[PATCH 6/7] drm: Don't walk fb list twice in getresources

From: Daniel Vetter <daniel.vetter@ffwll.ch>
To: DRI Development <dri-devel@lists.freedesktop.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>,
	Daniel Vetter <daniel.vetter@intel.com>
Subject: [PATCH 6/7] drm: Don't walk fb list twice in getresources
Date: Fri,  9 Dec 2016 15:19:43 +0100	[thread overview]
Message-ID: <20161209141944.22121-6-daniel.vetter@ffwll.ch> (raw)
In-Reply-To: <20161209141944.22121-1-daniel.vetter@ffwll.ch>

We can be more clever than that and merge the 2 list walking loops.
It's all under the one mutex critical section anyway, so nothing funny
can happen.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
 drivers/gpu/drm/drm_mode_config.c | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
index 64c2971478db..a6205a92dfee 100644
--- a/drivers/gpu/drm/drm_mode_config.c
+++ b/drivers/gpu/drm/drm_mode_config.c
@@ -84,7 +84,6 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 			  struct drm_file *file_priv)
 {
 	struct drm_mode_card_res *card_res = data;
-	struct list_head *lh;
 	struct drm_framebuffer *fb;
 	struct drm_connector *connector;
 	struct drm_crtc *crtc;
@@ -105,25 +104,20 @@ int drm_mode_getresources(struct drm_device *dev, void *data,
 
 
 	mutex_lock(&file_priv->fbs_lock);
-	/*
-	 * For the non-control nodes we need to limit the list of resources
-	 * by IDs in the group list for this node
-	 */
-	list_for_each(lh, &file_priv->fbs)
-		fb_count++;
-
 	/* handle this in 4 parts */
 	/* FBs */
-	if (card_res->count_fbs >= fb_count) {
-		copied = 0;
-		fb_id = (uint32_t __user *)(unsigned long)card_res->fb_id_ptr;
-		list_for_each_entry(fb, &file_priv->fbs, filp_head) {
-			if (put_user(fb->base.id, fb_id + copied)) {
-				mutex_unlock(&file_priv->fbs_lock);
-				return -EFAULT;
-			}
-			copied++;
+	copied = 0;
+	fb_id = (uint32_t __user *)(unsigned long)card_res->fb_id_ptr;
+	list_for_each_entry(fb, &file_priv->fbs, filp_head) {
+		fb_count++;
+		if (fb_count > card_res->count_fbs)
+			continue;
+
+		if (put_user(fb->base.id, fb_id + copied)) {
+			mutex_unlock(&file_priv->fbs_lock);
+			return -EFAULT;
 		}
+		copied++;
 	}
 	card_res->count_fbs = fb_count;
 	mutex_unlock(&file_priv->fbs_lock);
-- 
2.10.2

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