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 <[email protected]>
---
drivers/gpu/drm/qxl/qxl_release.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
index 716d706ca7f0..f5845c96d414 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);
--
2.29.2
Am 17.02.21 um 13:32 schrieb Gerd Hoffmann:
> 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 <[email protected]>
Acked-by: Thomas Zimmermann <[email protected]>
> ---
> drivers/gpu/drm/qxl/qxl_release.c | 13 ++++++++++---
> 1 file changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/qxl/qxl_release.c b/drivers/gpu/drm/qxl/qxl_release.c
> index 716d706ca7f0..f5845c96d414 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);
>
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer