afs: Fix fall-through warnings for Clang

In preparation to enable -Wimplicit-fallthrough for Clang, fix multiple
warnings by explicitly adding multiple fallthrough pseudo-keywords in
places where the code is intended to fall through to the next case.

Link: https://github.com/KSPP/linux/issues/115
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jeffrey Altman <jaltman@auristor.com>
cc: linux-afs@lists.infradead.org
cc: linux-hardening@vger.kernel.org
Link: https://lore.kernel.org/r/51150b54e0b0431a2c401cd54f2c4e7f50e94601.1605896059.git.gustavoars@kernel.org/ # v1
Link: https://lore.kernel.org/r/20210420211615.GA51432@embeddedor/ # v2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/afs/cmservice.c

@@ -322,6 +322,8 @@ static int afs_deliver_cb_callback(struct afs_call *call)
 			return ret;
 
 		call->unmarshall++;
+		fallthrough;
+
 	case 5:
 		break;
 	}
@@ -418,6 +420,7 @@ static int afs_deliver_cb_init_call_back_state3(struct afs_call *call)
 			r->node[loop] = ntohl(b[loop + 5]);
 
 		call->unmarshall++;
+		fallthrough;
 
 	case 2:
 		break;
@@ -530,6 +533,7 @@ static int afs_deliver_cb_probe_uuid(struct afs_call *call)
 			r->node[loop] = ntohl(b[loop + 5]);
 
 		call->unmarshall++;
+		fallthrough;
 
 	case 2:
 		break;
@@ -663,6 +667,7 @@ static int afs_deliver_yfs_cb_callback(struct afs_call *call)
 
 		afs_extract_to_tmp(call);
 		call->unmarshall++;
+		fallthrough;
 
 	case 3:
 		break;

fs/afs/fsclient.c

@@ -388,6 +388,7 @@ static int afs_deliver_fs_fetch_data(struct afs_call *call)
 		req->file_size = vp->scb.status.size;
 
 		call->unmarshall++;
+		fallthrough;
 
 	case 5:
 		break;
@@ -1408,6 +1409,7 @@ static int afs_deliver_fs_get_volume_status(struct afs_call *call)
 		_debug("motd '%s'", p);
 
 		call->unmarshall++;
+		fallthrough;
 
 	case 8:
 		break;
@@ -1845,6 +1847,7 @@ static int afs_deliver_fs_inline_bulk_status(struct afs_call *call)
 		xdr_decode_AFSVolSync(&bp, &op->volsync);
 
 		call->unmarshall++;
+		fallthrough;
 
 	case 6:
 		break;
@@ -1979,6 +1982,7 @@ static int afs_deliver_fs_fetch_acl(struct afs_call *call)
 		xdr_decode_AFSVolSync(&bp, &op->volsync);
 
 		call->unmarshall++;
+		fallthrough;
 
 	case 4:
 		break;

fs/afs/vlclient.c

@@ -593,6 +593,7 @@ static int afs_deliver_yfsvl_get_endpoints(struct afs_call *call)
 		if (ret < 0)
 			return ret;
 		call->unmarshall = 6;
+		fallthrough;
 
 	case 6:
 		break;