From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Clark Subject: [PATCH] drm: refcnt drm_framebuffer Date: Tue, 31 Jul 2012 11:20:21 -0500 Message-ID: <1343751621-1868-1-git-send-email-rob.clark@linaro.org> Return-path: Received: from mail-ob0-f174.google.com ([209.85.214.174]:43129 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754744Ab2GaQUh (ORCPT ); Tue, 31 Jul 2012 12:20:37 -0400 Received: by obbuo13 with SMTP id uo13so10809073obb.19 for ; Tue, 31 Jul 2012 09:20:36 -0700 (PDT) Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org Cc: patches@linaro.org, Greg KH , Tomi Valkeinen , Andy Gross , Rob Clark From: Rob Clark This simplifies drm fb lifetime, and if the crtc/plane needs to hold a ref to the fb when disabling a pipe until the next vblank, this avoids the need to make disabling an overlay synchronous. This is a problem that shows up when userspace is using a drm plane to implement a hw cursor.. making overlay disable synchronous causes a performance problem when x11 is rapidly enabling/disabling the hw cursor. But not making it synchronous opens up a race condition for crashing if userspace turns around and immediately deletes the fb. Refcnt'ing the fb makes it possible to solve this problem. Signed-off-by: Rob Clark --- drivers/gpu/drm/drm_crtc.c | 38 ++++++++++++++++++++++++++--- drivers/gpu/drm/exynos/exynos_drm_fbdev.c | 4 +-- drivers/gpu/drm/i915/intel_display.c | 4 +-- include/drm/drm_crtc.h | 4 +++ 4 files changed, 43 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c index 08a7aa7..2f928a3 100644 --- a/drivers/gpu/drm/drm_crtc.c +++ b/drivers/gpu/drm/drm_crtc.c @@ -294,6 +294,8 @@ int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb, { int ret; + kref_init(&fb->refcount); + ret = drm_mode_object_get(dev, &fb->base, DRM_MODE_OBJECT_FB); if (ret) return ret; @@ -307,6 +309,36 @@ int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb, } EXPORT_SYMBOL(drm_framebuffer_init); +static void drm_framebuffer_free(struct kref *kref) +{ + struct drm_framebuffer *fb = + container_of(kref, struct drm_framebuffer, refcount); + fb->funcs->destroy(fb); +} + +/** + * drm_framebuffer_unreference - unref a framebuffer + * + * LOCKING: + * Caller must hold mode config lock. + */ +void drm_framebuffer_unreference(struct drm_framebuffer *fb) +{ + struct drm_device *dev = fb->dev; + WARN_ON(!mutex_is_locked(&dev->mode_config.mutex)); + kref_put(&fb->refcount, drm_framebuffer_free); +} +EXPORT_SYMBOL(drm_framebuffer_unreference); + +/** + * drm_framebuffer_reference - incr the fb refcnt + */ +void drm_framebuffer_reference(struct drm_framebuffer *fb) +{ + kref_get(&fb->refcount); +} +EXPORT_SYMBOL(drm_framebuffer_reference); + /** * drm_framebuffer_cleanup - remove a framebuffer object * @fb: framebuffer to remove @@ -1031,7 +1063,7 @@ void drm_mode_config_cleanup(struct drm_device *dev) } list_for_each_entry_safe(fb, fbt, &dev->mode_config.fb_list, head) { - fb->funcs->destroy(fb); + drm_framebuffer_unreference(fb); } list_for_each_entry_safe(crtc, ct, &dev->mode_config.crtc_list, head) { @@ -2339,7 +2371,7 @@ int drm_mode_rmfb(struct drm_device *dev, /* TODO unhock the destructor from the buffer object */ list_del(&fb->filp_head); - fb->funcs->destroy(fb); + drm_framebuffer_unreference(fb); out: mutex_unlock(&dev->mode_config.mutex); @@ -2490,7 +2522,7 @@ void drm_fb_release(struct drm_file *priv) mutex_lock(&dev->mode_config.mutex); list_for_each_entry_safe(fb, tfb, &priv->fbs, filp_head) { list_del(&fb->filp_head); - fb->funcs->destroy(fb); + drm_framebuffer_unreference(fb); } mutex_unlock(&dev->mode_config.mutex); } diff --git a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c index d5586cc..05695d6 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_fbdev.c +++ b/drivers/gpu/drm/exynos/exynos_drm_fbdev.c @@ -266,8 +266,8 @@ static void exynos_drm_fbdev_destroy(struct drm_device *dev, /* release drm framebuffer and real buffer */ if (fb_helper->fb && fb_helper->fb->funcs) { fb = fb_helper->fb; - if (fb && fb->funcs->destroy) - fb->funcs->destroy(fb); + if (fb) + drm_framebuffer_unreference(fb); } /* release linux framebuffer */ diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index a8538ac..a9d2328 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -5467,7 +5467,7 @@ bool intel_get_load_detect_pipe(struct intel_encoder *intel_encoder, if (!drm_crtc_helper_set_mode(crtc, mode, 0, 0, old_fb)) { DRM_DEBUG_KMS("failed to set mode on load-detect pipe\n"); if (old->release_fb) - old->release_fb->funcs->destroy(old->release_fb); + drm_framebuffer_unreference(old->release_fb); crtc->fb = old_fb; return false; } @@ -5497,7 +5497,7 @@ void intel_release_load_detect_pipe(struct intel_encoder *intel_encoder, drm_helper_disable_unused_functions(dev); if (old->release_fb) - old->release_fb->funcs->destroy(old->release_fb); + drm_framebuffer_unreference(old->release_fb); return; } diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h index bac55c2..8a5b16d 100644 --- a/include/drm/drm_crtc.h +++ b/include/drm/drm_crtc.h @@ -221,6 +221,7 @@ struct drm_display_info { }; struct drm_framebuffer_funcs { + /* note: use drm_framebuffer_unreference() */ void (*destroy)(struct drm_framebuffer *framebuffer); int (*create_handle)(struct drm_framebuffer *fb, struct drm_file *file_priv, @@ -245,6 +246,7 @@ struct drm_framebuffer_funcs { struct drm_framebuffer { struct drm_device *dev; + struct kref refcount; struct list_head head; struct drm_mode_object base; const struct drm_framebuffer_funcs *funcs; @@ -923,6 +925,8 @@ extern void drm_framebuffer_set_object(struct drm_device *dev, extern int drm_framebuffer_init(struct drm_device *dev, struct drm_framebuffer *fb, const struct drm_framebuffer_funcs *funcs); +void drm_framebuffer_unreference(struct drm_framebuffer *fb); +void drm_framebuffer_reference(struct drm_framebuffer *fb); extern void drm_framebuffer_cleanup(struct drm_framebuffer *fb); extern int drmfb_probe(struct drm_device *dev, struct drm_crtc *crtc); extern int drmfb_remove(struct drm_device *dev, struct drm_framebuffer *fb); -- 1.7.9.5