From: Herbert Xu <herbert@gondor.apana.org.au>
The following patch adds basic module reference counting to vt console
drivers. Currently modules like fbcon are not counted at all.
---
25-akpm/drivers/char/vt.c | 29 ++++++++++++++++++++++++----
25-akpm/drivers/video/console/dummycon.c | 2 +
25-akpm/drivers/video/console/fbcon.c | 12 ++++++++---
25-akpm/drivers/video/console/mdacon.c | 8 +------
25-akpm/drivers/video/console/newport_con.c | 5 +---
25-akpm/drivers/video/console/promcon.c | 1
25-akpm/drivers/video/console/sticon.c | 3 +-
25-akpm/drivers/video/console/vgacon.c | 1
25-akpm/include/linux/console.h | 4 ++-
9 files changed, 47 insertions(+), 18 deletions(-)
diff -puN drivers/char/vt.c~module-ref-counting-for-vt-console-drivers drivers/char/vt.c
--- 25/drivers/char/vt.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/char/vt.c Thu Apr 29 15:51:32 2004
@@ -661,11 +661,14 @@ int vc_cons_allocated(unsigned int i)
static void visual_init(int currcons, int init)
{
/* ++Geert: sw->con_init determines console size */
+ if (sw)
+ module_put(sw->owner);
sw = conswitchp;
#ifndef VT_SINGLE_DRIVER
if (con_driver_map[currcons])
sw = con_driver_map[currcons];
#endif
+ __module_get(sw->owner);
cons_num = currcons;
display_fg = &master_display_fg;
vc_cons[currcons].d->vc_uni_pagedir_loc = &vc_cons[currcons].d->vc_uni_pagedir;
@@ -2668,25 +2671,38 @@ static void clear_buffer_attributes(int
* and become default driver for newly opened ones.
*/
-void take_over_console(const struct consw *csw, int first, int last, int deflt)
+int take_over_console(const struct consw *csw, int first, int last, int deflt)
{
int i, j = -1;
const char *desc;
+ struct module *owner;
+
+ owner = csw->owner;
+ if (!try_module_get(owner))
+ return -ENODEV;
acquire_console_sem();
desc = csw->con_startup();
if (!desc) {
release_console_sem();
- return;
+ module_put(owner);
+ return -ENODEV;
}
- if (deflt)
+ if (deflt) {
+ if (conswitchp)
+ module_put(conswitchp->owner);
+ __module_get(owner);
conswitchp = csw;
+ }
for (i = first; i <= last; i++) {
int old_was_color;
int currcons = i;
+ if (con_driver_map[i])
+ module_put(con_driver_map[i]->owner);
+ __module_get(owner);
con_driver_map[i] = csw;
if (!vc_cons[i].d || !vc_cons[i].d->vc_sw)
@@ -2721,6 +2737,9 @@ void take_over_console(const struct cons
printk("to %s\n", desc);
release_console_sem();
+
+ module_put(owner);
+ return 0;
}
void give_up_console(const struct consw *csw)
@@ -2728,8 +2747,10 @@ void give_up_console(const struct consw
int i;
for(i = 0; i < MAX_NR_CONSOLES; i++)
- if (con_driver_map[i] == csw)
+ if (con_driver_map[i] == csw) {
+ module_put(csw->owner);
con_driver_map[i] = NULL;
+ }
}
#endif
diff -puN drivers/video/console/dummycon.c~module-ref-counting-for-vt-console-drivers drivers/video/console/dummycon.c
--- 25/drivers/video/console/dummycon.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/dummycon.c Thu Apr 29 15:51:32 2004
@@ -11,6 +11,7 @@
#include <linux/console.h>
#include <linux/vt_kern.h>
#include <linux/init.h>
+#include <linux/module.h>
/*
* Dummy console driver
@@ -58,6 +59,7 @@ static int dummycon_dummy(void)
*/
const struct consw dummy_con = {
+ .owner = THIS_MODULE,
.con_startup = dummycon_startup,
.con_init = dummycon_init,
.con_deinit = DUMMY,
diff -puN drivers/video/console/fbcon.c~module-ref-counting-for-vt-console-drivers drivers/video/console/fbcon.c
--- 25/drivers/video/console/fbcon.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/fbcon.c Thu Apr 29 15:51:32 2004
@@ -304,8 +304,7 @@ int set_con2fb_map(int unit, int newidx)
return -ENODEV;
con2fb_map[unit] = newidx;
fbcon_is_default = (vc->vc_sw == &fb_con) ? 1 : 0;
- take_over_console(&fb_con, unit, unit, fbcon_is_default);
- return 0;
+ return take_over_console(&fb_con, unit, unit, fbcon_is_default);
}
/*
@@ -2240,6 +2239,7 @@ static int fbcon_event_notify(struct not
*/
const struct consw fb_con = {
+ .owner = THIS_MODULE,
.con_startup = fbcon_startup,
.con_init = fbcon_init,
.con_deinit = fbcon_deinit,
@@ -2269,10 +2269,16 @@ static int fbcon_event_notifier_register
int __init fb_console_init(void)
{
+ int err;
+
if (!num_registered_fb)
return -ENODEV;
- take_over_console(&fb_con, first_fb_vc, last_fb_vc, fbcon_is_default);
+ err = take_over_console(&fb_con, first_fb_vc, last_fb_vc,
+ fbcon_is_default);
+ if (err)
+ return err;
+
acquire_console_sem();
if (!fbcon_event_notifier_registered) {
fb_register_client(&fbcon_event_notifer);
diff -puN drivers/video/console/mdacon.c~module-ref-counting-for-vt-console-drivers drivers/video/console/mdacon.c
