# \[PATCH v2 fbdev-for-next 1/2\] fbcon: introduce for\_each\_registered\_fb() helper

- Subsystems: FRAMEBUFFER CONSOLE, FRAMEBUFFER LAYER, FRAMEBUFFER CORE, THE REST
- Maintainers: Helge Deller, Thomas Zimmermann, Simona Vetter, Linus Torvalds
- List: linux-fbdev
- 5 messages, 5 authors
- Page: https://ratatoskr.run/linux-fbdev/2018/06/5320436/t

## \[PATCH v2 fbdev-for-next 1/2\] fbcon: introduce for\_each\_registered\_fb() helper

- From: Yisheng Xie \<hidden\>
- Date: 2018-06-30 07:30:04 
- Message: https://ratatoskr.run/linux-fbdev/2018/06/5320436.md

```text
Following pattern is often used:

 for (i = 0; i < FB_MAX; i++) {
        if (registered_fb[i]) {
                ...
        }
 }

Therefore, as Andy's suggestion, for_each_registered_fb() helper can
be introduced to make the code easier to read and write by reducing
indentation level. It also saves few lines of code in each occurrence.

This patch convert all part here at the same time.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yisheng Xie <redacted>
---
v2:
 - rebase it to fbdev-for-next branch and add one more loop to replace - per Hans
 - Macro should be protected against nested conditionals. - per Andy
 drivers/video/fbdev/core/fbcon.c | 31 +++++++++++--------------------
 drivers/video/fbdev/core/fbmem.c |  4 +---
 include/linux/fb.h               |  4 ++++
 3 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
index 5fb156b..e30d3a1 100644
--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -2234,8 +2234,8 @@ static int fbcon_switch(struct vc_data *vc)
 	 *
 	 * info->currcon = vc->vc_num;
 	 */
-	for (i = 0; i < FB_MAX; i++) {
-		if (registered_fb[i] != NULL && registered_fb[i]->fbcon_par) {
+	for_each_registered_fb(i) {
+		if (registered_fb[i]->fbcon_par) {
 			struct fbcon_ops *o = registered_fb[i]->fbcon_par;
 
 			o->currcon = vc->vc_num;
@@ -3124,11 +3124,9 @@ static int fbcon_fb_unregistered(struct fb_info *info)
 	if (idx = info_idx) {
 		info_idx = -1;
 
-		for (i = 0; i < FB_MAX; i++) {
-			if (registered_fb[i] != NULL) {
-				info_idx = i;
-				break;
-			}
+		for_each_registered_fb(i) {
+			info_idx = i;
+			break;
 		}
 	}
 
@@ -3609,10 +3607,8 @@ static int fbcon_output_notifier(struct notifier_block *nb,
 	deferred_takeover = false;
 	logo_shown = FBCON_LOGO_DONTSHOW;
 
-	for (i = 0; i < FB_MAX; i++) {
-		if (registered_fb[i])
-			fbcon_fb_registered(registered_fb[i]);
-	}
+	for_each_registered_fb(i)
+		fbcon_fb_registered(registered_fb[i]);
 
 	return NOTIFY_OK;
 }
@@ -3638,11 +3634,9 @@ static void fbcon_start(void)
 
 		console_lock();
 
-		for (i = 0; i < FB_MAX; i++) {
-			if (registered_fb[i] != NULL) {
-				info_idx = i;
-				break;
-			}
+		for_each_registered_fb(i) {
+			info_idx = i;
+			break;
 		}
 
 		do_fbcon_takeover(0);
@@ -3669,15 +3663,12 @@ static void fbcon_exit(void)
 	kfree((void *)softback_buf);
 	softback_buf = 0UL;
 
-	for (i = 0; i < FB_MAX; i++) {
+	for_each_registered_fb(i) {
 		int pending = 0;
 
 		mapped = 0;
 		info = registered_fb[i];
 
-		if (info = NULL)
-			continue;
-
 		if (info->queue.func)
 			pending = cancel_work_sync(&info->queue);
 		DPRINTK("fbcon: %s pending work\n", (pending ? "canceled" :
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 609438d..645c6ac 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1593,10 +1593,8 @@ static int do_remove_conflicting_framebuffers(struct apertures_struct *a,
 	int i, ret;
 
 	/* check all firmware fbs and kick off if the base addr overlaps */
-	for (i = 0 ; i < FB_MAX; i++) {
+	for_each_registered_fb(i) {
 		struct apertures_struct *gen_aper;
-		if (!registered_fb[i])
-			continue;
 
 		if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
 			continue;
diff --git a/include/linux/fb.h b/include/linux/fb.h
index aa74a22..fd31e6f 100644
--- a/include/linux/fb.h
+++ b/include/linux/fb.h
@@ -650,6 +650,10 @@ extern int fb_get_color_depth(struct fb_var_screeninfo *var,
 extern int num_registered_fb;
 extern struct class *fb_class;
 
+#define for_each_registered_fb(i)		\
+	for (i = 0; i < FB_MAX; i++)		\
+		if (!registered_fb[i]) {} else
+
 extern int lock_fb_info(struct fb_info *info);
 
 static inline void unlock_fb_info(struct fb_info *info)
-- 
1.9.1

