linux-kernel - [PATCH 6/7] tty/vt: consolemap: improve UNI

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Date:   Tue, 14 Jun 2022 09:57:12 +0200
From:   Jiri Slaby <jslaby@...e.cz>
To:     gregkh@...uxfoundation.org
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jiri Slaby <jslaby@...e.cz>,
        Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: [PATCH 6/7] tty/vt: consolemap: improve UNI_*() macros definitions

Use FIELD_GET() and GENMASK() helpers instead of direct shifts and ANDs.
This makes the code even more obvious. I didn't know about the helpers
at the time of writing the macros.

Suggested-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
---
 drivers/tty/vt/consolemap.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 16d0d8f04f0e..9e94ec0e0f83 100644
--- a/drivers/tty/vt/consolemap.c
+++ b/drivers/tty/vt/consolemap.c
@@ -23,6 +23,8 @@
  * stack overflow.
  */
 
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/module.h>
 #include <linux/kd.h>
 #include <linux/errno.h>
@@ -190,10 +192,17 @@ static enum translation_map inv_translate[MAX_NR_CONSOLES];
 #define UNI_DIR_ROWS	32U
 #define UNI_ROW_GLYPHS	64U
 
-#define UNI_DIR(uni)		( (uni)                   >> 11)
-#define UNI_ROW(uni)		(((uni) & GENMASK(10, 6)) >>  6)
-#define UNI_GLYPH(uni)		( (uni) & GENMASK( 5, 0))
-#define UNI(dir, row, glyph)	(((dir) << 11) | ((row) << 6) | (glyph))
+#define UNI_DIR_BITS		GENMASK(15, 11)
+#define UNI_ROW_BITS		GENMASK(10,  6)
+#define UNI_GLYPH_BITS		GENMASK( 5,  0)
+
+#define UNI_DIR(uni)		FIELD_GET(UNI_DIR_BITS, (uni))
+#define UNI_ROW(uni)		FIELD_GET(UNI_ROW_BITS, (uni))
+#define UNI_GLYPH(uni)		FIELD_GET(UNI_GLYPH_BITS, (uni))
+
+#define UNI(dir, row, glyph)	(FIELD_PREP(UNI_DIR_BITS, (dir)) | \
+				 FIELD_PREP(UNI_ROW_BITS, (row)) | \
+				 FIELD_PREP(UNI_GLYPH_BITS, (glyph)))
 
 /**
  * struct uni_pagedict -- unicode directory
-- 
2.36.1