linux-kernel - [PATCH v2 13/47] use clamp() for counts in csi

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Date: Mon, 22 Jan 2024 12:03:27 +0100
From: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To: gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	"Jiri Slaby (SUSE)" <jirislaby@...nel.org>
Subject: [PATCH v2 13/47] use clamp() for counts in csi_?() handlers

The count to process is supposed to be between 1 and vc->vc_cols -
vc->state.x (or rows and .y). clamp() can be used exactly for this,
instead of ifs and min().

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---

Notes:
    [v2] new in v2.

 drivers/tty/vt/vt.c | 27 +++++----------------------
 1 file changed, 5 insertions(+), 22 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index bf77d962eeb4..05baf9ca23f2 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1574,12 +1574,7 @@ static void csi_K(struct vc_data *vc, int vpar)
 /* erase the following vpar positions */
 static void csi_X(struct vc_data *vc, unsigned int vpar)
 {					  /* not vt100? */
-	unsigned int count;
-
-	if (!vpar)
-		vpar++;
-
-	count = min(vpar, vc->vc_cols - vc->state.x);
+	unsigned int count = clamp(vpar, 1, vc->vc_cols - vc->state.x);
 
 	vc_uniscr_clear_line(vc, vc->state.x, count);
 	scr_memsetw((unsigned short *)vc->vc_pos, vc->vc_video_erase_char, 2 * count);
@@ -2010,20 +2005,14 @@ static void setterm_command(struct vc_data *vc)
 /* console_lock is held */
 static void csi_at(struct vc_data *vc, unsigned int nr)
 {
-	if (nr > vc->vc_cols - vc->state.x)
-		nr = vc->vc_cols - vc->state.x;
-	else if (!nr)
-		nr = 1;
+	nr = clamp(nr, 1, vc->vc_cols - vc->state.x);
 	insert_char(vc, nr);
 }
 
 /* console_lock is held */
 static void csi_L(struct vc_data *vc, unsigned int nr)
 {
-	if (nr > vc->vc_rows - vc->state.y)
-		nr = vc->vc_rows - vc->state.y;
-	else if (!nr)
-		nr = 1;
+	nr = clamp(nr, 1, vc->vc_rows - vc->state.y);
 	con_scroll(vc, vc->state.y, vc->vc_bottom, SM_DOWN, nr);
 	vc->vc_need_wrap = 0;
 }
@@ -2031,20 +2020,14 @@ static void csi_L(struct vc_data *vc, unsigned int nr)
 /* console_lock is held */
 static void csi_P(struct vc_data *vc, unsigned int nr)
 {
-	if (nr > vc->vc_cols - vc->state.x)
-		nr = vc->vc_cols - vc->state.x;
-	else if (!nr)
-		nr = 1;
+	nr = clamp(nr, 1, vc->vc_cols - vc->state.x);
 	delete_char(vc, nr);
 }
 
 /* console_lock is held */
 static void csi_M(struct vc_data *vc, unsigned int nr)
 {
-	if (nr > vc->vc_rows - vc->state.y)
-		nr = vc->vc_rows - vc->state.y;
-	else if (!nr)
-		nr=1;
+	nr = clamp(nr, 1, vc->vc_rows - vc->state.y);
 	con_scroll(vc, vc->state.y, vc->vc_bottom, SM_UP, nr);
 	vc->vc_need_wrap = 0;
 }
-- 
2.43.0