```

## Re: \[PATCH v2 fbdev-for-next 1/2\] fbcon: introduce for\_each\_registered\_fb() helper

- From: Hans de Goede \<hidden\>
- Date: 2018-06-30 10:32:38 
- Message: https://ratatoskr.run/linux-fbdev/2018/06/5320464.md

```text
Hi,

On 30-06-18 09:29, Yisheng Xie wrote:
> Following pattern is often used:
> 
>   for (i = 0; i < FB_MAX; i++) {
>          if (registered_fb[i]) {
>                  ...
>          }
>   }
> 
> Therefore, as Andy's suggestion, for_each_registered_fb() helper can
> be introduced to make the code easier to read and write by reducing
> indentation level. It also saves few lines of code in each occurrence.
> 
> This patch convert all part here at the same time.
> 
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Yisheng Xie <redacted>

Both patches look good to me, and both are:

Acked-by: Hans de Goede <redacted>

Regards,

Hans



> ---
> v2:
>   - rebase it to fbdev-for-next branch and add one more loop to replace - per Hans
>   - Macro should be protected against nested conditionals. - per Andy
>   drivers/video/fbdev/core/fbcon.c | 31 +++++++++++--------------------
>   drivers/video/fbdev/core/fbmem.c |  4 +---
>   include/linux/fb.h               |  4 ++++
>   3 files changed, 16 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index 5fb156b..e30d3a1 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -2234,8 +2234,8 @@ static int fbcon_switch(struct vc_data *vc)
>   	 *
>   	 * info->currcon = vc->vc_num;
>   	 */
> -	for (i = 0; i < FB_MAX; i++) {
> -		if (registered_fb[i] != NULL && registered_fb[i]->fbcon_par) {
> +	for_each_registered_fb(i) {
> +		if (registered_fb[i]->fbcon_par) {
>   			struct fbcon_ops *o = registered_fb[i]->fbcon_par;
>   
>   			o->currcon = vc->vc_num;
> @@ -3124,11 +3124,9 @@ static int fbcon_fb_unregistered(struct fb_info *info)
>   	if (idx = info_idx) {
>   		info_idx = -1;
>   
> -		for (i = 0; i < FB_MAX; i++) {
> -			if (registered_fb[i] != NULL) {
> -				info_idx = i;
> -				break;
> -			}
> +		for_each_registered_fb(i) {
> +			info_idx = i;
> +			break;
>   		}
>   	}
>   
> @@ -3609,10 +3607,8 @@ static int fbcon_output_notifier(struct notifier_block *nb,
>   	deferred_takeover = false;
>   	logo_shown = FBCON_LOGO_DONTSHOW;
>   
> -	for (i = 0; i < FB_MAX; i++) {
> -		if (registered_fb[i])
> -			fbcon_fb_registered(registered_fb[i]);
> -	}
> +	for_each_registered_fb(i)
> +		fbcon_fb_registered(registered_fb[i]);
>   
>   	return NOTIFY_OK;
>   }
> @@ -3638,11 +3634,9 @@ static void fbcon_start(void)
>   
>   		console_lock();
>   
> -		for (i = 0; i < FB_MAX; i++) {
> -			if (registered_fb[i] != NULL) {
> -				info_idx = i;
> -				break;
> -			}
> +		for_each_registered_fb(i) {
> +			info_idx = i;
> +			break;
>   		}
>   
>   		do_fbcon_takeover(0);
> @@ -3669,15 +3663,12 @@ static void fbcon_exit(void)
>   	kfree((void *)softback_buf);
>   	softback_buf = 0UL;
>   
> -	for (i = 0; i < FB_MAX; i++) {
> +	for_each_registered_fb(i) {
>   		int pending = 0;
>   
>   		mapped = 0;
>   		info = registered_fb[i];
>   
> -		if (info = NULL)
> -			continue;
> -
>   		if (info->queue.func)
>   			pending = cancel_work_sync(&info->queue);
>   		DPRINTK("fbcon: %s pending work\n", (pending ? "canceled" :
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index 609438d..645c6ac 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1593,10 +1593,8 @@ static int do_remove_conflicting_framebuffers(struct apertures_struct *a,
>   	int i, ret;
>   
>   	/* check all firmware fbs and kick off if the base addr overlaps */
> -	for (i = 0 ; i < FB_MAX; i++) {
> +	for_each_registered_fb(i) {
>   		struct apertures_struct *gen_aper;
> -		if (!registered_fb[i])
> -			continue;
>   
>   		if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
>   			continue;
> diff --git a/include/linux/fb.h b/include/linux/fb.h
> index aa74a22..fd31e6f 100644
> --- a/include/linux/fb.h
> +++ b/include/linux/fb.h
> @@ -650,6 +650,10 @@ extern int fb_get_color_depth(struct fb_var_screeninfo *var,
>   extern int num_registered_fb;
>   extern struct class *fb_class;
>   
> +#define for_each_registered_fb(i)		\
> +	for (i = 0; i < FB_MAX; i++)		\
> +		if (!registered_fb[i]) {} else
> +
>   extern int lock_fb_info(struct fb_info *info);
>   
>   static inline void unlock_fb_info(struct fb_info *info)
> 
```

