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From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: [PATCH 20/35] drm: create drm_framebuffer_lookup
Date: Thu, 10 Jan 2013 21:48:01 +0100	[thread overview]
Message-ID: <1357850897-27102-21-git-send-email-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <1357850897-27102-1-git-send-email-daniel.vetter@ffwll.ch>

And replace all fb lookups with it. Also add a WARN to
drm_mode_object_find since that is now no longer the blessed interface
to look up an fb. And add kerneldoc to both functions.

This only updates all callsites, but immediately drops the acquired
refence again. Hence all callers still rely on the fact that a mode fb
can't disappear while they're holding the struct mutex. Subsequent
patches will instate proper use of refcounts, and then rework the rmfb
and unref code to no longer serialize fb destruction with the
mode_config lock. We don't want that since otherwise a compositor
might end up stalling for a few frames in rmfb.

v2: Don't use kref_get_unless_zero - Greg KH doesn't like that kind of
interface.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/drm_crtc.c            |  109 ++++++++++++++++++++++-----------
 drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c |   24 ++++----
 include/drm/drm_crtc.h                |    2 +
 3 files changed, 86 insertions(+), 49 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index d387ddb..1c13984 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -294,11 +294,24 @@ static void drm_mode_object_put(struct drm_device *dev,
 	mutex_unlock(&dev->mode_config.idr_mutex);
 }
 
+/**
+ * drm_mode_object_find - look up a drm object with static lifetime
+ * @dev: drm device
+ * @id: id of the mode object
+ * @type: type of the mode object
+ *
+ * Note that framebuffers cannot be looked up with this functions - since those
+ * are reference counted, they need special treatment.
+ */
 struct drm_mode_object *drm_mode_object_find(struct drm_device *dev,
 		uint32_t id, uint32_t type)
 {
 	struct drm_mode_object *obj = NULL;
 
+	/* Framebuffers are reference counted and need their own lookup
+	 * function.*/
+	WARN_ON(type == DRM_MODE_OBJECT_FB);
+
 	mutex_lock(&dev->mode_config.idr_mutex);
 	obj = idr_find(&dev->mode_config.crtc_idr, id);
 	if (!obj || (obj->type != type) || (obj->id != id))
@@ -359,6 +372,40 @@ static void drm_framebuffer_free(struct kref *kref)
 }
 
 /**
+ * drm_framebuffer_lookup - look up a drm framebuffer and grab a reference
+ * @dev: drm device
+ * @id: id of the fb object
+ *
+ * If successful, this grabs an additional reference to the framebuffer -
+ * callers need to make sure to eventually unreference the returned framebuffer
+ * again.
+ */
+struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
+					       uint32_t id)
+{
+	struct drm_mode_object *obj = NULL;
+	struct drm_framebuffer *fb;
+
+	mutex_lock(&dev->mode_config.fb_lock);
+
+	mutex_lock(&dev->mode_config.idr_mutex);
+	obj = idr_find(&dev->mode_config.crtc_idr, id);
+	if (!obj || (obj->type != DRM_MODE_OBJECT_FB) || (obj->id != id))
+		fb = NULL;
+	else
+		fb = obj_to_fb(obj);
+	mutex_unlock(&dev->mode_config.idr_mutex);
+
+	if (fb)
+		kref_get(&fb->refcount);
+
+	mutex_unlock(&dev->mode_config.fb_lock);
+
+	return fb;
+}
+EXPORT_SYMBOL(drm_framebuffer_lookup);
+
+/**
  * drm_framebuffer_unreference - unref a framebuffer
  * @fb: framebuffer to unref
  *
@@ -1788,17 +1835,15 @@ int drm_mode_setplane(struct drm_device *dev, void *data,
 	}
 	crtc = obj_to_crtc(obj);
 
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, plane_req->fb_id,
-				   DRM_MODE_OBJECT_FB);
-	mutex_unlock(&dev->mode_config.fb_lock);
-	if (!obj) {
+	fb = drm_framebuffer_lookup(dev, plane_req->fb_id);
+	if (!fb) {
 		DRM_DEBUG_KMS("Unknown framebuffer ID %d\n",
 			      plane_req->fb_id);
 		ret = -ENOENT;
 		goto out;
 	}
-	fb = obj_to_fb(obj);
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
 
