When a user-space process writes directly to the fbdev framebuffer, we hit a circular locking dependency. Fix this by introducing a local delayed work callback so that the defio lock can be released before calling into the modesetting code for a dirty update.
Signed-off-by: Thomas Hellstrom thellstrom@vmware.com Reviewed-by: Sinclair Yeh syeh@vmware.com --- drivers/gpu/drm/vmwgfx/vmwgfx_fb.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c index 042c5b4..3b1faf7 100644 --- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c +++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c @@ -68,8 +68,7 @@ struct vmw_fb_par {
struct drm_crtc *crtc; struct drm_connector *con; - - bool local_mode; + struct delayed_work local_work; };
static int vmw_fb_setcolreg(unsigned regno, unsigned red, unsigned green, @@ -167,8 +166,10 @@ static int vmw_fb_blank(int blank, struct fb_info *info) * Dirty code */
-static void vmw_fb_dirty_flush(struct vmw_fb_par *par) +static void vmw_fb_dirty_flush(struct work_struct *work) { + struct vmw_fb_par *par = container_of(work, struct vmw_fb_par, + local_work.work); struct vmw_private *vmw_priv = par->vmw_priv; struct fb_info *info = vmw_priv->fb_info; unsigned long irq_flags; @@ -248,7 +249,6 @@ static void vmw_fb_dirty_mark(struct vmw_fb_par *par, unsigned x1, unsigned y1, unsigned width, unsigned height) { - struct fb_info *info = par->vmw_priv->fb_info; unsigned long flags; unsigned x2 = x1 + width; unsigned y2 = y1 + height; @@ -262,7 +262,8 @@ static void vmw_fb_dirty_mark(struct vmw_fb_par *par, /* if we are active start the dirty work * we share the work with the defio system */ if (par->dirty.active) - schedule_delayed_work(&info->deferred_work, VMW_DIRTY_DELAY); + schedule_delayed_work(&par->local_work, + VMW_DIRTY_DELAY); } else { if (x1 < par->dirty.x1) par->dirty.x1 = x1; @@ -326,9 +327,14 @@ static void vmw_deferred_io(struct fb_info *info, par->dirty.x2 = info->var.xres; par->dirty.y2 = y2; spin_unlock_irqrestore(&par->dirty.lock, flags); - }
- vmw_fb_dirty_flush(par); + /* + * Since we've already waited on this work once, try to + * execute asap. + */ + cancel_delayed_work(&par->local_work); + schedule_delayed_work(&par->local_work, 0); + } };
static struct fb_deferred_io vmw_defio = { @@ -601,11 +607,7 @@ static int vmw_fb_set_par(struct fb_info *info) /* If there already was stuff dirty we wont * schedule a new work, so lets do it now */
-#if (defined(VMWGFX_STANDALONE) && defined(VMWGFX_FB_DEFERRED)) - schedule_delayed_work(&par->def_par.deferred_work, 0); -#else - schedule_delayed_work(&info->deferred_work, 0); -#endif + schedule_delayed_work(&par->local_work, 0);
out_unlock: if (old_mode) @@ -662,6 +664,7 @@ int vmw_fb_init(struct vmw_private *vmw_priv) vmw_priv->fb_info = info; par = info->par; memset(par, 0, sizeof(*par)); + INIT_DELAYED_WORK(&par->local_work, &vmw_fb_dirty_flush); par->vmw_priv = vmw_priv; par->vmalloc = NULL; par->max_width = fb_width; @@ -784,6 +787,7 @@ int vmw_fb_close(struct vmw_private *vmw_priv)
/* ??? order */ fb_deferred_io_cleanup(info); + cancel_delayed_work_sync(&par->local_work); unregister_framebuffer(info);
(void) vmw_fb_kms_detach(par, true, true); @@ -811,6 +815,7 @@ int vmw_fb_off(struct vmw_private *vmw_priv) spin_unlock_irqrestore(&par->dirty.lock, flags);
flush_delayed_work(&info->deferred_work); + flush_delayed_work(&par->local_work);
mutex_lock(&par->bo_mutex); (void) vmw_fb_kms_detach(par, true, false);