## Re: \[PATCH v2 fbdev-for-next 1/2\] fbcon: introduce for\_each\_registered\_fb() helper

- From: Andy Shevchenko \<andriy.shevchenko@linux.intel.com\>
- Date: 2018-06-30 15:50:29 
- Message: https://ratatoskr.run/linux-fbdev/2018/06/5320531.md

```text
On Sat, 2018-06-30 at 15:29 +0800, Yisheng Xie wrote:
> Following pattern is often used:
> 
>  for (i = 0; i < FB_MAX; i++) {
>         if (registered_fb[i]) {
>                 ...
>         }
>  }
> 
> Therefore, as Andy's suggestion, for_each_registered_fb() helper can
> be introduced to make the code easier to read and write by reducing
> indentation level. It also saves few lines of code in each occurrence.
> 
> This patch convert all part here at the same time.
> 

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Yisheng Xie <redacted>
> ---
> v2:
>  - rebase it to fbdev-for-next branch and add one more loop to replace
> - per Hans
>  - Macro should be protected against nested conditionals. - per Andy
>  drivers/video/fbdev/core/fbcon.c | 31 +++++++++++--------------------
>  drivers/video/fbdev/core/fbmem.c |  4 +---
>  include/linux/fb.h               |  4 ++++
>  3 files changed, 16 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/video/fbdev/core/fbcon.c
> b/drivers/video/fbdev/core/fbcon.c
> index 5fb156b..e30d3a1 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -2234,8 +2234,8 @@ static int fbcon_switch(struct vc_data *vc)
>  	 *
>  	 * info->currcon = vc->vc_num;
>  	 */
> -	for (i = 0; i < FB_MAX; i++) {
> -		if (registered_fb[i] != NULL && registered_fb[i]-
> >fbcon_par) {
> +	for_each_registered_fb(i) {
> +		if (registered_fb[i]->fbcon_par) {
>  			struct fbcon_ops *o = registered_fb[i]-
> >fbcon_par;
>  
>  			o->currcon = vc->vc_num;
> @@ -3124,11 +3124,9 @@ static int fbcon_fb_unregistered(struct fb_info
> *info)
>  	if (idx = info_idx) {
>  		info_idx = -1;
>  
> -		for (i = 0; i < FB_MAX; i++) {
> -			if (registered_fb[i] != NULL) {
> -				info_idx = i;
> -				break;
> -			}
> +		for_each_registered_fb(i) {
> +			info_idx = i;
> +			break;
>  		}
>  	}
>  
> @@ -3609,10 +3607,8 @@ static int fbcon_output_notifier(struct
> notifier_block *nb,
>  	deferred_takeover = false;
>  	logo_shown = FBCON_LOGO_DONTSHOW;
>  
> -	for (i = 0; i < FB_MAX; i++) {
> -		if (registered_fb[i])
> -			fbcon_fb_registered(registered_fb[i]);
> -	}
> +	for_each_registered_fb(i)
> +		fbcon_fb_registered(registered_fb[i]);
>  
>  	return NOTIFY_OK;
>  }
> @@ -3638,11 +3634,9 @@ static void fbcon_start(void)
>  
>  		console_lock();
>  
> -		for (i = 0; i < FB_MAX; i++) {
> -			if (registered_fb[i] != NULL) {
> -				info_idx = i;
> -				break;
> -			}
> +		for_each_registered_fb(i) {
> +			info_idx = i;
> +			break;
>  		}
>  
>  		do_fbcon_takeover(0);
> @@ -3669,15 +3663,12 @@ static void fbcon_exit(void)
>  	kfree((void *)softback_buf);
>  	softback_buf = 0UL;
>  
> -	for (i = 0; i < FB_MAX; i++) {
> +	for_each_registered_fb(i) {
>  		int pending = 0;
>  
>  		mapped = 0;
>  		info = registered_fb[i];
>  
> -		if (info = NULL)
> -			continue;
> -
>  		if (info->queue.func)
>  			pending = cancel_work_sync(&info->queue);
>  		DPRINTK("fbcon: %s pending work\n", (pending ?
> "canceled" :
> diff --git a/drivers/video/fbdev/core/fbmem.c
> b/drivers/video/fbdev/core/fbmem.c
> index 609438d..645c6ac 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1593,10 +1593,8 @@ static int
> do_remove_conflicting_framebuffers(struct apertures_struct *a,
>  	int i, ret;
>  
>  	/* check all firmware fbs and kick off if the base addr
> overlaps */
> -	for (i = 0 ; i < FB_MAX; i++) {
> +	for_each_registered_fb(i) {
>  		struct apertures_struct *gen_aper;
> -		if (!registered_fb[i])
> -			continue;
>  
>  		if (!(registered_fb[i]->flags &
> FBINFO_MISC_FIRMWARE))
>  			continue;
> diff --git a/include/linux/fb.h b/include/linux/fb.h
> index aa74a22..fd31e6f 100644
> --- a/include/linux/fb.h
> +++ b/include/linux/fb.h
> @@ -650,6 +650,10 @@ extern int fb_get_color_depth(struct
> fb_var_screeninfo *var,
>  extern int num_registered_fb;
>  extern struct class *fb_class;
>  
> +#define for_each_registered_fb(i)		\
> +	for (i = 0; i < FB_MAX; i++)		\
> +		if (!registered_fb[i]) {} else
> +
>  extern int lock_fb_info(struct fb_info *info);
>  
>  static inline void unlock_fb_info(struct fb_info *info)

-- 
Andy Shevchenko [ref]
Intel Finland Oy
```

