NFSv4: Reduce the stack footprint of try_location()

Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4namespace.c

@@ -115,6 +115,7 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 				     char *page, char *page2,
 				     const struct nfs4_fs_location *location)
 {
+	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
 	struct vfsmount *mnt = ERR_PTR(-ENOENT);
 	char *mnt_path;
 	unsigned int maxbuflen;
@@ -126,9 +127,12 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 	mountdata->mnt_path = mnt_path;
 	maxbuflen = mnt_path - 1 - page2;
 
+	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
+	if (mountdata->addr == NULL)
+		return ERR_PTR(-ENOMEM);
+
 	for (s = 0; s < location->nservers; s++) {
 		const struct nfs4_string *buf = &location->servers[s];
-		struct sockaddr_storage addr;
 
 		if (buf->len <= 0 || buf->len >= maxbuflen)
 			continue;
@@ -137,11 +141,10 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 			continue;
 
 		mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
-				(struct sockaddr *)&addr, sizeof(addr));
+				mountdata->addr, addr_bufsize);
 		if (mountdata->addrlen == 0)
 			continue;
 
-		mountdata->addr = (struct sockaddr *)&addr;
 		rpc_set_port(mountdata->addr, NFS_PORT);
 
 		memcpy(page2, buf->data, buf->len);
@@ -156,6 +159,7 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
 		if (!IS_ERR(mnt))
 			break;
 	}
+	kfree(mountdata->addr);
 	return mnt;
 }