 	/* Check whether this plane supports the fb pixel format. */
 	for (i = 0; i < plane->format_count; i++)
@@ -1933,17 +1978,16 @@ int drm_mode_setcrtc(struct drm_device *dev, void *data,
 			}
 			fb = crtc->fb;
 		} else {
-			mutex_lock(&dev->mode_config.fb_lock);
-			obj = drm_mode_object_find(dev, crtc_req->fb_id,
-						   DRM_MODE_OBJECT_FB);
-			mutex_unlock(&dev->mode_config.fb_lock);
-			if (!obj) {
+			fb = drm_framebuffer_lookup(dev, crtc_req->fb_id);
+			if (!fb) {
 				DRM_DEBUG_KMS("Unknown FB ID%d\n",
 						crtc_req->fb_id);
 				ret = -EINVAL;
 				goto out;
 			}
-			fb = obj_to_fb(obj);
+			/* fb is protect by the mode_config lock, so drop the
+			 * ref immediately */
+			drm_framebuffer_unreference(fb);
 		}
 
 		mode = drm_mode_create(dev);
@@ -2392,7 +2436,6 @@ int drm_mode_addfb2(struct drm_device *dev,
 int drm_mode_rmfb(struct drm_device *dev,
 		   void *data, struct drm_file *file_priv)
 {
-	struct drm_mode_object *obj;
 	struct drm_framebuffer *fb = NULL;
 	struct drm_framebuffer *fbl = NULL;
 	uint32_t *id = data;
@@ -2403,16 +2446,13 @@ int drm_mode_rmfb(struct drm_device *dev,
 		return -EINVAL;
 
 	drm_modeset_lock_all(dev);
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, *id, DRM_MODE_OBJECT_FB);
-	/* TODO check that we really get a framebuffer back. */
-	if (!obj) {
-		mutex_unlock(&dev->mode_config.fb_lock);
+	fb = drm_framebuffer_lookup(dev, *id);
+	if (!fb) {
 		ret = -EINVAL;
 		goto out;
 	}
-	fb = obj_to_fb(obj);
-	mutex_unlock(&dev->mode_config.fb_lock);
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
 
 	mutex_lock(&file_priv->fbs_lock);
 	list_for_each_entry(fbl, &file_priv->fbs, filp_head)
@@ -2451,7 +2491,6 @@ int drm_mode_getfb(struct drm_device *dev,
 		   void *data, struct drm_file *file_priv)
 {
 	struct drm_mode_fb_cmd *r = data;
-	struct drm_mode_object *obj;
 	struct drm_framebuffer *fb;
 	int ret = 0;
 
@@ -2459,14 +2498,13 @@ int drm_mode_getfb(struct drm_device *dev,
 		return -EINVAL;
 
 	drm_modeset_lock_all(dev);
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, r->fb_id, DRM_MODE_OBJECT_FB);
-	mutex_unlock(&dev->mode_config.fb_lock);
-	if (!obj) {
+	fb = drm_framebuffer_lookup(dev, r->fb_id);
+	if (!fb) {
 		ret = -EINVAL;
 		goto out;
 	}
-	fb = obj_to_fb(obj);
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
 
 	r->height = fb->height;
 	r->width = fb->width;
@@ -2489,7 +2527,6 @@ int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
 	struct drm_clip_rect __user *clips_ptr;
 	struct drm_clip_rect *clips = NULL;
 	struct drm_mode_fb_dirty_cmd *r = data;
-	struct drm_mode_object *obj;
 	struct drm_framebuffer *fb;
 	unsigned flags;
 	int num_clips;
@@ -2499,14 +2536,13 @@ int drm_mode_dirtyfb_ioctl(struct drm_device *dev,
 		return -EINVAL;
 
 	drm_modeset_lock_all(dev);
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, r->fb_id, DRM_MODE_OBJECT_FB);
-	mutex_unlock(&dev->mode_config.fb_lock);
-	if (!obj) {
+	fb = drm_framebuffer_lookup(dev, r->fb_id);
+	if (!fb) {
 		ret = -EINVAL;
 		goto out_err1;
 	}
-	fb = obj_to_fb(obj);
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
 
 	num_clips = r->num_clips;
 	clips_ptr = (struct drm_clip_rect __user *)(unsigned long)r->clips_ptr;
@@ -3586,12 +3622,11 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
 	if (crtc->funcs->page_flip == NULL)
 		goto out;
 
