Modifying fb_ops directly to override fb_mmap with fb_deferred_io_mmap and then resetting it to NULL afterwards causes problems all over the place. First, it prevents making the fbops member of struct fb_info a const pointer, which means we can't make struct fb_ops const anywhere. Second, a few places have to go out of their way to restore the original fb_mmap pointer that gets reset to NULL.
Preserve the passed in fb_ops by making a copy of it and modifying that instead. Add a deferred_io_private member to struct fb_info to store the pointer to the old fb_ops, and restore that at cleanup. Cc: Jaya Kumar <[email protected]> Cc: [email protected] Signed-off-by: Jani Nikula <[email protected]> --- Note: If the approach is acceptable, we'll also need to handle the error returns on memory allocation failures at fb_deferred_io_init() call sites. There are 13. --- drivers/video/fbdev/core/fb_defio.c | 25 ++++++++++++++++++++++--- include/linux/fb.h | 3 ++- 2 files changed, 24 insertions(+), 4 deletions(-) diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c index 82c20c6047b0..36697844c1e0 100644 --- a/drivers/video/fbdev/core/fb_defio.c +++ b/drivers/video/fbdev/core/fb_defio.c @@ -200,13 +200,23 @@ static void fb_deferred_io_work(struct work_struct *work) mutex_unlock(&fbdefio->lock); } -void fb_deferred_io_init(struct fb_info *info) +int fb_deferred_io_init(struct fb_info *info) { struct fb_deferred_io *fbdefio = info->fbdefio; + struct fb_ops *fbops; BUG_ON(!fbdefio); + + fbops = kmemdup(info->fbops, sizeof(*fbops), GFP_KERNEL); + if (!fbops) + return -ENOMEM; + + fbops->fb_mmap = fb_deferred_io_mmap; + info->deferred_io_private = info->fbops; + info->fbops = fbops; + mutex_init(&fbdefio->lock); - info->fbops->fb_mmap = fb_deferred_io_mmap; + INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work); INIT_LIST_HEAD(&fbdefio->pagelist); if (fbdefio->delay == 0) /* set a default of 1 s */ @@ -229,6 +239,12 @@ void fb_deferred_io_cleanup(struct fb_info *info) int i; BUG_ON(!fbdefio); + + /* sanity check against misuse */ + if (WARN_ON(!info->deferred_io_private || + info->fbops->fb_mmap != fb_deferred_io_mmap)) + return; + cancel_delayed_work_sync(&info->deferred_work); /* clear out the mapping that we setup */ @@ -237,7 +253,10 @@ void fb_deferred_io_cleanup(struct fb_info *info) page->mapping = NULL; } - info->fbops->fb_mmap = NULL; + kfree(info->fbops); + info->fbops = info->deferred_io_private; + info->deferred_io_private = NULL; + mutex_destroy(&fbdefio->lock); } EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup); diff --git a/include/linux/fb.h b/include/linux/fb.h index a6ad528990de..65f2abd47745 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -470,6 +470,7 @@ struct fb_info { #ifdef CONFIG_FB_DEFERRED_IO struct delayed_work deferred_work; struct fb_deferred_io *fbdefio; + void *deferred_io_private; #endif struct fb_ops *fbops; @@ -658,7 +659,7 @@ static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch, /* drivers/video/fb_defio.c */ int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma); -extern void fb_deferred_io_init(struct fb_info *info); +extern int fb_deferred_io_init(struct fb_info *info); extern void fb_deferred_io_open(struct fb_info *info, struct inode *inode, struct file *file); -- 2.20.1 _______________________________________________ dri-devel mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/dri-devel
