vt: make tc write more obvious in vc_con_write_normal

Nested ternary operators spread over 4 lines are really evil for
reading. Turn the outer one to proper 'if'. Now, we see, there is a
common path, so the code can be simplified. This way, the code is
understandable now.

Checked using symbolic execution (klee), that the old and new behaviors
are the same.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200615074910.19267-22-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 72ae8ede1ac950f106caac0c7e303a28db6b4706..4686f8b9251d3c8f77c7fc1cca8d16bad66a42a4 100644 (file)
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -2787,11 +2787,14 @@ static int vc_con_write_normal(struct vc_data *vc, int tc, int c,
                if (vc->vc_decim)
                        insert_char(vc, 1);
                vc_uniscr_putc(vc, next_c);
-               scr_writew(himask ?
-                            ((vc_attr << 8) & ~himask) +
-                            ((tc & 0x100) ? himask : 0) + (tc & 0xff) :
-                            (vc_attr << 8) + tc,
-                          (u16 *)vc->vc_pos);
+
+               if (himask)
+                       tc = ((tc & 0x100) ? himask : 0) |
+                             (tc &  0xff);
+               tc |= (vc_attr << 8) & ~himask;
+
+               scr_writew(tc, (u16 *)vc->vc_pos);
+
                if (con_should_update(vc) && draw->x < 0) {
                        draw->x = vc->state.x;
                        draw->from = vc->vc_pos;