[PATCH 11/21] fbcon: Extract fbcon_open/release helpers

Daniel Vetter
2022-01-31T21:07:12Z

There's two minor behaviour changes in here:
- in error paths we now consistently call fb_ops->fb_release
- fb_release really can't fail (fbmem.c ignores it too) and there's no
reasonable cleanup we can do anyway.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Claudio Suarez <cssk@net-c.es>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Du Cheng <ducheng2@gmail.com>
---
drivers/video/fbdev/core/fbcon.c | 107 +++++++++++++++----------------
1 file changed, 53 insertions(+), 54 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index fa30e1909164..eea2ee14b64c 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -680,19 +680,37 @@ static int fbcon_invalid_charcount(struct fb_info *info, unsigned charcount)

#endif /* CONFIG_MISC_TILEBLITTING */

+static int fbcon_open(struct fb_info *info)
+{
+ if (!try_module_get(info->fbops->owner))
+ return -ENODEV;
+
+ if (info->fbops->fb_open &&
+ info->fbops->fb_open(info, 0)) {
+ module_put(info->fbops->owner);
+ return -ENODEV;
+ }
+
+ return 0;
+}
+
+static void fbcon_release(struct fb_info *info)
+{
+ if (info->fbops->fb_release)
+ info->fbops->fb_release(info, 0);
+
+ module_put(info->fbops->owner);
+}

static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
int unit, int oldidx)
{
struct fbcon_ops *ops = NULL;
- int err = 0;
-
- if (!try_module_get(info->fbops->owner))
- err = -ENODEV;
+ int err;

- if (!err && info->fbops->fb_open &&
- info->fbops->fb_open(info, 0))
- err = -ENODEV;
+ err = fbcon_open(info);
+ if (err)
+ return err;

if (!err) {
ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
@@ -713,7 +731,7 @@ static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,

if (err) {
con2fb_map[unit] = oldidx;
- module_put(info->fbops->owner);
+ fbcon_release(info);
}

return err;
@@ -724,45 +742,34 @@ static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
int oldidx, int found)
{
struct fbcon_ops *ops = oldinfo->fbcon_par;
- int err = 0, ret;
+ int ret;

- if (oldinfo->fbops->fb_release &&
- oldinfo->fbops->fb_release(oldinfo, 0)) {
- con2fb_map[unit] = oldidx;
- if (!found && newinfo->fbops->fb_release)
- newinfo->fbops->fb_release(newinfo, 0);
- if (!found)
- module_put(newinfo->fbops->owner);
- err = -ENODEV;
- }
+ fbcon_release(oldinfo);

- if (!err) {
- fbcon_del_cursor_work(oldinfo);
- kfree(ops->cursor_state.mask);
- kfree(ops->cursor_data);
- kfree(ops->cursor_src);
- kfree(ops->fontbuffer);
- kfree(oldinfo->fbcon_par);
- oldinfo->fbcon_par = NULL;
- module_put(oldinfo->fbops->owner);
- /*
- If oldinfo and newinfo are driving the same hardware,
- the fb_release() method of oldinfo may attempt to
- restore the hardware state. This will leave the
- newinfo in an undefined state. Thus, a call to
- fb_set_par() may be needed for the newinfo.
- */
- if (newinfo && newinfo->fbops->fb_set_par) {
- ret = newinfo->fbops->fb_set_par(newinfo);
+ fbcon_del_cursor_work(oldinfo);
+ kfree(ops->cursor_state.mask);
+ kfree(ops->cursor_data);
+ kfree(ops->cursor_src);
+ kfree(ops->fontbuffer);
+ kfree(oldinfo->fbcon_par);
+ oldinfo->fbcon_par = NULL;
+ /*
+ If oldinfo and newinfo are driving the same hardware,
+ the fb_release() method of oldinfo may attempt to
+ restore the hardware state. This will leave the
+ newinfo in an undefined state. Thus, a call to
+ fb_set_par() may be needed for the newinfo.
+ */
+ if (newinfo && newinfo->fbops->fb_set_par) {
+ ret = newinfo->fbops->fb_set_par(newinfo);

- if (ret)
- printk(KERN_ERR "con2fb_release_oldinfo: "
- "detected unhandled fb_set_par error, "
- "error code %d\n", ret);
- }
+ if (ret)
+ printk(KERN_ERR "con2fb_release_oldinfo: "
+ "detected unhandled fb_set_par error, "
+ "error code %d\n", ret);
}

- return err;
+ return 0;
}

static void con2fb_init_display(struct vc_data *vc, struct fb_info *info,
@@ -917,7 +924,6 @@ static const char *fbcon_startup(void)
struct fbcon_display *p = &fb_display[fg_console];
struct vc_data *vc = vc_cons[fg_console].d;
const struct font_desc *font = NULL;
- struct module *owner;
struct fb_info *info = NULL;
struct fbcon_ops *ops;
int rows, cols;
@@ -936,17 +942,12 @@ static const char *fbcon_startup(void)
if (!info)
return NULL;

- owner = info->fbops->owner;
- if (!try_module_get(owner))
+ if (fbcon_open(info))
return NULL;
- if (info->fbops->fb_open && info->fbops->fb_open(info, 0)) {
- module_put(owner);
- return NULL;
- }

ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
if (!ops) {
- module_put(owner);
+ fbcon_release(info);
return NULL;
}

@@ -3331,10 +3332,6 @@ static void fbcon_exit(void)
}

if (mapped) {
- if (info->fbops->fb_release)
- info->fbops->fb_release(info, 0);
- module_put(info->fbops->owner);
-
if (info->fbcon_par) {
struct fbcon_ops *ops = info->fbcon_par;

@@ -3344,6 +3341,8 @@ static void fbcon_exit(void)
kfree(info->fbcon_par);
info->fbcon_par = NULL;
}
+
+ fbcon_release(info);
}
}
}
--
2.33.0