Re: [PATCH v2 06/19] fbcon: Use delayed work for cursor

Thomas Zimmermann
2022-02-10T11:38:10Z

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Am 08.02.22 um 22:08 schrieb Daniel Vetter:
> Allows us to delete a bunch of hand-rolled stuff. Also to simplify the
> code we initialize the cursor_work completely when we allocate the
> fbcon_ops structure, instead of trying to cope with console
> re-initialization.
>
> The motiviation here is that fbcon code stops using the fb_info.queue,
> which helps with locking issues around cleanup and all that in a later
> patch.
>
> Also note that this allows us to ditch the hand-rolled work cleanup in
> fbcon_exit - we already call fbcon_del_cursor_timer, which takes care
> of everything. Plus this was racy anyway.
>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
> Cc: Daniel Vetter <daniel@ffwll.ch>
> Cc: Claudio Suarez <cssk@net-c.es>
> Cc: Du Cheng <ducheng2@gmail.com>
> Cc: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
> drivers/video/fbdev/core/fbcon.c | 85 +++++++++++++-------------------
> drivers/video/fbdev/core/fbcon.h | 4 +-
> 2 files changed, 35 insertions(+), 54 deletions(-)
>
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index 83f0223f5333..a368ed602e2e 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -350,8 +350,8 @@ static int get_color(struct vc_data *vc, struct fb_info *info,
>
> static void fb_flashcursor(struct work_struct *work)
> {
> - struct fb_info *info = container_of(work, struct fb_info, queue);
> - struct fbcon_ops *ops = info->fbcon_par;
> + struct fbcon_ops *ops = container_of(work, struct fbcon_ops, cursor_work.work);
> + struct fb_info *info;
> struct vc_data *vc = NULL;
> int c;
> int mode;
> @@ -364,7 +364,10 @@ static void fb_flashcursor(struct work_struct *work)
> if (ret == 0)
> return;
>
> - if (ops && ops->currcon != -1)
> + /* protected by console_lock */
> + info = ops->info;
> +
> + if (ops->currcon != -1)
> vc = vc_cons[ops->currcon].d;
>
> if (!vc || !con_is_visible(vc) ||
> @@ -380,42 +383,25 @@ static void fb_flashcursor(struct work_struct *work)
> ops->cursor(vc, info, mode, get_color(vc, info, c, 1),
> get_color(vc, info, c, 0));
> console_unlock();
> -}
>
> -static void cursor_timer_handler(struct timer_list *t)
> -{
> - struct fbcon_ops *ops = from_timer(ops, t, cursor_timer);
> - struct fb_info *info = ops->info;
> -
> - queue_work(system_power_efficient_wq, &info->queue);
> - mod_timer(&ops->cursor_timer, jiffies + ops->cur_blink_jiffies);
> + queue_delayed_work(system_power_efficient_wq, &ops->cursor_work,
> + ops->cur_blink_jiffies);
> }
>
> -static void fbcon_add_cursor_timer(struct fb_info *info)
> +static void fbcon_add_cursor_work(struct fb_info *info)
> {
> struct fbcon_ops *ops = info->fbcon_par;
>
> - if ((!info->queue.func || info->queue.func == fb_flashcursor) &&
> - !(ops->flags & FBCON_FLAGS_CURSOR_TIMER) &&
> - !fbcon_cursor_noblink) {
> - if (!info->queue.func)
> - INIT_WORK(&info->queue, fb_flashcursor);
> -
> - timer_setup(&ops->cursor_timer, cursor_timer_handler, 0);
> - mod_timer(&ops->cursor_timer, jiffies + ops->cur_blink_jiffies);
> - ops->flags |= FBCON_FLAGS_CURSOR_TIMER;
> - }
> + if (!fbcon_cursor_noblink)
> + queue_delayed_work(system_power_efficient_wq, &ops->cursor_work,
> + ops->cur_blink_jiffies);
> }
>
> -static void fbcon_del_cursor_timer(struct fb_info *info)
> +static void fbcon_del_cursor_work(struct fb_info *info)
> {
> struct fbcon_ops *ops = info->fbcon_par;
>
> - if (info->queue.func == fb_flashcursor &&
> - ops->flags & FBCON_FLAGS_CURSOR_TIMER) {
> - del_timer_sync(&ops->cursor_timer);
> - ops->flags &= ~FBCON_FLAGS_CURSOR_TIMER;
> - }
> + cancel_delayed_work_sync(&ops->cursor_work);
> }
>
> #ifndef MODULE
> @@ -714,6 +700,8 @@ static int con2fb_acquire_newinfo(struct vc_data *vc, struct fb_info *info,
> ops = kzalloc(sizeof(struct fbcon_ops), GFP_KERNEL);
> if (!ops)
> err = -ENOMEM;
> +
> + INIT_DELAYED_WORK(&ops->cursor_work, fb_flashcursor);

There's similar code in fbcon_startup() when there should be a single
init function for fbcon_ops. Maybe something for later.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>

