Re: [PATCH 27/30] fbdev/core: Move procfs code to separate file

Sam Ravnborg
2023-06-07T20:33:41Z

Hi Thomas,

On Mon, Jun 05, 2023 at 04:48:09PM +0200, Thomas Zimmermann wrote:
> Move fbdev's procfs code into a separate file and contain it in
> init and cleanup helpers. No functional changes.
Maybe add:
Delete the unused for_each_registered_fb while touching the code.

The change to use proc_remove is not really documented.
But code looks ok.

I am not fan that we have introduced a few globals again.
But it looks like the way to go for now.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
With an improved changelog:
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
> ---
> drivers/video/fbdev/core/Makefile | 1 +
> drivers/video/fbdev/core/fb_internal.h | 12 ++++-
> drivers/video/fbdev/core/fb_procfs.c | 62 ++++++++++++++++++++++++++
> drivers/video/fbdev/core/fbmem.c | 51 +++------------------
> 4 files changed, 80 insertions(+), 46 deletions(-)
> create mode 100644 drivers/video/fbdev/core/fb_procfs.c
>
> diff --git a/drivers/video/fbdev/core/Makefile b/drivers/video/fbdev/core/Makefile
> index eee3295bc225..665320160f70 100644
> --- a/drivers/video/fbdev/core/Makefile
> +++ b/drivers/video/fbdev/core/Makefile
> @@ -3,6 +3,7 @@ obj-$(CONFIG_FB_NOTIFY) += fb_notify.o
> obj-$(CONFIG_FB) += fb.o
> fb-y := fb_backlight.o \
> fb_info.o \
> + fb_procfs.o \
> fbmem.o fbmon.o fbcmap.o fbsysfs.o \
> modedb.o fbcvt.o fb_cmdline.o fb_io_fops.o
> fb-$(CONFIG_FB_DEFERRED_IO) += fb_defio.o
> diff --git a/drivers/video/fbdev/core/fb_internal.h b/drivers/video/fbdev/core/fb_internal.h
> index 0b9640ae7a3d..51f7c9f04e45 100644
> --- a/drivers/video/fbdev/core/fb_internal.h
> +++ b/drivers/video/fbdev/core/fb_internal.h
> @@ -3,7 +3,17 @@
> #ifndef _FB_INTERNAL_H
> #define _FB_INTERNAL_H
>
> -struct fb_info;
> +#include <linux/fb.h>
> +#include <linux/mutex.h>
> +
> +/* fbmem.c */
> +extern struct mutex registration_lock;
> +extern struct fb_info *registered_fb[FB_MAX];
> +extern int num_registered_fb;
> +
> +/* fb_procfs.c */
> +int fb_init_procfs(void);
> +void fb_cleanup_procfs(void);
>
> /* fbsysfs.c */
> int fb_device_create(struct fb_info *fb_info);
> diff --git a/drivers/video/fbdev/core/fb_procfs.c b/drivers/video/fbdev/core/fb_procfs.c
> new file mode 100644
> index 000000000000..59641142f8aa
> --- /dev/null
> +++ b/drivers/video/fbdev/core/fb_procfs.c
> @@ -0,0 +1,62 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <linux/proc_fs.h>
> +
> +#include "fb_internal.h"
> +
> +static struct proc_dir_entry *fb_proc_dir_entry;
> +
> +static void *fb_seq_start(struct seq_file *m, loff_t *pos)
> +{
> + mutex_lock(&registration_lock);
> +
> + return (*pos < FB_MAX) ? pos : NULL;
> +}
> +
> +static void fb_seq_stop(struct seq_file *m, void *v)
> +{
> + mutex_unlock(&registration_lock);
> +}
> +
> +static void *fb_seq_next(struct seq_file *m, void *v, loff_t *pos)
> +{
> + (*pos)++;
> +
> + return (*pos < FB_MAX) ? pos : NULL;
> +}
> +
> +static int fb_seq_show(struct seq_file *m, void *v)
> +{
> + int i = *(loff_t *)v;
> + struct fb_info *fi = registered_fb[i];
> +
> + if (fi)