## Re: \[PATCH v2 fbdev-for-next 1/2\] fbcon: introduce for\_each\_registered\_fb() helper

- From: Jani Nikula \<jani.nikula@linux.intel.com\>
- Date: 2018-07-02 13:58:12 
- Message: https://ratatoskr.run/linux-fbdev/2018/07/5322034.md

```text
On Sat, 30 Jun 2018, Yisheng Xie [ref] wrote:
> Following pattern is often used:
>
>  for (i = 0; i < FB_MAX; i++) {
>         if (registered_fb[i]) {
>                 ...
>         }
>  }
>
> Therefore, as Andy's suggestion, for_each_registered_fb() helper can
> be introduced to make the code easier to read and write by reducing
> indentation level. It also saves few lines of code in each occurrence.
>
> This patch convert all part here at the same time.
>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Yisheng Xie <redacted>
> ---
> v2:
>  - rebase it to fbdev-for-next branch and add one more loop to replace - per Hans
>  - Macro should be protected against nested conditionals. - per Andy
>  drivers/video/fbdev/core/fbcon.c | 31 +++++++++++--------------------
>  drivers/video/fbdev/core/fbmem.c |  4 +---
>  include/linux/fb.h               |  4 ++++
>  3 files changed, 16 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/video/fbdev/core/fbcon.c b/drivers/video/fbdev/core/fbcon.c
> index 5fb156b..e30d3a1 100644
> --- a/drivers/video/fbdev/core/fbcon.c
> +++ b/drivers/video/fbdev/core/fbcon.c
> @@ -2234,8 +2234,8 @@ static int fbcon_switch(struct vc_data *vc)
>  	 *
>  	 * info->currcon = vc->vc_num;
>  	 */
> -	for (i = 0; i < FB_MAX; i++) {
> -		if (registered_fb[i] != NULL && registered_fb[i]->fbcon_par) {
> +	for_each_registered_fb(i) {
> +		if (registered_fb[i]->fbcon_par) {
>  			struct fbcon_ops *o = registered_fb[i]->fbcon_par;
>  
>  			o->currcon = vc->vc_num;
> @@ -3124,11 +3124,9 @@ static int fbcon_fb_unregistered(struct fb_info *info)
>  	if (idx = info_idx) {
>  		info_idx = -1;
>  
> -		for (i = 0; i < FB_MAX; i++) {
> -			if (registered_fb[i] != NULL) {
> -				info_idx = i;
> -				break;
> -			}
> +		for_each_registered_fb(i) {
> +			info_idx = i;
> +			break;
>  		}
>  	}
>  
> @@ -3609,10 +3607,8 @@ static int fbcon_output_notifier(struct notifier_block *nb,
>  	deferred_takeover = false;
>  	logo_shown = FBCON_LOGO_DONTSHOW;
>  
> -	for (i = 0; i < FB_MAX; i++) {
> -		if (registered_fb[i])
> -			fbcon_fb_registered(registered_fb[i]);
> -	}
> +	for_each_registered_fb(i)
> +		fbcon_fb_registered(registered_fb[i]);
>  
>  	return NOTIFY_OK;
>  }
> @@ -3638,11 +3634,9 @@ static void fbcon_start(void)
>  
>  		console_lock();
>  
> -		for (i = 0; i < FB_MAX; i++) {
> -			if (registered_fb[i] != NULL) {
> -				info_idx = i;
> -				break;
> -			}
