[PATCH 06/11] tty: vt: remove struct uni_screen

Jiri Slaby (SUSE)
2023-01-12T08:02:48Z

It contains only lines with pointers to characters (u32s). So use
simple clear 'u32 **lines' all over the code.

This avoids zero-length arrays. It also makes the allocation less
error-prone (size of the struct wasn't taken into account at all).

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
drivers/tty/vt/vt.c | 117 ++++++++++++++++-----------------
include/linux/console_struct.h | 3 +-
2 files changed, 59 insertions(+), 61 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 86c18522231b..119b3eafef59 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -320,58 +320,55 @@ void schedule_console_callback(void)
* Our screen buffer is preceded by an array of line pointers so that
* scrolling only implies some pointer shuffling.
*/
-struct uni_screen {
- u32 *lines[0];
-};

-static struct uni_screen *vc_uniscr_alloc(unsigned int cols, unsigned int rows)
+static u32 **vc_uniscr_alloc(unsigned int cols, unsigned int rows)
{
- struct uni_screen *uniscr;
+ u32 **uni_lines;
void *p;
- unsigned int memsize, i, col_size = cols * sizeof(**uniscr->lines);
+ unsigned int memsize, i, col_size = cols * sizeof(**uni_lines);

/* allocate everything in one go */
memsize = col_size * rows;
- memsize += rows * sizeof(*uniscr->lines);
- p = vzalloc(memsize);
- if (!p)
+ memsize += rows * sizeof(*uni_lines);
+ uni_lines = vzalloc(memsize);
+ if (!uni_lines)
return NULL;

/* initial line pointers */
- uniscr = p;
- p = uniscr->lines + rows;
+ p = uni_lines + rows;
for (i = 0; i < rows; i++) {
- uniscr->lines[i] = p;
+ uni_lines[i] = p;
p += col_size;
}
- return uniscr;
+
+ return uni_lines;
}

-static void vc_uniscr_free(struct uni_screen *uniscr)
+static void vc_uniscr_free(u32 **uni_lines)
{
- vfree(uniscr);
+ vfree(uni_lines);
}

-static void vc_uniscr_set(struct vc_data *vc, struct uni_screen *new_uniscr)
+static void vc_uniscr_set(struct vc_data *vc, u32 **new_uni_lines)
{
- vc_uniscr_free(vc->vc_uni_screen);
- vc->vc_uni_screen = new_uniscr;
+ vc_uniscr_free(vc->vc_uni_lines);
+ vc->vc_uni_lines = new_uni_lines;
}

static void vc_uniscr_putc(struct vc_data *vc, u32 uc)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;

- if (uniscr)
- uniscr->lines[vc->state.y][vc->state.x] = uc;
+ if (uni_lines)
+ uni_lines[vc->state.y][vc->state.x] = uc;
}

static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;

- if (uniscr) {
- u32 *ln = uniscr->lines[vc->state.y];
+ if (uni_lines) {
+ u32 *ln = uni_lines[vc->state.y];
unsigned int x = vc->state.x, cols = vc->vc_cols;

memmove(&ln[x + nr], &ln[x], (cols - x - nr) * sizeof(*ln));
@@ -381,10 +378,10 @@ static void vc_uniscr_insert(struct vc_data *vc, unsigned int nr)

static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;

- if (uniscr) {
- u32 *ln = uniscr->lines[vc->state.y];
+ if (uni_lines) {
+ u32 *ln = uni_lines[vc->state.y];
unsigned int x = vc->state.x, cols = vc->vc_cols;

memcpy(&ln[x], &ln[x + nr], (cols - x - nr) * sizeof(*ln));
@@ -395,10 +392,10 @@ static void vc_uniscr_delete(struct vc_data *vc, unsigned int nr)
static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
unsigned int nr)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;

