[PATCH 2/2] drm/etnaviv: reap idle mapping if it doesn't match the softpin address

[Lucas Stach]

When a idle BO, which is held open by another process, gets freed by
userspace and subsequently referenced again by e.g. importing it again,
userspace may assign a different softpin VA than the last time around.
As the kernel GEM object still exists, we likely have a idle mapping
with the old VA still cached, if it hasn't been reaped in the meantime.

As the context matches, we then simply try to resurrect this mapping by
increasing the refcount. As the VA in this mapping does not match the
new softpin address, we consequently fail the otherwise valid submit.
Instead of failing, reap the idle mapping.

Cc: stable at vger.kernel.org # 5.19
Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
---
 drivers/gpu/drm/etnaviv/etnaviv_gem.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.c b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
index cc386f8a7116..5cf13e52f7c9 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.c
@@ -258,7 +258,12 @@ struct etnaviv_vram_mapping *etnaviv_gem_mapping_get(
 		if (mapping->use == 0) {
 			mutex_lock(&mmu_context->lock);
 			if (mapping->context == mmu_context)
-				mapping->use += 1;
+				if (va && mapping->iova != va) {
+					etnaviv_iommu_reap_mapping(mapping);
+					mapping = NULL;
+				} else {
+					mapping->use += 1;
+				}
 			else
 				mapping = NULL;
 			mutex_unlock(&mmu_context->lock);
-- 
2.30.2