KVM: s390: Fix leaking kvm_s390_mmu_cache in case of errors

Fix a memory leak that can happen if gmap_ucas_map_one() or
kvm_s390_mmu_cache_topup() return error values.

Also fix a similar issue in gmap_set_limit().

Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: a2c17f9 ("KVM: s390: New gmap code")
Reported-by: Jiaxin Fan <jiaxin.fan@ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

Author: Claudio Imbrenda

arch/s390/kvm/gmap.c

@@ -125,7 +125,7 @@ struct gmap *gmap_new_child(struct gmap *parent, gfn_t limit)
 
 int gmap_set_limit(struct gmap *gmap, gfn_t limit)
 {
-	struct kvm_s390_mmu_cache *mc;
+	struct kvm_s390_mmu_cache *mc __free(kvm_s390_mmu_cache) = NULL;
 	int rc, type;
 
 	type = gmap_limit_to_type(limit);
@@ -142,7 +142,6 @@ int gmap_set_limit(struct gmap *gmap, gfn_t limit)
 			rc = dat_set_asce_limit(mc, &gmap->asce, type);
 	} while (rc == -ENOMEM);
 
-	kvm_s390_free_mmu_cache(mc);
 	return 0;
 }
 
@@ -822,8 +821,8 @@ int gmap_ucas_translate(struct kvm_s390_mmu_cache *mc, struct gmap *gmap, gpa_t
 
 int gmap_ucas_map(struct gmap *gmap, gfn_t p_gfn, gfn_t c_gfn, unsigned long count)
 {
-	struct kvm_s390_mmu_cache *mc;
-	int rc;
+	struct kvm_s390_mmu_cache *mc __free(kvm_s390_mmu_cache) = NULL;
+	int rc = 0;
 
 	mc = kvm_s390_new_mmu_cache();
 	if (!mc)