+	return 0;
 }
 EXPORT_SYMBOL(p9_req_put);
 
@@ -400,7 +398,7 @@ static void p9_tag_cleanup(struct p9_client *c)
 	rcu_read_lock();
 	idr_for_each_entry(&c->reqs, req, id) {
 		pr_info("Tag %d still in use\n", id);
-		if (p9_tag_remove(c, req) == 0)
+		if (p9_req_put(c, req) == 0)
 			pr_warn("Packet with tag %d has still references",
 				req->tc.tag);
 	}
@@ -426,7 +424,7 @@ void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
 
 	wake_up(&req->wq);
 	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
-	p9_req_put(req);
+	p9_req_put(c, req);
 }
 EXPORT_SYMBOL(p9_client_cb);
 
@@ -589,7 +587,7 @@ static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
 			c->trans_mod->cancelled(c, oldreq);
 	}
 
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	return 0;
 }
 
@@ -623,9 +621,9 @@ static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
 	trace_9p_client_req(c, type, req->tc.tag);
 	return req;
 reterr:
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	/* We have to put also the 2nd reference as it won't be used */
-	p9_req_put(req);
+	p9_req_put(c, req);
 	return ERR_PTR(err);
 }
 
@@ -635,7 +633,7 @@ reterr:
  * @type: type of request
  * @fmt: protocol format string (see protocol.c)
  *
- * Returns request structure (which client must free using p9_tag_remove)
+ * Returns request structure (which client must free using p9_req_put)
  */
 
 static struct p9_req_t *
@@ -662,7 +660,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
 	err = c->trans_mod->request(c, req);
 	if (err < 0) {
 		/* write won't happen */
-		p9_req_put(req);
+		p9_req_put(c, req);
 		if (err != -ERESTARTSYS && err != -EFAULT)
 			c->status = Disconnected;
 		goto recalc_sigpending;
@@ -713,7 +711,7 @@ recalc_sigpending:
 	if (!err)
 		return req;
 reterr:
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	return ERR_PTR(safe_errno(err));
 }
 
@@ -728,7 +726,7 @@ reterr:
  * @in_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_tag_remove)
+ * Returns request structure (which client must free using p9_req_put)
  */
 static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
 					 struct iov_iter *uidata,
@@ -795,7 +793,7 @@ recalc_sigpending:
 	if (!err)
 		return req;
 reterr:
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 	return ERR_PTR(safe_errno(err));
 }
 
@@ -805,16 +803,13 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 	struct p9_fid *fid;
 
 	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
-	fid = kmalloc(sizeof(*fid), GFP_KERNEL);
+	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
 	if (!fid)
 		return NULL;
 
-	memset(&fid->qid, 0, sizeof(fid->qid));
 	fid->mode = -1;
 	fid->uid = current_fsuid();
 	fid->clnt = clnt;
-	fid->rdir = NULL;
-	fid->fid = 0;
 	refcount_set(&fid->count, 1);
 
 	idr_preload(GFP_KERNEL);
@@ -823,8 +818,10 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
 			    GFP_NOWAIT);
 	spin_unlock_irq(&clnt->lock);
 	idr_preload_end();
-	if (!ret)
+	if (!ret) {
+		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
 		return fid;
+	}
 
 	kfree(fid);
 	return NULL;
@@ -836,6 +833,7 @@ static void p9_fid_destroy(struct p9_fid *fid)
 	unsigned long flags;
 
 	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
+	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
 	clnt = fid->clnt;
 	spin_lock_irqsave(&clnt->lock, flags);
 	idr_remove(&clnt->fids, fid->fid);
@@ -844,6 +842,21 @@ static void p9_fid_destroy(struct p9_fid *fid)
 	kfree(fid);
 }
 
+/* We also need to export tracepoint symbols for tracepoint_enabled() */
+EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
+
+void do_trace_9p_fid_get(struct p9_fid *fid)
+{
+	trace_9p_fid_ref(fid, P9_FID_REF_GET);
+}
+EXPORT_SYMBOL(do_trace_9p_fid_get);
+
+void do_trace_9p_fid_put(struct p9_fid *fid)
+{
+	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
+}
+EXPORT_SYMBOL(do_trace_9p_fid_put);
+
 static int p9_client_version(struct p9_client *c)
 {
 	int err = 0;
@@ -906,7 +919,7 @@ static int p9_client_version(struct p9_client *c)
 
 error:
 	kfree(version);
-	p9_tag_remove(c, req);
+	p9_req_put(c, req);
 
 	return err;
 }
@@ -1060,7 +1073,7 @@ 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) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1069,7 +1082,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 
 	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return fid;
 
 error:
@@ -1116,10 +1129,10 @@ 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) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto clunk_fid;
 	}
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 
 	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
 
