drm/etnaviv: add missing MMU context put when reaping MMU mapping

stable inclusion
from stable-5.10.68
commit cc9d96c9f9e009b8a33385fab9b78ccf92e51d6e
bugzilla: 182671 https://gitee.com/openeuler/kernel/issues/I4EWUH

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=cc9d96c9f9e009b8a33385fab9b78ccf92e51d6e

--------------------------------

commit f2faea8b upstream.

When we forcefully evict a mapping from the the address space and thus the
MMU context, the MMU context is leaked, as the mapping no longer points to
it, so it doesn't get freed when the GEM object is destroyed. Add the
mssing context put to fix the leak.

Cc: stable@vger.kernel.org # 5.4
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Tested-by: NMichael Walle <michael@walle.cc>
Tested-by: NMarek Vasut <marex@denx.de>
Reviewed-by: NChristian Gmeiner <christian.gmeiner@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Acked-by: NWeilong Chen <chenweilong@huawei.com>
Signed-off-by: NChen Jun <chenjun102@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

drivers/gpu/drm/etnaviv/etnaviv_mmu.c

@@ -197,6 +197,7 @@ static int etnaviv_iommu_find_iova(struct etnaviv_iommu_context *context,
 		 */
 		list_for_each_entry_safe(m, n, &list, scan_node) {
 			etnaviv_iommu_remove_mapping(context, m);
+			etnaviv_iommu_context_put(m->context);
 			m->context = NULL;
 			list_del_init(&m->mmu_node);
 			list_del_init(&m->scan_node);