From: Gerd Hoffmann <kraxel@redhat.com>
Date: Wed, 17 Feb 2021 12:32:06 +0000 (+0100)
Subject: drm/qxl: fix lockdep issue in qxl_alloc_release_reserved
X-Git-Tag: v5.13-rc1~123^2~14^2~60
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=19089b760e56c97458c272e90e43da761b05cf12;p=thirdparty%2Flinux.git

drm/qxl: fix lockdep issue in qxl_alloc_release_reserved

Call qxl_bo_unpin (which does a reservation) without holding the
release_mutex lock.  Fixes lockdep (correctly) warning on a possible
deadlock.

Fixes: 65ffea3c6e73 ("drm/qxl: unpin release objects")
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20210217123213.2199186-5-kraxel@redhat.com
---

diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 716d706ca7f09..f5845c96d4147 100644
--- a/drivers/gpu/drm/qxl/qxl_release.c
+++ b/drivers/gpu/drm/qxl/qxl_release.c
@@ -283,7 +283,7 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
 				       int type, struct qxl_release **release,
 				       struct qxl_bo **rbo)
 {
-	struct qxl_bo *bo;
+	struct qxl_bo *bo, *free_bo = NULL;
 	int idr_ret;
 	int ret = 0;
 	union qxl_release_info *info;
@@ -315,8 +315,7 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
 
 	mutex_lock(&qdev->release_mutex);
 	if (qdev->current_release_bo_offset[cur_idx] + 1 >= releases_per_bo[cur_idx]) {
-		qxl_bo_unpin(qdev->current_release_bo[cur_idx]);
-		qxl_bo_unref(&qdev->current_release_bo[cur_idx]);
+		free_bo = qdev->current_release_bo[cur_idx];
 		qdev->current_release_bo_offset[cur_idx] = 0;
 		qdev->current_release_bo[cur_idx] = NULL;
 	}
@@ -324,6 +323,10 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
 		ret = qxl_release_bo_alloc(qdev, &qdev->current_release_bo[cur_idx], priority);
 		if (ret) {
 			mutex_unlock(&qdev->release_mutex);
+			if (free_bo) {
+				qxl_bo_unpin(free_bo);
+				qxl_bo_unref(&free_bo);
+			}
 			qxl_release_free(qdev, *release);
 			return ret;
 		}
@@ -339,6 +342,10 @@ int qxl_alloc_release_reserved(struct qxl_device *qdev, unsigned long size,
 		*rbo = bo;
 
 	mutex_unlock(&qdev->release_mutex);
+	if (free_bo) {
+		qxl_bo_unpin(free_bo);
+		qxl_bo_unref(&free_bo);
+	}
 
 	ret = qxl_release_list_add(*release, bo);
 	qxl_bo_unref(&bo);