Merge tag 'nfs-for-5.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs

Pull NFS client updates from Trond Myklebust:
 "Highlights include:

  Features:

   - NFSv3: Add emulation of lookupp() to improve open_by_filehandle()
     support

   - A series of patches to improve readdir performance, particularly
     with large directories

   - Basic support for using NFS/RDMA with the pNFS files and flexfiles
     drivers

   - Micro-optimisations for RDMA

   - RDMA tracing improvements

  Bugfixes:

   - Fix a long standing bug with xs_read_xdr_buf() when receiving
     partial pages (Dan Aloni)

   - Various fixes for getxattr and listxattr, when used over non-TCP
     transports

   - Fixes for containerised NFS from Sargun Dhillon

   - switch nfsiod to be an UNBOUND workqueue (Neil Brown)

   - READDIR should not ask for security label information if there is
     no LSM policy (Olga Kornievskaia)

   - Avoid using interval-based rebinding with TCP in lockd (Calum
     Mackay)

   - A series of RPC and NFS layer fixes to support the NFSv4.2
     READ_PLUS code

   - A couple of fixes for pnfs/flexfiles read failover

  Cleanups:

   - Various cleanups for the SUNRPC xdr code in conjunction with the
     READ_PLUS fixes"

* tag 'nfs-for-5.11-1' of git://git.linux-nfs.org/projects/trondmy/linux-nfs: (90 commits)
  NFS/pNFS: Fix a typo in ff_layout_resend_pnfs_read()
  pNFS/flexfiles: Avoid spurious layout returns in ff_layout_choose_ds_for_read
  NFSv4/pnfs: Add tracing for the deviceid cache
  fs/lockd: convert comma to semicolon
  NFSv4.2: fix error return on memory allocation failure
  NFSv4.2/pnfs: Don't use READ_PLUS with pNFS yet
  NFSv4.2: Deal with potential READ_PLUS data extent buffer overflow
  NFSv4.2: Don't error when exiting early on a READ_PLUS buffer overflow
  NFSv4.2: Handle hole lengths that exceed the READ_PLUS read buffer
  NFSv4.2: decode_read_plus_hole() needs to check the extent offset
  NFSv4.2: decode_read_plus_data() must skip padding after data segment
  NFSv4.2: Ensure we always reset the result->count in decode_read_plus()
  SUNRPC: When expanding the buffer, we may need grow the sparse pages
  SUNRPC: Cleanup - constify a number of xdr_buf helpers
  SUNRPC: Clean up open coded setting of the xdr_stream 'nwords' field
  SUNRPC: _copy_to/from_pages() now check for zero length
  SUNRPC: Cleanup xdr_shrink_bufhead()
  SUNRPC: Fix xdr_expand_hole()
  SUNRPC: Fixes for xdr_align_data()
  SUNRPC: _shift_data_left/right_pages should check the shift length
  ...

1 files changed, 87 insertions, 30 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index f6c17e75f20e..691ccf8049a4 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -151,33 +151,94 @@ out:
 }
 EXPORT_SYMBOL_GPL(xprt_unregister_transport);
 
-/**
- * xprt_load_transport - load a transport implementation
- * @transport_name: transport to load
- *
- * Returns:
- * 0:		transport successfully loaded
- * -ENOENT:	transport module not available
- */
-int xprt_load_transport(const char *transport_name)
+static void
+xprt_class_release(const struct xprt_class *t)
 {
-	struct xprt_class *t;
-	int result;
+	module_put(t->owner);
+}
+
+static const struct xprt_class *
+xprt_class_find_by_ident_locked(int ident)
+{
+	const struct xprt_class *t;
+
+	list_for_each_entry(t, &xprt_list, list) {
+		if (t->ident != ident)
+			continue;
+		if (!try_module_get(t->owner))
+			continue;
+		return t;
+	}
+	return NULL;
+}
+
+static const struct xprt_class *
+xprt_class_find_by_ident(int ident)
+{
+	const struct xprt_class *t;
 
-	result = 0;
 	spin_lock(&xprt_list_lock);
+	t = xprt_class_find_by_ident_locked(ident);
+	spin_unlock(&xprt_list_lock);
+	return t;
+}
+
+static const struct xprt_class *
+xprt_class_find_by_netid_locked(const char *netid)
+{
+	const struct xprt_class *t;
+	unsigned int i;
+
 	list_for_each_entry(t, &xprt_list, list) {
-		if (strcmp(t->name, transport_name) == 0) {
-			spin_unlock(&xprt_list_lock);
-			goto out;
+		for (i = 0; t->netid[i][0] != '\0'; i++) {
+			if (strcmp(t->netid[i], netid) != 0)
+				continue;
+			if (!try_module_get(t->owner))
+				continue;
+			return t;
 		}
 	}
+	return NULL;
+}
+
+static const struct xprt_class *
+xprt_class_find_by_netid(const char *netid)
+{
+	const struct xprt_class *t;
+
+	spin_lock(&xprt_list_lock);
+	t = xprt_class_find_by_netid_locked(netid);
+	if (!t) {
+		spin_unlock(&xprt_list_lock);
+		request_module("rpc%s", netid);
+		spin_lock(&xprt_list_lock);
+		t = xprt_class_find_by_netid_locked(netid);
+	}
 	spin_unlock(&xprt_list_lock);
-	result = request_module("xprt%s", transport_name);
-out:
-	return result;
+	return t;
+}
+
+/**
+ * xprt_find_transport_ident - convert a netid into a transport identifier
+ * @netid: transport to load
+ *
+ * Returns:
+ * > 0:		transport identifier
+ * -ENOENT:	transport module not available
+ */
+int xprt_find_transport_ident(const char *netid)
+{
+	const struct xprt_class *t;
+	int ret;
+
+	t = xprt_class_find_by_netid(netid);
+	if (!t)
+		return -ENOENT;
+	ret = t->ident;
+	xprt_class_release(t);
+	return ret;
 }
-EXPORT_SYMBOL_GPL(xprt_load_transport);
+EXPORT_SYMBOL_GPL(xprt_find_transport_ident);
 
 static void xprt_clear_locked(struct rpc_xprt *xprt)
 {
@@ -1896,21 +1957,17 @@ static void xprt_init(struct rpc_xprt *xprt, struct net *net)
 struct rpc_xprt *xprt_create_transport(struct xprt_create *args)
 {
 	struct rpc_xprt	*xprt;
-	struct xprt_class *t;
+	const struct xprt_class *t;
 
-	spin_lock(&xprt_list_lock);
-	list_for_each_entry(t, &xprt_list, list) {
-		if (t->ident == args->ident) {
-			spin_unlock(&xprt_list_lock);
-			goto found;
-		}
+	t = xprt_class_find_by_ident(args->ident);
+	if (!t) {
+		dprintk("RPC: transport (%d) not supported\n", args->ident);
+		return ERR_PTR(-EIO);
 	}
-	spin_unlock(&xprt_list_lock);
-	dprintk("RPC: transport (%d) not supported\n", args->ident);
-	return ERR_PTR(-EIO);
 
-found:
 	xprt = t->setup(args);
+	xprt_class_release(t);
+
 	if (IS_ERR(xprt))
 		goto out;
 	if (args->flags & XPRT_CREATE_NO_IDLE_TIMEOUT)