SUNRPC: cleanup ida information when removing sunrpc module

After removing sunrpc module, I get many kmemleak information as,
unreferenced object 0xffff88003316b1e0 (size 544):
comm "gssproxy", pid 2148, jiffies 4294794465 (age 4200.081s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffffb0cfb58a>] kmemleak_alloc+0x4a/0xa0
[<ffffffffb03507fe>] kmem_cache_alloc+0x15e/0x1f0
[<ffffffffb0639baa>] ida_pre_get+0xaa/0x150
[<ffffffffb0639cfd>] ida_simple_get+0xad/0x180
[<ffffffffc06054fb>] nlmsvc_lookup_host+0x4ab/0x7f0 [lockd]
[<ffffffffc0605e1d>] lockd+0x4d/0x270 [lockd]
[<ffffffffc06061e5>] param_set_timeout+0x55/0x100 [lockd]
[<ffffffffc06cba24>] svc_defer+0x114/0x3f0 [sunrpc]
[<ffffffffc06cbbe7>] svc_defer+0x2d7/0x3f0 [sunrpc]
[<ffffffffc06c71da>] rpc_show_info+0x8a/0x110 [sunrpc]
[<ffffffffb044a33f>] proc_reg_write+0x7f/0xc0
[<ffffffffb038e41f>] __vfs_write+0xdf/0x3c0
[<ffffffffb0390f1f>] vfs_write+0xef/0x240
[<ffffffffb0392fbd>] SyS_write+0xad/0x130
[<ffffffffb0d06c37>] entry_SYSCALL_64_fastpath+0x1a/0xa9
[<ffffffffffffffff>] 0xffffffffffffffff

I found, the ida information (dynamic memory) isn't cleanup.

Signed-off-by: Kinglong Mee <[e-mail]>
Fixes: 2f048db4680a ("SUNRPC: Add an identifier for struct rpc_clnt")
Cc: [e-mail] # v3.12+
Signed-off-by: Trond Myklebust <[e-mail]>

include/linux/sunrpc/clnt.h

···
 void rpc_clnt_xprt_switch_add_xprt(struct rpc_clnt *, struct rpc_xprt *);
 bool rpc_clnt_xprt_switch_has_addr(struct rpc_clnt *clnt,
 			const struct sockaddr *sap);
+void rpc_cleanup_clids(void);
 #endif /* __KERNEL__ */
 #endif /* _LINUX_SUNRPC_CLNT_H */

net/sunrpc/clnt.c

···
 
 static DEFINE_IDA(rpc_clids);
 
+void rpc_cleanup_clids(void)
+{
+	ida_destroy(&rpc_clids);
+}
+
 static int rpc_alloc_clid(struct rpc_clnt *clnt)
 {
 	int clid;

net/sunrpc/sunrpc_syms.c

···
 static void __exit
 cleanup_sunrpc(void)
 {
+	rpc_cleanup_clids();
 	rpcauth_remove_module();
 	cleanup_socket_xprt();
 	svc_cleanup_xprt_sock();