> }
>
> if (!err) {
> @@ -751,7 +739,7 @@ static int con2fb_release_oldinfo(struct vc_data *vc, struct fb_info *oldinfo,
> }
>
> if (!err) {
> - fbcon_del_cursor_timer(oldinfo);
> + fbcon_del_cursor_work(oldinfo);
> kfree(ops->cursor_state.mask);
> kfree(ops->cursor_data);
> kfree(ops->cursor_src);
> @@ -867,7 +855,7 @@ static int set_con2fb_map(int unit, int newidx, int user)
> logo_shown != FBCON_LOGO_DONTSHOW);
>
> if (!found)
> - fbcon_add_cursor_timer(info);
> + fbcon_add_cursor_work(info);
> con2fb_map_boot[unit] = newidx;
> con2fb_init_display(vc, info, unit, show_logo);
> }
> @@ -964,6 +952,8 @@ static const char *fbcon_startup(void)
> return NULL;
> }
>
> + INIT_DELAYED_WORK(&ops->cursor_work, fb_flashcursor);
> +
> ops->currcon = -1;
> ops->graphics = 1;
> ops->cur_rotate = -1;
> @@ -1006,7 +996,7 @@ static const char *fbcon_startup(void)
> info->var.yres,
> info->var.bits_per_pixel);
>
> - fbcon_add_cursor_timer(info);
> + fbcon_add_cursor_work(info);
> return display_desc;
> }
>
> @@ -1194,7 +1184,7 @@ static void fbcon_deinit(struct vc_data *vc)
> goto finished;
>
> if (con_is_visible(vc))
> - fbcon_del_cursor_timer(info);
> + fbcon_del_cursor_work(info);
>
> ops->flags &= ~FBCON_FLAGS_INIT;
> finished:
> @@ -1320,9 +1310,9 @@ static void fbcon_cursor(struct vc_data *vc, int mode)
> return;
>
> if (vc->vc_cursor_type & CUR_SW)
> - fbcon_del_cursor_timer(info);
> + fbcon_del_cursor_work(info);
> else
> - fbcon_add_cursor_timer(info);
> + fbcon_add_cursor_work(info);
>
> ops->cursor_flash = (mode == CM_ERASE) ? 0 : 1;
>
> @@ -2132,14 +2122,14 @@ static int fbcon_switch(struct vc_data *vc)
> }
>
> if (old_info != info)
> - fbcon_del_cursor_timer(old_info);
> + fbcon_del_cursor_work(old_info);
> }
>
> if (fbcon_is_inactive(vc, info) ||
> ops->blank_state != FB_BLANK_UNBLANK)
> - fbcon_del_cursor_timer(info);
> + fbcon_del_cursor_work(info);
> else
> - fbcon_add_cursor_timer(info);
> + fbcon_add_cursor_work(info);
>
> set_blitting_type(vc, info);
> ops->cursor_reset = 1;
> @@ -2247,9 +2237,9 @@ static int fbcon_blank(struct vc_data *vc, int blank, int mode_switch)
>
> if (mode_switch || fbcon_is_inactive(vc, info) ||
> ops->blank_state != FB_BLANK_UNBLANK)
> - fbcon_del_cursor_timer(info);
> + fbcon_del_cursor_work(info);
> else
> - fbcon_add_cursor_timer(info);
> + fbcon_add_cursor_work(info);
>
> return 0;
> }
> @@ -3181,7 +3171,7 @@ static ssize_t show_cursor_blink(struct device *device,
> if (!ops)
> goto err;
>
> - blink = (ops->flags & FBCON_FLAGS_CURSOR_TIMER) ? 1 : 0;
> + blink = delayed_work_pending(&ops->cursor_work);
> err:
> console_unlock();
> return snprintf(buf, PAGE_SIZE, "%d\n", blink);
> @@ -3210,10 +3200,10 @@ static ssize_t store_cursor_blink(struct device *device,
>
> if (blink) {
> fbcon_cursor_noblink = 0;
> - fbcon_add_cursor_timer(info);
> + fbcon_add_cursor_work(info);
> } else {
> fbcon_cursor_noblink = 1;
> - fbcon_del_cursor_timer(info);
> + fbcon_del_cursor_work(info);
> }
>
> err:
> @@ -3314,15 +3304,9 @@ static void fbcon_exit(void)
> #endif
>
> for_each_registered_fb(i) {
> - int pending = 0;
> -
> mapped = 0;
> info = registered_fb[i];
>
> - if (info->queue.func)
> - pending = cancel_work_sync(&info->queue);
> - pr_debug("fbcon: %s pending work\n", (pending ? "canceled" : "no"));
> -
> for (j = first_fb_vc; j <= last_fb_vc; j++) {
> if (con2fb_map[j] == i) {
> mapped = 1;
> @@ -3338,15 +3322,12 @@ static void fbcon_exit(void)
> if (info->fbcon_par) {
> struct fbcon_ops *ops = info->fbcon_par;
>
> - fbcon_del_cursor_timer(info);
> + fbcon_del_cursor_work(info);
> kfree(ops->cursor_src);
> kfree(ops->cursor_state.mask);
> kfree(info->fbcon_par);
> info->fbcon_par = NULL;
> }
> -
> - if (info->queue.func == fb_flashcursor)
> - info->queue.func = NULL;
> }
> }
> }
> diff --git a/drivers/video/fbdev/core/fbcon.h b/drivers/video/fbdev/core/fbcon.h
> index 969d41ecede5..6708ca0048aa 100644
> --- a/drivers/video/fbdev/core/fbcon.h
> +++ b/drivers/video/fbdev/core/fbcon.h
> @@ -14,11 +14,11 @@
> #include <linux/types.h>
> #include <linux/vt_buffer.h>
> #include <linux/vt_kern.h>
> +#include <linux/workqueue.h>
>
> #include <asm/io.h>
>
> #define FBCON_FLAGS_INIT 1
> -#define FBCON_FLAGS_CURSOR_TIMER 2
>
> /*
> * This is the interface between the low-level console driver and the
> @@ -68,7 +68,7 @@ struct fbcon_ops {
> int (*update_start)(struct fb_info *info);
> int (*rotate_font)(struct fb_info *info, struct vc_data *vc);
> struct fb_var_screeninfo var; /* copy of the current fb_var_screeninfo */
> - struct timer_list cursor_timer; /* Cursor timer */
> + struct delayed_work cursor_work; /* Cursor timer */
> struct fb_cursor cursor_state;
> struct fbcon_display *p;
> struct fb_info *info;

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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