- if (uniscr) {
- u32 *ln = uniscr->lines[vc->state.y];
+ if (uni_lines) {
+ u32 *ln = uni_lines[vc->state.y];

memset32(&ln[x], ' ', nr);
}
@@ -407,22 +404,22 @@ static void vc_uniscr_clear_line(struct vc_data *vc, unsigned int x,
static void vc_uniscr_clear_lines(struct vc_data *vc, unsigned int y,
unsigned int nr)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;

- if (uniscr) {
+ if (uni_lines) {
unsigned int cols = vc->vc_cols;

while (nr--)
- memset32(uniscr->lines[y++], ' ', cols);
+ memset32(uni_lines[y++], ' ', cols);
}
}

static void vc_uniscr_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
enum con_scroll dir, unsigned int nr)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;

- if (uniscr) {
+ if (uni_lines) {
unsigned int i, j, k, sz, d, clear;

sz = b - t;
@@ -433,7 +430,7 @@ static void vc_uniscr_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
d = sz - nr;
}
for (i = 0; i < gcd(d, sz); i++) {
- u32 *tmp = uniscr->lines[t + i];
+ u32 *tmp = uni_lines[t + i];
j = i;
while (1) {
k = j + d;
@@ -441,31 +438,31 @@ static void vc_uniscr_scroll(struct vc_data *vc, unsigned int t, unsigned int b,
k -= sz;
if (k == i)
break;
- uniscr->lines[t + j] = uniscr->lines[t + k];
+ uni_lines[t + j] = uni_lines[t + k];
j = k;
}
- uniscr->lines[t + j] = tmp;
+ uni_lines[t + j] = tmp;
}
vc_uniscr_clear_lines(vc, clear, nr);
}
}

-static void vc_uniscr_copy_area(struct uni_screen *dst,
+static void vc_uniscr_copy_area(u32 **dst_lines,
unsigned int dst_cols,
unsigned int dst_rows,
- struct uni_screen *src,
+ u32 **src_lines,
unsigned int src_cols,
unsigned int src_top_row,
unsigned int src_bot_row)
{
unsigned int dst_row = 0;

- if (!dst)
+ if (!dst_lines)
return;

while (src_top_row < src_bot_row) {
- u32 *src_line = src->lines[src_top_row];
- u32 *dst_line = dst->lines[dst_row];
+ u32 *src_line = src_lines[src_top_row];
+ u32 *dst_line = dst_lines[dst_row];

memcpy(dst_line, src_line, src_cols * sizeof(*src_line));
if (dst_cols - src_cols)
@@ -474,7 +471,7 @@ static void vc_uniscr_copy_area(struct uni_screen *dst,
dst_row++;
}
while (dst_row < dst_rows) {
- u32 *dst_line = dst->lines[dst_row];
+ u32 *dst_line = dst_lines[dst_row];

memset32(dst_line, ' ', dst_cols);
dst_row++;
@@ -489,7 +486,7 @@ static void vc_uniscr_copy_area(struct uni_screen *dst,
*/
int vc_uniscr_check(struct vc_data *vc)
{
- struct uni_screen *uniscr;
+ u32 **uni_lines;
unsigned short *p;
int x, y, mask;

@@ -498,11 +495,11 @@ int vc_uniscr_check(struct vc_data *vc)
if (!vc->vc_utf)
return -ENODATA;

- if (vc->vc_uni_screen)
+ if (vc->vc_uni_lines)
return 0;

- uniscr = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);
- if (!uniscr)
+ uni_lines = vc_uniscr_alloc(vc->vc_cols, vc->vc_rows);
+ if (!uni_lines)
return -ENOMEM;

/*
@@ -514,14 +511,15 @@ int vc_uniscr_check(struct vc_data *vc)
p = (unsigned short *)vc->vc_origin;
mask = vc->vc_hi_font_mask | 0xff;
for (y = 0; y < vc->vc_rows; y++) {
- u32 *line = uniscr->lines[y];
+ u32 *line = uni_lines[y];
for (x = 0; x < vc->vc_cols; x++) {
u16 glyph = scr_readw(p++) & mask;
line[x] = inverse_translate(vc, glyph, true);
}
}

