2023-01-12 08:07:36

by Jiri Slaby

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) <[email protected]>
---
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

2023-01-12 10:12:35

by Ilpo Järvinen

Subject: Re: [PATCH 11/11] tty: vt: cache row count in con_scroll()

On Thu, 12 Jan 2023, Jiri Slaby (SUSE) wrote:

> It's used on few places, so make the code easier to follow by caching
> the subtraction result.
>
> Signed-off-by: Jiri Slaby (SUSE) <[email protected]>
> ---
> 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);
> }
>
>

Reviewed-by: Ilpo J?rvinen <[email protected]>

--
i.