From: Rob Clark Date: Fri, 16 Dec 2011 17:34:34 +0000 (-0600) Subject: staging: drm/omap: avoid aquiring mutex in atomic context (v2) X-Git-Tag: firefly_0821_release~3680^2~3804^2~40 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=af69592aa098ff8cd640e8109ba946db3c1cdb4e;p=firefly-linux-kernel-4.4.55.git staging: drm/omap: avoid aquiring mutex in atomic context (v2) omap_gem_roll() could be called by fbcon in atomic context or when struct_mutext is held. Avoid aquiring mutex (deadlock), or calling tiler_pin() (which itself is not safe for atomic context) in these cases. Signed-off-by: Rob Clark Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/staging/omapdrm/omap_gem.c b/drivers/staging/omapdrm/omap_gem.c index 96848913085f..63490f75350a 100644 --- a/drivers/staging/omapdrm/omap_gem.c +++ b/drivers/staging/omapdrm/omap_gem.c @@ -538,10 +538,22 @@ int omap_gem_roll(struct drm_gem_object *obj, uint32_t roll) return -EINVAL; } - mutex_lock(&obj->dev->struct_mutex); - omap_obj->roll = roll; + if (in_atomic() || mutex_is_locked(&obj->dev->struct_mutex)) { + /* this can get called from fbcon in atomic context.. so + * just ignore it and wait for next time called from + * interruptible context to update the PAT.. the result + * may be that user sees wrap-around instead of scrolling + * momentarily on the screen. If we wanted to be fancier + * we could perhaps schedule some workqueue work at this + * point. + */ + return 0; + } + + mutex_lock(&obj->dev->struct_mutex); + /* if we aren't mapped yet, we don't need to do anything */ if (omap_obj->block) { struct page **pages;