- vc->vc_uni_screen = uniscr;
+ vc->vc_uni_lines = uni_lines;
+
return 0;
}

@@ -533,11 +531,11 @@ int vc_uniscr_check(struct vc_data *vc)
void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, bool viewed,
unsigned int row, unsigned int col, unsigned int nr)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;
int offset = row * vc->vc_size_row + col * 2;
unsigned long pos;

- BUG_ON(!uniscr);
+ BUG_ON(!uni_lines);

pos = (unsigned long)screenpos(vc, offset, viewed);
if (pos >= vc->vc_origin && pos < vc->vc_scr_end) {
@@ -548,7 +546,7 @@ void vc_uniscr_copy_line(const struct vc_data *vc, void *dest, bool viewed,
*/
row = (pos - vc->vc_origin) / vc->vc_size_row;
col = ((pos - vc->vc_origin) % vc->vc_size_row) / 2;
- memcpy(dest, &uniscr->lines[row][col], nr * sizeof(u32));
+ memcpy(dest, &uni_lines[row][col], nr * sizeof(u32));
} else {
/*
* Scrollback is active. For now let's simply backtranslate
@@ -1150,7 +1148,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
unsigned int new_cols, new_rows, new_row_size, new_screen_size;
unsigned int user;
unsigned short *oldscreen, *newscreen;
- struct uni_screen *new_uniscr = NULL;
+ u32 **new_uniscr = NULL;

WARN_CONSOLE_UNLOCKED();

@@ -1194,7 +1192,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
if (!newscreen)
return -ENOMEM;

- if (vc->vc_uni_screen) {
+ if (vc->vc_uni_lines) {
new_uniscr = vc_uniscr_alloc(new_cols, new_rows);
if (!new_uniscr) {
kfree(newscreen);
@@ -1246,7 +1244,7 @@ static int vc_do_resize(struct tty_struct *tty, struct vc_data *vc,
end = old_origin + old_row_size * min(old_rows, new_rows);

vc_uniscr_copy_area(new_uniscr, new_cols, new_rows,
- vc->vc_uni_screen, rlth/2, first_copied_row,
+ vc->vc_uni_lines, rlth/2, first_copied_row,
min(old_rows, new_rows));
vc_uniscr_set(vc, new_uniscr);

@@ -4688,10 +4686,11 @@ EXPORT_SYMBOL_GPL(screen_glyph);

u32 screen_glyph_unicode(const struct vc_data *vc, int n)
{
- struct uni_screen *uniscr = vc->vc_uni_screen;
+ u32 **uni_lines = vc->vc_uni_lines;
+
+ if (uni_lines)
+ return uni_lines[n / vc->vc_cols][n % vc->vc_cols];

- if (uniscr)
- return uniscr->lines[n / vc->vc_cols][n % vc->vc_cols];
return inverse_translate(vc, screen_glyph(vc, n * 2), true);
}
EXPORT_SYMBOL_GPL(screen_glyph_unicode);
diff --git a/include/linux/console_struct.h b/include/linux/console_struct.h
index 1518568aaf0f..539f1cd45309 100644
--- a/include/linux/console_struct.h
+++ b/include/linux/console_struct.h
@@ -18,7 +18,6 @@
#include <linux/workqueue.h>

struct uni_pagedict;
-struct uni_screen;

#define NPAR 16
#define VC_TABSTOPS_COUNT 256U
@@ -159,7 +158,7 @@ struct vc_data {
struct vc_data **vc_display_fg; /* [!] Ptr to var holding fg console for this display */
struct uni_pagedict *uni_pagedict;
struct uni_pagedict **uni_pagedict_loc; /* [!] Location of uni_pagedict variable for this console */
- struct uni_screen *vc_uni_screen; /* unicode screen content */
+ u32 **vc_uni_lines; /* unicode screen content */
/* additional information is in vt_kern.h */
};

--
2.39.0