On Fri, Nov 29, 2019 at 12:29:31PM +0200, Jani Nikula wrote:
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.
Since the only user of the fbops->fb_mmap hook is fb_mmap() in fbmem.c, call fb_deferred_io_mmap() directly when deferred IO is enabled, and avoid modifying fb_ops altogether.
Simply use info->fbdefio to determine whether deferred IO should be used or not. This should be accurate enough for all use cases, although perhaps not pedantically correct.
v2: Simplify considerably by calling fb_deferred_io_mmap() directly (Daniel, Ville)
Cc: Jaya Kumar jayalk@intworks.biz Cc: linux-fbdev@vger.kernel.org Cc: Daniel Vetter daniel@ffwll.ch Cc: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Jani Nikula jani.nikula@intel.com
drivers/video/fbdev/core/fb_defio.c | 3 --- drivers/video/fbdev/core/fbmem.c | 15 +++++++++++---- 2 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c index 82c20c6047b0..a591d291b231 100644 --- a/drivers/video/fbdev/core/fb_defio.c +++ b/drivers/video/fbdev/core/fb_defio.c @@ -171,7 +171,6 @@ int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) vma->vm_private_data = info; return 0; } -EXPORT_SYMBOL(fb_deferred_io_mmap);
/* workqueue callback */ static void fb_deferred_io_work(struct work_struct *work) @@ -206,7 +205,6 @@ void fb_deferred_io_init(struct fb_info *info)
BUG_ON(!fbdefio); 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 */
@@ -237,7 +235,6 @@ void fb_deferred_io_cleanup(struct fb_info *info) page->mapping = NULL; }
- info->fbops->fb_mmap = NULL; mutex_destroy(&fbdefio->lock);
} EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup); diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 86b06a599f96..990550930a8e 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -1332,16 +1332,23 @@ static int fb_mmap(struct file *file, struct vm_area_struct * vma) { struct fb_info *info = file_fb_info(file);
- struct fb_ops *fb;
- int (*fb_mmap_fn)(struct fb_info *info, struct vm_area_struct *vma);
Oh I function pointer for tidier control flow, neato.
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch
unsigned long mmio_pgoff; unsigned long start; u32 len;
if (!info) return -ENODEV;
- fb = info->fbops; mutex_lock(&info->mm_lock);
- if (fb->fb_mmap) {
- fb_mmap_fn = info->fbops->fb_mmap;
+#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
- if (info->fbdefio)
fb_mmap_fn = fb_deferred_io_mmap;+#endif
if (fb_mmap_fn) { int res;
/*
@@ -1349,7 +1356,7 @@ fb_mmap(struct file *file, struct vm_area_struct * vma) * SME protection is removed ahead of the call */ vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
res = fb->fb_mmap(info, vma);
res = fb_mmap_fn(info, vma);-- 2.20.1