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, page_flip->fb_id, DRM_MODE_OBJECT_FB);
-	mutex_unlock(&dev->mode_config.fb_lock);
-	if (!obj)
+	fb = drm_framebuffer_lookup(dev, page_flip->fb_id);
+	if (!fb)
 		goto out;
-	fb = obj_to_fb(obj);
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
 
 	hdisplay = crtc->mode.hdisplay;
 	vdisplay = crtc->mode.vdisplay;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c
index 0d6a161..1b8f428 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ioctl.c
@@ -131,7 +131,7 @@ int vmw_present_ioctl(struct drm_device *dev, void *data,
 	struct vmw_master *vmaster = vmw_master(file_priv->master);
 	struct drm_vmw_rect __user *clips_ptr;
 	struct drm_vmw_rect *clips = NULL;
-	struct drm_mode_object *obj;
+	struct drm_framebuffer *fb;
 	struct vmw_framebuffer *vfb;
 	struct vmw_resource *res;
 	uint32_t num_clips;
@@ -165,15 +165,15 @@ int vmw_present_ioctl(struct drm_device *dev, void *data,
 
 	drm_modeset_lock_all(dev);
 
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, arg->fb_id, DRM_MODE_OBJECT_FB);
-	mutex_unlock(&dev->mode_config.fb_lock);
-	if (!obj) {
+	fb = drm_framebuffer_lookup(dev, arg->fb_id);
+	if (!fb) {
 		DRM_ERROR("Invalid framebuffer id.\n");
 		ret = -EINVAL;
 		goto out_no_fb;
 	}
-	vfb = vmw_framebuffer_to_vfb(obj_to_fb(obj));
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
+	vfb = vmw_framebuffer_to_vfb(fb);
 
 	ret = ttm_read_lock(&vmaster->lock, true);
 	if (unlikely(ret != 0))
@@ -217,7 +217,7 @@ int vmw_present_readback_ioctl(struct drm_device *dev, void *data,
 	struct vmw_master *vmaster = vmw_master(file_priv->master);
 	struct drm_vmw_rect __user *clips_ptr;
 	struct drm_vmw_rect *clips = NULL;
-	struct drm_mode_object *obj;
+	struct drm_framebuffer *fb;
 	struct vmw_framebuffer *vfb;
 	uint32_t num_clips;
 	int ret;
@@ -250,16 +250,16 @@ int vmw_present_readback_ioctl(struct drm_device *dev, void *data,
 
 	drm_modeset_lock_all(dev);
 
-	mutex_lock(&dev->mode_config.fb_lock);
-	obj = drm_mode_object_find(dev, arg->fb_id, DRM_MODE_OBJECT_FB);
-	mutex_unlock(&dev->mode_config.fb_lock);
-	if (!obj) {
+	fb = drm_framebuffer_lookup(dev, arg->fb_id);
+	if (!fb) {
 		DRM_ERROR("Invalid framebuffer id.\n");
 		ret = -EINVAL;
 		goto out_no_fb;
 	}
+	/* fb is protect by the mode_config lock, so drop the ref immediately */
+	drm_framebuffer_unreference(fb);
 
-	vfb = vmw_framebuffer_to_vfb(obj_to_fb(obj));
+	vfb = vmw_framebuffer_to_vfb(fb);
 	if (!vfb->dmabuf) {
 		DRM_ERROR("Framebuffer not dmabuf backed.\n");
 		ret = -EINVAL;
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index c35a807..7dc1b31 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -958,6 +958,8 @@ 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);
+extern struct drm_framebuffer *drm_framebuffer_lookup(struct drm_device *dev,
+						      uint32_t id);
 extern void drm_framebuffer_unreference(struct drm_framebuffer *fb);
 extern void drm_framebuffer_reference(struct drm_framebuffer *fb);
 extern void drm_framebuffer_remove(struct drm_framebuffer *fb);
-- 
1.7.10.4