> +		for_each_registered_fb(i) {
> +			info_idx = i;
> +			break;
>  		}
>  
>  		do_fbcon_takeover(0);
> @@ -3669,15 +3663,12 @@ static void fbcon_exit(void)
>  	kfree((void *)softback_buf);
>  	softback_buf = 0UL;
>  
> -	for (i = 0; i < FB_MAX; i++) {
> +	for_each_registered_fb(i) {
>  		int pending = 0;
>  
>  		mapped = 0;
>  		info = registered_fb[i];
>  
> -		if (info = NULL)
> -			continue;
> -
>  		if (info->queue.func)
>  			pending = cancel_work_sync(&info->queue);
>  		DPRINTK("fbcon: %s pending work\n", (pending ? "canceled" :
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index 609438d..645c6ac 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -1593,10 +1593,8 @@ static int do_remove_conflicting_framebuffers(struct apertures_struct *a,
>  	int i, ret;
>  
>  	/* check all firmware fbs and kick off if the base addr overlaps */
> -	for (i = 0 ; i < FB_MAX; i++) {
> +	for_each_registered_fb(i) {
>  		struct apertures_struct *gen_aper;
> -		if (!registered_fb[i])
> -			continue;
>  
>  		if (!(registered_fb[i]->flags & FBINFO_MISC_FIRMWARE))
>  			continue;
> diff --git a/include/linux/fb.h b/include/linux/fb.h
> index aa74a22..fd31e6f 100644
> --- a/include/linux/fb.h
> +++ b/include/linux/fb.h
> @@ -650,6 +650,10 @@ extern int fb_get_color_depth(struct fb_var_screeninfo *var,
>  extern int num_registered_fb;
>  extern struct class *fb_class;
>  
> +#define for_each_registered_fb(i)		\
> +	for (i = 0; i < FB_MAX; i++)		\
> +		if (!registered_fb[i]) {} else

There's for_each_if in drmP.h to handle dangling else. Maybe that should
be lifted outside of drm.

BR,
Jani.

> +
>  extern int lock_fb_info(struct fb_info *info);
>  
>  static inline void unlock_fb_info(struct fb_info *info)

-- 
Jani Nikula, Intel Open Source Graphics Center
```

## Re: \[PATCH v2 fbdev-for-next 1/2\] fbcon: introduce for\_each\_registered\_fb() helper

- From: Bartlomiej Zolnierkiewicz \<hidden\>
- Date: 2018-07-24 15:18:35 
- Message: https://ratatoskr.run/linux-fbdev/2018/07/5341246.md

```text
On Saturday, June 30, 2018 03:29:49 PM Yisheng Xie wrote:
> Following pattern is often used:
> 
>  for (i = 0; i < FB_MAX; i++) {
>         if (registered_fb[i]) {
>                 ...
>         }
>  }
> 
> Therefore, as Andy's suggestion, for_each_registered_fb() helper can
> be introduced to make the code easier to read and write by reducing
> indentation level. It also saves few lines of code in each occurrence.
> 
> This patch convert all part here at the same time.
> 
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Yisheng Xie <redacted>

Patch queued for 4.19, thanks.

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

```