Commit 9bccd264 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

SUNRPC: Close a race with transport setup and module put 



After we've looked up the transport module, we need to ensure it can't
go away until we've finished running the transport setup code.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent d5aa6b22

net/sunrpc/xprt.c

+33 −11
Original line number Diff line number Diff line
@@ -157,6 +157,32 @@ xprt_class_release(const struct xprt_class *t) 
	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;



	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)

{
@@ -1929,21 +1955,17 @@ 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;

		}

	}

	spin_unlock(&xprt_list_lock);

	t = xprt_class_find_by_ident(args->ident);

	if (!t) {

		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)