linux-kernel - [PATCH 11/11] tty: vt: cache row count in con

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Message-Id: <20230112080136.4929-11-jirislaby@kernel.org>
Date:   Thu, 12 Jan 2023 09:01:36 +0100
From:   "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To:     gregkh@...uxfoundation.org
Cc:     Kees Cook <keescook@...omium.org>, linux-serial@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
Subject: [PATCH 11/11] tty: vt: cache row count in con_scroll()

It's used on few places, so make the code easier to follow by caching
the subtraction result.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
 drivers/tty/vt/vt.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 165c81211bdc..671304b31f9f 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -561,10 +561,11 @@ static void con_scroll(struct vc_data *vc, unsigned int top,
 		       unsigned int bottom, enum con_scroll dir,
 		       unsigned int nr)
 {
+	unsigned int rows = bottom - top;
 	u16 *clear, *dst, *src;
 
 	if (top + nr >= bottom)
-		nr = bottom - top - 1;
+		nr = rows - 1;
 	if (bottom > vc->vc_rows || top >= bottom || nr < 1)
 		return;
 
@@ -577,10 +578,10 @@ static void con_scroll(struct vc_data *vc, unsigned int top,
 	dst = (u16 *)(vc->vc_origin + vc->vc_size_row * (top + nr));
 
 	if (dir == SM_UP) {
-		clear = src + (bottom - top - nr) * vc->vc_cols;
+		clear = src + (rows - nr) * vc->vc_cols;
 		swap(src, dst);
 	}
-	scr_memmovew(dst, src, (bottom - top - nr) * vc->vc_size_row);
+	scr_memmovew(dst, src, (rows - nr) * vc->vc_size_row);
 	scr_memsetw(clear, vc->vc_video_erase_char, vc->vc_size_row * nr);
 }
 
-- 
2.39.0