Thomas Zimmermann <tzimmermann@xxxxxxx> writes: > Detect registered instances of fb_info by reading the reference > counter from struct fb_info.read. Avoids looking at the dev field > and prepares fbdev for making struct fb_info.dev optional. > > Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> > Cc: Steve Glendinning <steve.glendinning@xxxxxxxxxxx> > --- > drivers/video/fbdev/smscufx.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/fbdev/smscufx.c b/drivers/video/fbdev/smscufx.c > index 17cec62cc65d..adb2b1fe8383 100644 > --- a/drivers/video/fbdev/smscufx.c > +++ b/drivers/video/fbdev/smscufx.c > @@ -1496,7 +1496,7 @@ static int ufx_setup_modes(struct ufx_data *dev, struct fb_info *info, > u8 *edid; > int i, result = 0, tries = 3; > > - if (info->dev) /* only use mutex if info has been registered */ > + if (refcount_read(&info->count)) /* only use mutex if info has been registered */ The struct fb_info .count refcount is protected by the registration_lock mutex in register_framebuffer(). I think this operation isn't thread safe ? But that was also the case for info->dev check, so I guess is OK and this change is for an old fbdev driver anyways. Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> -- Best regards, Javier Martinez Canillas Core Platforms Red Hat
