[PATCH 4.9 087/175] SUNRPC: xprt_load_transport() needs to support the netid "rdma6"

Greg Kroah-Hartman
2020-12-28T13:04:22Z

From: Trond Myklebust <trond.myklebust@hammerspace.com>

[ Upstream commit d5aa6b22e2258f05317313ecc02efbb988ed6d38 ]

According to RFC5666, the correct netid for an IPv6 addressed RDMA
transport is "rdma6", which we've supported as a mount option since
Linux-4.7. The problem is when we try to load the module "xprtrdma6",
that will fail, since there is no modulealias of that name.

Fixes: 181342c5ebe8 ("xprtrdma: Add rdma6 option to support NFS/RDMA IPv6")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
include/linux/sunrpc/xprt.h | 1 +
net/sunrpc/xprt.c | 65 +++++++++++++++++++++++++--------
net/sunrpc/xprtrdma/module.c | 1 +
net/sunrpc/xprtrdma/transport.c | 1 +
net/sunrpc/xprtsock.c | 4 ++
5 files changed, 56 insertions(+), 16 deletions(-)

diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index a5da60b24d83e..15bab51a3aef1 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -310,6 +310,7 @@ struct xprt_class {
struct rpc_xprt * (*setup)(struct xprt_create *);
struct module *owner;
char name[32];
+ const char * netid[];
};

/*
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 1a8df242d26a1..9491fc81d50ad 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -143,31 +143,64 @@ out:
}
EXPORT_SYMBOL_GPL(xprt_unregister_transport);

+static void
+xprt_class_release(const struct xprt_class *t)
+{
+ module_put(t->owner);
+}
+
+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) {
+ 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);
+ return t;
+}
+
/**
* xprt_load_transport - load a transport implementation
- * @transport_name: transport to load
+ * @netid: transport to load
*
* Returns:
* 0: transport successfully loaded
* -ENOENT: transport module not available
*/
-int xprt_load_transport(const char *transport_name)
+int xprt_load_transport(const char *netid)
{
- struct xprt_class *t;
- int result;
+ const struct xprt_class *t;

- result = 0;
- spin_lock(&xprt_list_lock);
- list_for_each_entry(t, &xprt_list, list) {
- if (strcmp(t->name, transport_name) == 0) {
- spin_unlock(&xprt_list_lock);
- goto out;
- }
- }
- spin_unlock(&xprt_list_lock);
- result = request_module("xprt%s", transport_name);
-out:
- return result;
+ t = xprt_class_find_by_netid(netid);
+ if (!t)
+ return -ENOENT;
+ xprt_class_release(t);
+ return 0;
}
EXPORT_SYMBOL_GPL(xprt_load_transport);

diff --git a/net/sunrpc/xprtrdma/module.c b/net/sunrpc/xprtrdma/module.c
index 560712bd9fa2c..dd227de31a589 100644
--- a/net/sunrpc/xprtrdma/module.c
+++ b/net/sunrpc/xprtrdma/module.c
@@ -19,6 +19,7 @@ MODULE_DESCRIPTION("RPC/RDMA Transport");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_ALIAS("svcrdma");
MODULE_ALIAS("xprtrdma");
+MODULE_ALIAS("rpcrdma6");

static void __exit rpc_rdma_cleanup(void)
{
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index fa324fe739466..3ea3bb64b6d5c 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -777,6 +777,7 @@ static struct xprt_class xprt_rdma = {
.owner = THIS_MODULE,
.ident = XPRT_TRANSPORT_RDMA,
.setup = xprt_setup_rdma,
+ .netid = { "rdma", "rdma6", "" },
};

void xprt_rdma_cleanup(void)
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index f3f05148922a1..bf20ea2606389 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -3147,6 +3147,7 @@ static struct xprt_class xs_local_transport = {
.owner = THIS_MODULE,
.ident = XPRT_TRANSPORT_LOCAL,
.setup = xs_setup_local,
+ .netid = { "" },
};

static struct xprt_class xs_udp_transport = {
@@ -3155,6 +3156,7 @@ static struct xprt_class xs_udp_transport = {
.owner = THIS_MODULE,
.ident = XPRT_TRANSPORT_UDP,
.setup = xs_setup_udp,
+ .netid = { "udp", "udp6", "" },
};

static struct xprt_class xs_tcp_transport = {
@@ -3163,6 +3165,7 @@ static struct xprt_class xs_tcp_transport = {
.owner = THIS_MODULE,
.ident = XPRT_TRANSPORT_TCP,
.setup = xs_setup_tcp,
+ .netid = { "tcp", "tcp6", "" },
};

static struct xprt_class xs_bc_tcp_transport = {
@@ -3171,6 +3174,7 @@ static struct xprt_class xs_bc_tcp_transport = {
.owner = THIS_MODULE,
.ident = XPRT_TRANSPORT_BC_TCP,
.setup = xs_setup_bc_tcp,
+ .netid = { "" },
};

/**
--
2.27.0