linux-kernel - [PATCH 21/45] tty: vt: remove checks for count in consw::con

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Date: Thu, 18 Jan 2024 08:57:32 +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>,
	Helge Deller <deller@....de>,
	"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
	linux-fbdev@...r.kernel.org,
	dri-devel@...ts.freedesktop.org,
	linux-parisc@...r.kernel.org
Subject: [PATCH 21/45] tty: vt: remove checks for count in consw::con_clear() implementations

'count' in consw::con_clear() is guaranteed to be positive. csi_X() (the
only caller) takes the minimum of the vc parameter (which is at least 1)
and count of characters till the end of the line. The latter is computed
as a subtraction of vc->vc_cols (count) and vc->state.x (offset). So for
the worst case, full line, it is 1.

Therefore, there is no point in checking zero or negative values (width
is now unsigned anyway).

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
Cc: Helge Deller <deller@....de>
Cc: "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>
Cc: linux-fbdev@...r.kernel.org
Cc: dri-devel@...ts.freedesktop.org
Cc: linux-parisc@...r.kernel.org
---
 drivers/video/console/mdacon.c | 3 ---
 drivers/video/console/sticon.c | 3 ---
 2 files changed, 6 deletions(-)

diff --git a/drivers/video/console/mdacon.c b/drivers/video/console/mdacon.c
index 1ddbb6cd5b0c..2ff2c9394d40 100644
--- a/drivers/video/console/mdacon.c
+++ b/drivers/video/console/mdacon.c
@@ -448,9 +448,6 @@ static void mdacon_clear(struct vc_data *c, unsigned int y, unsigned int x,
 	u16 *dest = mda_addr(x, y);
 	u16 eattr = mda_convert_attr(c->vc_video_erase_char);
 
-	if (width <= 0)
-		return;
-
 	scr_memsetw(dest, eattr, width * 2);
 }
 
diff --git a/drivers/video/console/sticon.c b/drivers/video/console/sticon.c
index d99c2a659bfd..b1d972d9a31c 100644
--- a/drivers/video/console/sticon.c
+++ b/drivers/video/console/sticon.c
@@ -303,9 +303,6 @@ static void sticon_deinit(struct vc_data *c)
 static void sticon_clear(struct vc_data *conp, unsigned int sy, unsigned int sx,
 			 unsigned int width)
 {
-    if (!width)
-	return;
-
     sti_clear(sticon_sti, sy, sx, 1, width,
 	      conp->vc_video_erase_char, font_data[conp->vc_num]);
 }
-- 
2.43.0