--- 25/drivers/video/console/mdacon.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/mdacon.c Thu Apr 29 15:51:32 2004
@@ -370,8 +370,6 @@ static void mdacon_init(struct vc_data *
if (mda_display_fg == NULL)
mda_display_fg = c;
-
- MOD_INC_USE_COUNT;
}
static void mdacon_deinit(struct vc_data *c)
@@ -380,8 +378,6 @@ static void mdacon_deinit(struct vc_data
if (mda_display_fg == c)
mda_display_fg = NULL;
-
- MOD_DEC_USE_COUNT;
}
static inline u16 mda_convert_attr(u16 ch)
@@ -586,6 +582,7 @@ static int mdacon_scroll(struct vc_data
*/
const struct consw mda_con = {
+ .owner = THIS_MODULE,
.con_startup = mdacon_startup,
.con_init = mdacon_init,
.con_deinit = mdacon_deinit,
@@ -609,8 +606,7 @@ int __init mda_console_init(void)
if (mda_first_vc > mda_last_vc)
return 1;
- take_over_console(&mda_con, mda_first_vc-1, mda_last_vc-1, 0);
- return 0;
+ return take_over_console(&mda_con, mda_first_vc-1, mda_last_vc-1, 0);
}
void __exit mda_console_exit(void)
diff -puN drivers/video/console/newport_con.c~module-ref-counting-for-vt-console-drivers drivers/video/console/newport_con.c
--- 25/drivers/video/console/newport_con.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/newport_con.c Thu Apr 29 15:53:24 2004
@@ -705,6 +705,7 @@ static int newport_dummy(struct vc_data
#define DUMMY (void *) newport_dummy
const struct consw newport_con = {
+ .owner = THIS_MODULE,
.con_startup = newport_startup,
.con_init = newport_init,
.con_deinit = newport_deinit,
@@ -726,9 +727,7 @@ const struct consw newport_con = {
#ifdef MODULE
static int __init newport_console_init(void)
{
- take_over_console(&newport_con, 0, MAX_NR_CONSOLES - 1, 1);
-
- return 0;
+ return take_over_console(&newport_con, 0, MAX_NR_CONSOLES - 1, 1);
}
static void __exit newport_console_exit(void)
diff -puN drivers/video/console/promcon.c~module-ref-counting-for-vt-console-drivers drivers/video/console/promcon.c
--- 25/drivers/video/console/promcon.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/promcon.c Thu Apr 29 15:51:32 2004
@@ -574,6 +574,7 @@ static int promcon_dummy(void)
#define DUMMY (void *) promcon_dummy
const struct consw prom_con = {
+ .owner = THIS_MODULE,
.con_startup = promcon_startup,
.con_init = promcon_init,
.con_deinit = promcon_deinit,
diff -puN drivers/video/console/sticon.c~module-ref-counting-for-vt-console-drivers drivers/video/console/sticon.c
--- 25/drivers/video/console/sticon.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/sticon.c Thu Apr 29 15:51:32 2004
@@ -354,6 +354,7 @@ static void sticon_save_screen(struct vc
}
static struct consw sti_con = {
+ .owner = THIS_MODULE,
.con_startup = sticon_startup,
.con_init = sticon_init,
.con_deinit = sticon_deinit,
@@ -390,7 +391,7 @@ int __init sticonsole_init(void)
if (conswitchp == &dummy_con) {
printk(KERN_INFO "sticon: Initializing STI text console.\n");
- take_over_console(&sti_con, 0, MAX_NR_CONSOLES - 1, 1);
+ return take_over_console(&sti_con, 0, MAX_NR_CONSOLES - 1, 1);
}
return 0;
}
diff -puN drivers/video/console/vgacon.c~module-ref-counting-for-vt-console-drivers drivers/video/console/vgacon.c
--- 25/drivers/video/console/vgacon.c~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/drivers/video/console/vgacon.c Thu Apr 29 15:51:32 2004
@@ -1065,6 +1065,7 @@ static int vgacon_dummy(struct vc_data *
#define DUMMY (void *) vgacon_dummy
const struct consw vga_con = {
+ .owner = THIS_MODULE,
.con_startup = vgacon_startup,
.con_init = vgacon_init,
.con_deinit = vgacon_deinit,
diff -puN include/linux/console.h~module-ref-counting-for-vt-console-drivers include/linux/console.h
--- 25/include/linux/console.h~module-ref-counting-for-vt-console-drivers Thu Apr 29 15:51:32 2004
+++ 25-akpm/include/linux/console.h Thu Apr 29 15:51:32 2004
@@ -19,6 +19,7 @@
struct vc_data;
struct console_font_op;
+struct module;
/*
* this is what the terminal answers to a ESC-Z or csi0c query.
@@ -27,6 +28,7 @@ struct console_font_op;
#define VT102ID "\033[?6c"
struct consw {
+ struct module *owner;
const char *(*con_startup)(void);
void (*con_init)(struct vc_data *, int);
void (*con_deinit)(struct vc_data *);
@@ -58,7 +60,7 @@ extern const struct consw vga_con; /* VG
extern const struct consw newport_con; /* SGI Newport console */
extern const struct consw prom_con; /* SPARC PROM console */
-void take_over_console(const struct consw *sw, int first, int last, int deflt);
+int take_over_console(const struct consw *sw, int first, int last, int deflt);
void give_up_console(const struct consw *sw);
/* scroll */
_