From 8813e86f6d82a7931446c3cbc5d596f77d0f1ba6 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Mon, 27 Nov 2023 14:16:01 +0100 Subject: [PATCH] fbdev: Remove default file-I/O implementations Drop the default implementations for file read, write and mmap operations. Each fbdev driver must now provide an implementation and select any necessary helpers. If no implementation has been set, fbdev returns an errno code to user space. The code is the same as if the operation had not been set in the file_operations struct. This change makes the fbdev helpers for I/O memory optional. Most systems only use system-memory framebuffers via DRM's fbdev emulation. v2: * warn once if I/O callbacks are missing (Javier) Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Link: https://patchwork.freedesktop.org/patch/msgid/20231127131655.4020-33-tzimmermann@suse.de --- drivers/video/fbdev/core/Kconfig | 1 - drivers/video/fbdev/core/fb_chrdev.c | 37 +++++++++------------------- include/linux/fb.h | 5 ++++ 3 files changed, 17 insertions(+), 26 deletions(-) diff --git a/drivers/video/fbdev/core/Kconfig b/drivers/video/fbdev/core/Kconfig index faab5d50cac3..21053bf00dc5 100644 --- a/drivers/video/fbdev/core/Kconfig +++ b/drivers/video/fbdev/core/Kconfig @@ -4,7 +4,6 @@ # config FB_CORE - select FB_IOMEM_FOPS select VIDEO_CMDLINE tristate diff --git a/drivers/video/fbdev/core/fb_chrdev.c b/drivers/video/fbdev/core/fb_chrdev.c index 089441c9d810..4ebd16b7e3b8 100644 --- a/drivers/video/fbdev/core/fb_chrdev.c +++ b/drivers/video/fbdev/core/fb_chrdev.c @@ -34,13 +34,13 @@ static ssize_t fb_read(struct file *file, char __user *buf, size_t count, loff_t if (!info) return -ENODEV; + if (fb_WARN_ON_ONCE(info, !info->fbops->fb_read)) + return -EINVAL; + if (info->state != FBINFO_STATE_RUNNING) return -EPERM; - if (info->fbops->fb_read) - return info->fbops->fb_read(info, buf, count, ppos); - - return fb_io_read(info, buf, count, ppos); + return info->fbops->fb_read(info, buf, count, ppos); } static ssize_t fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) @@ -50,13 +50,13 @@ static ssize_t fb_write(struct file *file, const char __user *buf, size_t count, if (!info) return -ENODEV; + if (fb_WARN_ON_ONCE(info, !info->fbops->fb_write)) + return -EINVAL; + if (info->state != FBINFO_STATE_RUNNING) return -EPERM; - if (info->fbops->fb_write) - return info->fbops->fb_write(info, buf, count, ppos); - - return fb_io_write(info, buf, count, ppos); + return info->fbops->fb_write(info, buf, count, ppos); } static long do_fb_ioctl(struct fb_info *info, unsigned int cmd, @@ -319,24 +319,11 @@ static int fb_mmap(struct file *file, struct vm_area_struct *vma) if (!info) return -ENODEV; - mutex_lock(&info->mm_lock); - - if (info->fbops->fb_mmap) { - - res = info->fbops->fb_mmap(info, vma); -#if IS_ENABLED(CONFIG_FB_DEFERRED_IO) - } else if (info->fbdefio) { - /* - * FB deferred I/O wants you to handle mmap in your drivers. At a - * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap(). - */ - dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n"); - res = -ENODEV; -#endif - } else { - res = fb_io_mmap(info, vma); - } + if (fb_WARN_ON_ONCE(info, !info->fbops->fb_mmap)) + return -ENODEV; + mutex_lock(&info->mm_lock); + res = info->fbops->fb_mmap(info, vma); mutex_unlock(&info->mm_lock); return res; diff --git a/include/linux/fb.h b/include/linux/fb.h index 24f0ec366235..05dc9624897d 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -867,4 +867,9 @@ static inline bool fb_modesetting_disabled(const char *drvname) #define fb_warn_once(fb_info, fmt, ...) \ pr_warn_once("fb%d: " fmt, (fb_info)->node, ##__VA_ARGS__) +#define fb_WARN_ONCE(fb_info, condition, fmt, ...) \ + WARN_ONCE(condition, "fb%d: " fmt, (fb_info)->node, ##__VA_ARGS__) +#define fb_WARN_ON_ONCE(fb_info, x) \ + fb_WARN_ONCE(fb_info, (x), "%s", "fb_WARN_ON_ONCE(" __stringify(x) ")") + #endif /* _LINUX_FB_H */ -- 2.25.1