tty: vt: split DEC CSI+h/l handling into csi_DEC_hl()

The DEC and ECMA handling of CSI+h/l is needlessly complicated. Split
these two, so that DEC is handled when the state is EPdec ('CSI ?' was
seen) and ECMA is handled in the EPecma state (no '?').
Signed-off-by: "Jiri Slaby (SUSE)" <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20240202065608.14019-5-jirislaby@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/vt.c

@@ -1874,20 +1874,13 @@ enum {
 	CSI_DEC_hl_MOUSE_VT200	= 1000,
 };
 
-enum {
-	CSI_hl_DISPLAY_CTRL	= 3,	/* handle ansi control chars */
-	CSI_hl_INSERT		= 4,	/* IRM: insert/replace */
-	CSI_hl_AUTO_NL		= 20,	/* LNM: Enter == CrLf/Lf */
-};
-
 /* console_lock is held */
-static void csi_hl(struct vc_data *vc, bool on_off)
+static void csi_DEC_hl(struct vc_data *vc, bool on_off)
 {
-	int i;
+	unsigned int i;
 
 	for (i = 0; i <= vc->vc_npar; i++)
-		if (vc->vc_priv == EPdec) {
-			switch(vc->vc_par[i]) {	/* DEC private modes set/reset */
+		switch (vc->vc_par[i]) {
 		case CSI_DEC_hl_CURSOR_KEYS:
 			if (on_off)
 				set_kbd(vc, decckm);
@@ -1904,8 +1897,7 @@ static void csi_hl(struct vc_data *vc, bool on_off)
 		case CSI_DEC_hl_REVERSE_VIDEO:
 			if (vc->vc_decscnm != on_off) {
 				vc->vc_decscnm = on_off;
-					invert_screen(vc, 0,
-							vc->vc_screenbuf_size,
+				invert_screen(vc, 0, vc->vc_screenbuf_size,
 					      false);
 				update_attr(vc);
 			}
@@ -1933,8 +1925,21 @@ static void csi_hl(struct vc_data *vc, bool on_off)
 			vc->vc_report_mouse = on_off ? 2 : 0;
 			break;
 		}
-		} else {
-			switch(vc->vc_par[i]) {	/* ANSI modes set/reset */
+}
+
+enum {
+	CSI_hl_DISPLAY_CTRL	= 3,	/* handle ansi control chars */
+	CSI_hl_INSERT		= 4,	/* IRM: insert/replace */
+	CSI_hl_AUTO_NL		= 20,	/* LNM: Enter == CrLf/Lf */
+};
+
+/* console_lock is held */
+static void csi_hl(struct vc_data *vc, bool on_off)
+{
+	unsigned int i;
+
+	for (i = 0; i <= vc->vc_npar; i++)
+		switch (vc->vc_par[i]) {	/* ANSI modes set/reset */
 		case CSI_hl_DISPLAY_CTRL:
 			vc->vc_disp_ctrl = on_off;
 			break;
@@ -1948,7 +1953,6 @@ static void csi_hl(struct vc_data *vc, bool on_off)
 				clr_kbd(vc, lnm);
 			break;
 		}
-		}
 }
 
 /* console_lock is held */
@@ -2379,12 +2383,12 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 		vc->vc_state = ESnormal;
 		switch(c) {
 		case 'h':
-			if (vc->vc_priv <= EPdec)
-				csi_hl(vc, true);
+			if (vc->vc_priv == EPdec)
+				csi_DEC_hl(vc, true);
 			return;
 		case 'l':
-			if (vc->vc_priv <= EPdec)
-				csi_hl(vc, false);
+			if (vc->vc_priv == EPdec)
+				csi_DEC_hl(vc, false);
 			return;
 		case 'c':
 			if (vc->vc_priv == EPdec) {
@@ -2494,6 +2498,12 @@ static void do_con_trol(struct tty_struct *tty, struct vc_data *vc, int c)
 			else if (vc->vc_par[0] == 3)
 				bitmap_zero(vc->vc_tab_stop, VC_TABSTOPS_COUNT);
 			return;
+		case 'h':
+			csi_hl(vc, true);
+			return;
+		case 'l':
+			csi_hl(vc, false);
+			return;
 		case 'm':
 			csi_m(vc);
 			return;