This fixes a panic doing the first READDIR or READDIRPLUS call when:

* the client is ia64 or any platform that actually implements
flush_dcache_page(), and

* the server returns fsinfo.dtpref >= client's PAGE_SIZE, and

* the server does *not* return post-op attributes for the directory
in the READDIR reply.

Problem diagnosed by Greg Banks <[e-mail]>

Signed-off-by: Trond Myklebust <[e-mail]>

net/sunrpc/xdr.c

···
 	do {
 		/* Are any pointers crossing a page boundary? */
 		if (pgto_base == 0) {
-			flush_dcache_page(*pgto);
 			pgto_base = PAGE_CACHE_SIZE;
 			pgto--;
 		}
···
 		vto = kmap_atomic(*pgto, KM_USER0);
 		vfrom = kmap_atomic(*pgfrom, KM_USER1);
 		memmove(vto + pgto_base, vfrom + pgfrom_base, copy);
+		flush_dcache_page(*pgto);
 		kunmap_atomic(vfrom, KM_USER1);
 		kunmap_atomic(vto, KM_USER0);
 
 	} while ((len -= copy) != 0);
-	flush_dcache_page(*pgto);
 }
 
 /*