> + seq_printf(m, "%d %s\n", fi->node, fi->fix.id);
> +
> + return 0;
> +}
> +
> +static const struct seq_operations __maybe_unused fb_proc_seq_ops = {
> + .start = fb_seq_start,
> + .stop = fb_seq_stop,
> + .next = fb_seq_next,
> + .show = fb_seq_show,
> +};
> +
> +int fb_init_procfs(void)
> +{
> + struct proc_dir_entry *proc;
> +
> + proc = proc_create_seq("fb", 0, NULL, &fb_proc_seq_ops);
> + if (!proc)
> + return -ENOMEM;
> +
> + fb_proc_dir_entry = proc;
> +
> + return 0;
> +}
> +
> +void fb_cleanup_procfs(void)
> +{
> + proc_remove(fb_proc_dir_entry);
> +}
> diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
> index 66532774d351..de1e45240161 100644
> --- a/drivers/video/fbdev/core/fbmem.c
> +++ b/drivers/video/fbdev/core/fbmem.c
> @@ -24,9 +24,7 @@
> #include <linux/vt.h>
> #include <linux/init.h>
> #include <linux/linux_logo.h>
> -#include <linux/proc_fs.h>
> #include <linux/platform_device.h>
> -#include <linux/seq_file.h>
> #include <linux/console.h>
> #include <linux/kmod.h>
> #include <linux/err.h>
> @@ -48,13 +46,9 @@
>
> #define FBPIXMAPSIZE (1024 * 8)
>
> -static DEFINE_MUTEX(registration_lock);
> -
> +DEFINE_MUTEX(registration_lock);
> struct fb_info *registered_fb[FB_MAX] __read_mostly;
> int num_registered_fb __read_mostly;
> -#define for_each_registered_fb(i) \
> - for (i = 0; i < FB_MAX; i++) \
> - if (!registered_fb[i]) {} else
>
> bool fb_center_logo __read_mostly;
>
> @@ -705,40 +699,6 @@ int fb_show_logo(struct fb_info *info, int rotate) { return 0; }
> EXPORT_SYMBOL(fb_prepare_logo);
> EXPORT_SYMBOL(fb_show_logo);
>
> -static void *fb_seq_start(struct seq_file *m, loff_t *pos)
> -{
> - mutex_lock(&registration_lock);
> - return (*pos < FB_MAX) ? pos : NULL;
> -}
> -
> -static void *fb_seq_next(struct seq_file *m, void *v, loff_t *pos)
> -{
> - (*pos)++;
> - return (*pos < FB_MAX) ? pos : NULL;
> -}
> -
> -static void fb_seq_stop(struct seq_file *m, void *v)
> -{
> - mutex_unlock(&registration_lock);
> -}
> -
> -static int fb_seq_show(struct seq_file *m, void *v)
> -{
> - int i = *(loff_t *)v;
> - struct fb_info *fi = registered_fb[i];
> -
> - if (fi)
> - seq_printf(m, "%d %s\n", fi->node, fi->fix.id);
> - return 0;
> -}
> -
> -static const struct seq_operations __maybe_unused proc_fb_seq_ops = {
> - .start = fb_seq_start,
> - .next = fb_seq_next,
> - .stop = fb_seq_stop,
> - .show = fb_seq_show,
> -};
> -
> /*
> * We hold a reference to the fb_info in file->private_data,
> * but if the current registered fb has changed, we don't
> @@ -1624,8 +1584,9 @@ fbmem_init(void)
> {
> int ret;
>
> - if (!proc_create_seq("fb", 0, NULL, &proc_fb_seq_ops))
> - return -ENOMEM;
> + ret = fb_init_procfs();
> + if (ret)
> + return ret;
>
> ret = register_chrdev(FB_MAJOR, "fb", &fb_fops);
> if (ret) {
> @@ -1648,7 +1609,7 @@ fbmem_init(void)
> err_class:
> unregister_chrdev(FB_MAJOR, "fb");
> err_chrdev:
> - remove_proc_entry("fb", NULL);
> + fb_cleanup_procfs();
> return ret;
> }
>
> @@ -1659,7 +1620,7 @@ fbmem_exit(void)
> {
> fb_console_exit();
>
> - remove_proc_entry("fb", NULL);
> + fb_cleanup_procfs();
> class_destroy(fb_class);
> unregister_chrdev(FB_MAJOR, "fb");
> }
> --
> 2.40.1