vt: make vc_data pointers const in selection.h

There are many functions declared in selection.h which only read from
struct vc_data passed as a parameter. Make all those uses const to hint
the compiler a bit.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200818085706.12163-1-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/vt/consolemap.c

@@ -268,7 +268,7 @@ unsigned short *set_translate(int m, struct vc_data *vc)
  *    was active.
  * Still, it is now possible to a certain extent to cut and paste non-ASCII.
  */
-u16 inverse_translate(struct vc_data *conp, int glyph, int use_unicode)
+u16 inverse_translate(const struct vc_data *conp, int glyph, int use_unicode)
 {
 	struct uni_pagedir *p;
 	int m;

drivers/tty/vt/vt.c

@@ -283,7 +283,8 @@ static inline bool con_should_update(const struct vc_data *vc)
 	return con_is_visible(vc) && !console_blanked;
 }
 
-static inline unsigned short *screenpos(struct vc_data *vc, int offset, int viewed)
+static inline unsigned short *screenpos(const struct vc_data *vc, int offset,
+		int viewed)
 {
 	unsigned short *p;
 	
@@ -543,7 +544,7 @@ int vc_uniscr_check(struct vc_data *vc)
  * This must be preceded by a successful call to vc_uniscr_check() once
  * the console lock has been taken.
  */
-void vc_uniscr_copy_line(struct vc_data *vc, void *dest, int viewed,
+void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, int viewed,
 			 unsigned int row, unsigned int col, unsigned int nr)
 {
 	struct uni_screen *uniscr = get_vc_uniscr(vc);
@@ -4740,7 +4741,7 @@ int con_font_op(struct vc_data *vc, struct console_font_op *op)
  */
 
 /* used by selection */
-u16 screen_glyph(struct vc_data *vc, int offset)
+u16 screen_glyph(const struct vc_data *vc, int offset)
 {
 	u16 w = scr_readw(screenpos(vc, offset, 1));
 	u16 c = w & 0xff;
@@ -4751,7 +4752,7 @@ u16 screen_glyph(struct vc_data *vc, int offset)
 }
 EXPORT_SYMBOL_GPL(screen_glyph);
 
-u32 screen_glyph_unicode(struct vc_data *vc, int n)
+u32 screen_glyph_unicode(const struct vc_data *vc, int n)
 {
 	struct uni_screen *uniscr = get_vc_uniscr(vc);
 
@@ -4762,13 +4763,13 @@ u32 screen_glyph_unicode(struct vc_data *vc, int n)
 EXPORT_SYMBOL_GPL(screen_glyph_unicode);
 
 /* used by vcs - note the word offset */
-unsigned short *screen_pos(struct vc_data *vc, int w_offset, int viewed)
+unsigned short *screen_pos(const struct vc_data *vc, int w_offset, int viewed)
 {
 	return screenpos(vc, 2 * w_offset, viewed);
 }
 EXPORT_SYMBOL_GPL(screen_pos);
 
-void getconsxy(struct vc_data *vc, unsigned char *p)
+void getconsxy(const struct vc_data *vc, unsigned char *p)
 {
 	/* clamp values if they don't fit */
 	p[0] = min(vc->state.x, 0xFFu);
@@ -4782,7 +4783,7 @@ void putconsxy(struct vc_data *vc, unsigned char *p)
 	set_cursor(vc);
 }
 
-u16 vcs_scr_readw(struct vc_data *vc, const u16 *org)
+u16 vcs_scr_readw(const struct vc_data *vc, const u16 *org)
 {
 	if ((unsigned long)org == vc->vc_pos && softcursor_original != -1)
 		return softcursor_original;

drivers/video/console/sticon.c

@@ -236,7 +236,7 @@ static int sticon_blank(struct vc_data *c, int blank, int mode_switch)
     return 1;
 }
 
-static u16 *sticon_screen_pos(struct vc_data *conp, int offset)
+static u16 *sticon_screen_pos(const struct vc_data *conp, int offset)
 {
     int line;
     unsigned long p;

drivers/video/fbdev/core/fbcon.c

@@ -2765,7 +2765,7 @@ static void fbcon_set_palette(struct vc_data *vc, const unsigned char *table)
 	fb_set_cmap(&palette_cmap, info);
 }
 
-static u16 *fbcon_screen_pos(struct vc_data *vc, int offset)
+static u16 *fbcon_screen_pos(const struct vc_data *vc, int offset)
 {
 	unsigned long p;
 	int line;

include/linux/console.h

@@ -74,7 +74,7 @@ struct consw {
 			enum vc_intensity intensity,
 			bool blink, bool underline, bool reverse, bool italic);
 	void	(*con_invert_region)(struct vc_data *vc, u16 *p, int count);
-	u16    *(*con_screen_pos)(struct vc_data *vc, int offset);
+	u16    *(*con_screen_pos)(const struct vc_data *vc, int offset);
 	unsigned long (*con_getxy)(struct vc_data *vc, unsigned long position,
 			int *px, int *py);
 	/*

include/linux/consolemap.h

@@ -17,7 +17,8 @@
 #ifdef CONFIG_CONSOLE_TRANSLATIONS
 struct vc_data;
 
-extern u16 inverse_translate(struct vc_data *conp, int glyph, int use_unicode);
+extern u16 inverse_translate(const struct vc_data *conp, int glyph,
+		int use_unicode);
 extern unsigned short *set_translate(int m, struct vc_data *vc);
 extern int conv_uni_to_pc(struct vc_data *conp, long ucs);
 extern u32 conv_8bit_to_uni(unsigned char c);

include/linux/selection.h

@@ -33,21 +33,23 @@ extern unsigned char default_red[];
 extern unsigned char default_grn[];
 extern unsigned char default_blu[];
 
-extern unsigned short *screen_pos(struct vc_data *vc, int w_offset, int viewed);
-extern u16 screen_glyph(struct vc_data *vc, int offset);
-extern u32 screen_glyph_unicode(struct vc_data *vc, int offset);
+extern unsigned short *screen_pos(const struct vc_data *vc, int w_offset,
+		int viewed);
+extern u16 screen_glyph(const struct vc_data *vc, int offset);
+extern u32 screen_glyph_unicode(const struct vc_data *vc, int offset);
 extern void complement_pos(struct vc_data *vc, int offset);
 extern void invert_screen(struct vc_data *vc, int offset, int count, int shift);
 
-extern void getconsxy(struct vc_data *vc, unsigned char *p);
+extern void getconsxy(const struct vc_data *vc, unsigned char *p);
 extern void putconsxy(struct vc_data *vc, unsigned char *p);
 
-extern u16 vcs_scr_readw(struct vc_data *vc, const u16 *org);
+extern u16 vcs_scr_readw(const struct vc_data *vc, const u16 *org);
 extern void vcs_scr_writew(struct vc_data *vc, u16 val, u16 *org);
 extern void vcs_scr_updated(struct vc_data *vc);
 
 extern int vc_uniscr_check(struct vc_data *vc);
-extern void vc_uniscr_copy_line(struct vc_data *vc, void *dest, int viewed,
+extern void vc_uniscr_copy_line(const struct vc_data *vc, void *dest,
+				int viewed,
 				unsigned int row, unsigned int col,
 				unsigned int nr);