  parent reply	other threads:[~2013-01-10 20:48 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-01-10 20:47 [PATCH 00/36] kms locking rework Daniel Vetter
2013-01-10 20:47 ` [PATCH 01/35] drm: review locking rules in drm_crtc.c Daniel Vetter
2013-01-10 20:47 ` [PATCH 02/35] drm/doc: integrate drm_crtc.c kerneldoc Daniel Vetter
2013-01-10 20:47 ` [PATCH 03/35] drm/<drivers>: reorder framebuffer init sequence Daniel Vetter
2013-01-11 21:06   ` Rob Clark
2013-01-10 20:47 ` [PATCH 04/35] drm/vmwgfx: " Daniel Vetter
2013-01-10 20:47 ` [PATCH 05/35] drm/gma500: move fbcon restore to lastclose Daniel Vetter
2013-01-10 20:47 ` [PATCH 06/35] drm/nouveau: protect evo_wait/evo_kick sections with a channel mutex Daniel Vetter
2013-01-10 20:47 ` [PATCH 07/35] drm/nouveau: try to protect nbo->pin_refcount Daniel Vetter
2013-01-10 20:47 ` [PATCH 08/35] drm/<drivers>: Unified handling of unimplemented fb->create_handle Daniel Vetter
2013-01-18 15:00   ` Thierry Reding
2013-01-18 18:32     ` Daniel Vetter
2013-01-10 20:47 ` [PATCH 09/35] drm: encapsulate crtc->set_config calls Daniel Vetter
2013-01-10 20:47 ` [PATCH 10/35] drm: add drm_modeset_lock|unlock_all Daniel Vetter
2013-01-10 20:47 ` [PATCH 11/35] drm/i915: use drm_modeset_lock_all Daniel Vetter
2013-01-10 20:47 ` [PATCH 12/35] drm/gma500: " Daniel Vetter
2013-01-10 22:36   ` Alan Cox
2013-01-11 13:25     ` Daniel Vetter
2013-01-10 20:47 ` [PATCH 13/35] drm/ast: " Daniel Vetter
2013-01-10 20:47 ` [PATCH 14/35] drm/shmobile: " Daniel Vetter
2013-01-10 20:47 ` [PATCH 15/35] drm/vmgfx: " Daniel Vetter
2013-01-10 20:47 ` [PATCH 16/35] drm: add per-crtc locks Daniel Vetter
2013-01-10 20:47 ` [PATCH 17/35] drm: only take the crtc lock for ->cursor_set Daniel Vetter
2013-01-10 20:47 ` [PATCH 18/35] drm: only take the crtc lock for ->cursor_move Daniel Vetter
2013-01-10 20:48 ` [PATCH 19/35] drm: revamp locking around fb creation/destruction Daniel Vetter
2013-01-10 20:48 ` Daniel Vetter [this message]
2013-01-10 20:48 ` [PATCH 21/35] drm: revamp framebuffer cleanup interfaces Daniel Vetter
2013-01-10 20:48 ` [PATCH 22/35] drm: reference framebuffers which are on the idr Daniel Vetter
2013-01-10 20:48 ` [PATCH 23/35] drm: nest modeset locks within fpriv->fbs_lock Daniel Vetter
2013-01-10 20:48 ` [PATCH 24/35] drm: push modeset_lock_all into ->fb_create driver callbacks Daniel Vetter
2013-01-10 20:48 ` [PATCH 25/35] drm: don't take modeset locks in getfb ioctl Daniel Vetter
2013-01-10 20:48 ` [PATCH 26/35] drm: fb refcounting for dirtyfb_ioctl Daniel Vetter
2013-01-10 20:48 ` [PATCH 27/35] drm: refcounting for sprite framebuffers Daniel Vetter
2013-01-10 20:48 ` [PATCH 28/35] drm: refcounting for crtc framebuffers Daniel Vetter
2013-01-10 20:48 ` [PATCH 29/35] drm/i915: dump refcount into framebuffer debugfs file Daniel Vetter
2013-01-11 22:20   ` Rob Clark
2013-01-10 20:48 ` [PATCH 30/35] drm/vmwgfx: add proper framebuffer refcounting Daniel Vetter
2013-01-10 20:48 ` [PATCH 31/35] drm: optimize drm_framebuffer_remove Daniel Vetter
2013-01-10 20:48 ` [PATCH 32/35] drm: only grab the crtc lock for pageflips Daniel Vetter
2013-01-10 20:48 ` [PATCH 33/35] drm: don't hold crtc mutexes for connector ->detect callbacks Daniel Vetter
2013-01-10 20:48 ` [PATCH 34/35] drm/doc: updates for new framebuffer lifetime rules Daniel Vetter
2013-01-10 20:48 ` [PATCH 35/35] drm/fb_helper: check whether fbcon is bound Daniel Vetter
2013-01-10 20:48 ` [PATCH 36/36] drm/i915: wake up all pageflip waiters Daniel Vetter
2013-01-10 20:50   ` Daniel Vetter
2013-01-11 23:17 ` [PATCH 00/36] kms locking rework Rob Clark

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