@@ -1144,7 +1157,7 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 
 clunk_fid:
 	kfree(wqids);
-	p9_client_clunk(fid);
+	p9_fid_put(fid);
 	fid = NULL;
 
 error:
@@ -1195,7 +1208,7 @@ int p9_client_open(struct p9_fid *fid, int mode)
 	fid->iounit = iounit;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1239,7 +1252,7 @@ int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
 	ofid->iounit = iounit;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1283,7 +1296,7 @@ int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
 	fid->iounit = iounit;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1317,7 +1330,7 @@ int p9_client_symlink(struct p9_fid *dfid, const char *name,
 		 qid->type, qid->path, qid->version);
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1337,7 +1350,7 @@ int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newna
 		return PTR_ERR(req);
 
 	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return 0;
 }
 EXPORT_SYMBOL(p9_client_link);
@@ -1361,7 +1374,7 @@ int p9_client_fsync(struct p9_fid *fid, int datasync)
 
 	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 
 error:
 	return err;
@@ -1375,15 +1388,6 @@ int p9_client_clunk(struct p9_fid *fid)
 	struct p9_req_t *req;
 	int retries = 0;
 
-	if (!fid || IS_ERR(fid)) {
-		pr_warn("%s (%d): Trying to clunk with invalid fid\n",
-			__func__, task_pid_nr(current));
-		dump_stack();
-		return 0;
-	}
-	if (!refcount_dec_and_test(&fid->count))
-		return 0;
-
 again:
 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
 		 fid->fid, retries);
@@ -1398,7 +1402,7 @@ again:
 
 	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	/* Fid is not valid even after a failed clunk
 	 * If interrupted, retry once then give up and
@@ -1432,10 +1436,10 @@ int p9_client_remove(struct p9_fid *fid)
 
 	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	if (err == -ERESTARTSYS)
-		p9_client_clunk(fid);
+		p9_fid_put(fid);
 	else
 		p9_fid_destroy(fid);
 	return err;
@@ -1459,7 +1463,7 @@ int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1527,7 +1531,7 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 			   "D", &count, &dataptr);
 	if (*err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		return 0;
 	}
 	if (rsize < count) {
@@ -1542,13 +1546,13 @@ p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
 
 		if (n != count) {
 			*err = -EFAULT;
-			p9_tag_remove(clnt, req);
+			p9_req_put(clnt, req);
 			return n;
 		}
 	} else {
 		iov_iter_advance(to, count);
 	}
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return count;
 }
 EXPORT_SYMBOL(p9_client_read_once);
@@ -1591,7 +1595,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &count);
 		if (*err) {
 			trace_9p_protocol_dump(clnt, &req->rc);
-			p9_tag_remove(clnt, req);
+			p9_req_put(clnt, req);
 			break;
 		}
 		if (rsize < count) {
@@ -1601,7 +1605,7 @@ p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
 
 		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
 
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		iov_iter_advance(from, count);
 		total += count;
 		offset += count;
@@ -1636,7 +1640,7 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1653,7 +1657,7 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 		 from_kgid(&init_user_ns, ret->n_gid),
 		 from_kuid(&init_user_ns, ret->n_muid));
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return ret;
 
 error:
@@ -1689,7 +1693,7 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1715,7 +1719,7 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 		 ret->st_btime_sec, ret->st_btime_nsec,
 		 ret->st_gen, ret->st_data_version);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return ret;
 
 error:
@@ -1787,7 +1791,7 @@ int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
 
 	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1819,7 +1823,7 @@ int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
 		goto error;
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1847,7 +1851,7 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
 			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto error;
 	}
 
@@ -1856,7 +1860,7 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
 		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
 		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1884,7 +1888,7 @@ int p9_client_rename(struct p9_fid *fid,
 
 	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1914,7 +1918,7 @@ int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
 	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
 		 newdirfid->fid, new_name);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -1950,15 +1954,15 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
 	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
 	if (err) {
 		trace_9p_protocol_dump(clnt, &req->rc);
-		p9_tag_remove(clnt, req);
+		p9_req_put(clnt, req);
 		goto clunk_fid;
 	}
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
 		 attr_fid->fid, *attr_size);
 	return attr_fid;
 clunk_fid:
-	p9_client_clunk(attr_fid);
+	p9_fid_put(attr_fid);
 	attr_fid = NULL;
 error:
 	if (attr_fid && attr_fid != file_fid)
@@ -1987,7 +1991,7 @@ int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
 		goto error;
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -2049,11 +2053,11 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 	if (non_zc)
 		memmove(data, dataptr, count);
 
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return count;
 
 free_and_error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 error:
 	return err;
 }
@@ -2085,7 +2089,7 @@ int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
 		 qid->type, qid->path, qid->version);
 
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_mknod_dotl);
@@ -2115,7 +2119,7 @@ int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
 		 qid->path, qid->version);
 
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_mkdir_dotl);
@@ -2147,7 +2151,7 @@ int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_lock_dotl);
@@ -2184,7 +2188,7 @@ int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
 		 glock->type, glock->start, glock->length,
 		 glock->proc_id, glock->client_id);
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_getlock_dotl);
@@ -2210,7 +2214,7 @@ int p9_client_readlink(struct p9_fid *fid, char **target)
 	}
 	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
 error:
-	p9_tag_remove(clnt, req);
+	p9_req_put(clnt, req);
 	return err;
 }
 EXPORT_SYMBOL(p9_client_readlink);