FAILED: patch "[PATCH] drm/xe/rtp: Ensure locking/ref counting for OA whitelists" failed to apply to 6.12-stable tree

The patch below does not apply to the 6.12-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x ef78e2a22f72c892fd6663f0760abd208d49a3e2
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026072915-scratch-tavern-3987@gregkh' --subject-prefix 'PATCH 6.12.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ef78e2a22f72c892fd6663f0760abd208d49a3e2 Mon Sep 17 00:00:00 2001
From: Ashutosh Dixit <[email protected]>
Date: Mon, 15 Jun 2026 15:42:27 -0700
Subject: [PATCH] drm/xe/rtp: Ensure locking/ref counting for OA whitelists
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Since multiple OA streams might be open in parallel on a gt, ensure that proper locking is in place. Also ensure that OA registers are whitelisted when the first OA stream is open and de-whitelisted after the last OA stream is closed.

index 3d9ec8490899..e876e9be92ba 100644
@@ -126,6 +126,9 @@ struct xe_oa_gt {
 
 	/** @oa_unit: array of oa_units */
 	struct xe_oa_unit *oa_unit;
+
+	/** @whitelist_count: number of open streams for which oa registers are whitelisted */
+	u32 whitelist_count;
 };
 
 /**

index b2e7aabd19d7..3d9e3daab01a 100644
@@ -255,6 +255,10 @@ void xe_reg_whitelist_oa_regs(struct xe_gt *gt)
 	struct xe_hw_engine *hwe;
 	enum xe_hw_engine_id id;
 
+	lockdep_assert_held(&gt->oa.gt_lock);
+	if (gt->oa.whitelist_count++)
+		return;
+
 	for_each_hw_engine(hwe, gt, id)
 		__whitelist_oa_regs(hwe, true);
 }

@@ -270,6 +274,11 @@ void xe_reg_dewhitelist_oa_regs(struct xe_gt *gt)
 	struct xe_hw_engine *hwe;
 	enum xe_hw_engine_id id;
 
+	lockdep_assert_held(&gt->oa.gt_lock);
+	xe_assert(gt_to_xe(gt), gt->oa.whitelist_count);
+	if (--gt->oa.whitelist_count)
+		return;
+
 	for_each_hw_engine(hwe, gt, id)
 		__whitelist_oa_regs(hwe, false);
 }