cifs: add .splice_write

add splice_write support in cifs vfs using iter_file_splice_write
Signed-off-by: Andrés Souto <kai670@gmail.com>
Signed-off-by: Steve French <smfrench@gmail.com>

fs/cifs/cifsfs.c

@@ -1070,6 +1070,7 @@ const struct file_operations cifs_file_ops = {
 	.flush = cifs_flush,
 	.mmap  = cifs_file_mmap,
 	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
@@ -1088,6 +1089,7 @@ const struct file_operations cifs_file_strict_ops = {
 	.flush = cifs_flush,
 	.mmap = cifs_file_strict_mmap,
 	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
@@ -1107,6 +1109,7 @@ const struct file_operations cifs_file_direct_ops = {
 	.flush = cifs_flush,
 	.mmap = cifs_file_mmap,
 	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
 	.unlocked_ioctl  = cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
 	.clone_file_range = cifs_clone_file_range,
@@ -1124,6 +1127,7 @@ const struct file_operations cifs_file_nobrl_ops = {
 	.flush = cifs_flush,
 	.mmap  = cifs_file_mmap,
 	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
@@ -1141,6 +1145,7 @@ const struct file_operations cifs_file_strict_nobrl_ops = {
 	.flush = cifs_flush,
 	.mmap = cifs_file_strict_mmap,
 	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
 	.llseek = cifs_llseek,
 	.unlocked_ioctl	= cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
@@ -1159,6 +1164,7 @@ const struct file_operations cifs_file_direct_nobrl_ops = {
 	.flush = cifs_flush,
 	.mmap = cifs_file_mmap,
 	.splice_read = generic_file_splice_read,
+	.splice_write = iter_file_splice_write,
 	.unlocked_ioctl  = cifs_ioctl,
 	.copy_file_range = cifs_copy_file_range,
 	.clone_file_range = cifs_clone_file_range,