Introduce a device-managed variant of register_framebuffer() which automatically unregisters the framebuffer on device destruction. This can simplify the error handling and resource management in drivers. Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx> --- This is a fixed resend of [0], which was broken. Thanks to Bert [1], and Chaitanya Kumar [2] for reporting the issue. [0] https://lore.kernel.org/lkml/20240827-efifb-sysfs-v1-3-c9cc3e052180@xxxxxxxxxxxxxx/ [1] https://lore.kernel.org/lkml/20240829224124.2978-1-spasswolf@xxxxxx/ [2] https://lore.kernel.org/lkml/SJ1PR11MB612925C1C533C09F8F62F7CBB9972@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Helge, I didn't document the function devm_unregister_framebuffer() as it is only an internal helper and will ever only used by one user, similar to other helpers in fbmem.c. --- drivers/video/fbdev/core/fbmem.c | 30 ++++++++++++++++++++++++++++++ include/linux/fb.h | 1 + 2 files changed, 31 insertions(+) diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 4c4ad0a86a50..3c568cff2913 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -544,6 +544,36 @@ unregister_framebuffer(struct fb_info *fb_info) } EXPORT_SYMBOL(unregister_framebuffer); +static void devm_unregister_framebuffer(void *data) +{ + struct fb_info *info = data; + + unregister_framebuffer(info); +} + +/** + * devm_register_framebuffer - resource-managed frame buffer device registration + * @dev: device the framebuffer belongs to + * @fb_info: frame buffer info structure + * + * Registers a frame buffer device @fb_info to device @dev. + * + * Returns negative errno on error, or zero for success. + * + */ +int +devm_register_framebuffer(struct device *dev, struct fb_info *fb_info) +{ + int ret; + + ret = register_framebuffer(fb_info); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, devm_unregister_framebuffer, fb_info); +} +EXPORT_SYMBOL(devm_register_framebuffer); + /** * fb_set_suspend - low level driver signals suspend * @info: framebuffer affected diff --git a/include/linux/fb.h b/include/linux/fb.h index db7d97b10964..abf6643ebcaf 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -601,6 +601,7 @@ extern ssize_t fb_sys_write(struct fb_info *info, const char __user *buf, /* fbmem.c */ extern int register_framebuffer(struct fb_info *fb_info); extern void unregister_framebuffer(struct fb_info *fb_info); +extern int devm_register_framebuffer(struct device *dev, struct fb_info *fb_info); extern char* fb_get_buffer_offset(struct fb_info *info, struct fb_pixmap *buf, u32 size); extern void fb_pad_unaligned_buffer(u8 *dst, u32 d_pitch, u8 *src, u32 idx, u32 height, u32 shift_high, u32 shift_low, u32 mod); --- base-commit: 20371ba120635d9ab7fc7670497105af8f33eb08 change-id: 20240830-fbdev-devm_register_framebuffer-647e9c103b9a Best regards, -- Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
