NFSD: Remove kmalloc from nfsd4_do_async_copy()

Instead of manufacturing a phony struct nfsd_file, pass the
struct file returned by nfs42_ssc_open() directly to
nfsd4_do_copy().
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/nfs4proc.c

@@ -1763,29 +1763,31 @@ static void cleanup_async_copy(struct nfsd4_copy *copy)
 	nfs4_put_copy(copy);
 }
 
+/**
+ * nfsd4_do_async_copy - kthread function for background server-side COPY
+ * @data: arguments for COPY operation
+ *
+ * Return values:
+ *   %0: Copy operation is done.
+ */
 static int nfsd4_do_async_copy(void *data)
 {
 	struct nfsd4_copy *copy = (struct nfsd4_copy *)data;
 	struct nfsd4_copy *cb_copy;
 
 	if (nfsd4_ssc_is_inter(copy)) {
-		copy->nf_src = kzalloc(sizeof(struct nfsd_file), GFP_KERNEL);
-		if (!copy->nf_src) {
-			copy->nfserr = nfserr_serverfault;
-			nfsd4_interssc_disconnect(copy->ss_mnt);
-			goto do_callback;
-		}
-		copy->nf_src->nf_file = nfs42_ssc_open(copy->ss_mnt, &copy->c_fh,
-					      &copy->stateid);
-		if (IS_ERR(copy->nf_src->nf_file)) {
+		struct file *filp;
+
+		filp = nfs42_ssc_open(copy->ss_mnt, &copy->c_fh,
+				      &copy->stateid);
+		if (IS_ERR(filp)) {
 			copy->nfserr = nfserr_offload_denied;
 			nfsd4_interssc_disconnect(copy->ss_mnt);
 			goto do_callback;
 		}
-		copy->nfserr = nfsd4_do_copy(copy, copy->nf_src->nf_file,
+		copy->nfserr = nfsd4_do_copy(copy, filp,
 					     copy->nf_dst->nf_file, false);
-		nfsd4_cleanup_inter_ssc(copy->ss_mnt, copy->nf_src->nf_file,
-					copy->nf_dst);
+		nfsd4_cleanup_inter_ssc(copy->ss_mnt, filp, copy->nf_dst);
 	} else {
 		copy->nfserr = nfsd4_do_copy(copy, copy->nf_src->nf_file,
 					     copy->nf_dst->nf_file, false);
@@ -1807,8 +1809,6 @@ static int nfsd4_do_async_copy(void *data)
 			      &copy->fh, copy->cp_count, copy->nfserr);
 	nfsd4_run_cb(&cb_copy->cp_cb);
 out:
-	if (nfsd4_ssc_is_inter(copy))
-		kfree(copy->nf_src);
 	cleanup_async_copy(copy);
 	return 0;
 }