mlxsw: spectrum_acl: Remove failed_rollback dead end

Currently if a rollback ends with error, the vregion is in a zombie
state until end of the existence. Instead of that, rather try to
continue where rollback ended later on (after rehash interval).

Signed-off-by: Jiri Pirko <[e-mail]>
Signed-off-by: Ido Schimmel <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c

···
 		struct mlxsw_sp_acl_tcam_rehash_ctx ctx;
 	} rehash;
 	struct mlxsw_sp *mlxsw_sp;
-	bool failed_rollback; /* Indicates failed rollback during migration */
 	unsigned int ref_count;
 };
 
···
 		err = mlxsw_sp_acl_tcam_ventry_migrate(mlxsw_sp, ventry,
 						       vchunk->chunk, credits);
 		if (err) {
-			if (ctx->this_is_rollback)
+			if (ctx->this_is_rollback) {
+				/* Save the ventry which we ended with and try
+				 * to continue later on.
+				 */
+				ctx->start_ventry = ventry;
 				return err;
+			}
 			/* Swap the chunk and chunk2 pointers so the follow-up
 			 * rollback call will see the original chunk pointer
 			 * in vchunk->chunk.
···
 		err2 = mlxsw_sp_acl_tcam_vchunk_migrate_all(mlxsw_sp, vregion,
 							    ctx, credits);
 		if (err2) {
-			vregion->failed_rollback = true;
 			trace_mlxsw_sp_acl_tcam_vregion_rehash_dis(mlxsw_sp,
 								   vregion);
 			dev_err(mlxsw_sp->bus_info->dev, "Failed to rollback during vregion migration fail\n");
+			/* Let the rollback to be continued later on. */
 		}
 	}
 	mutex_unlock(&vregion->lock);
···
 	int err;
 
 	trace_mlxsw_sp_acl_tcam_vregion_rehash(mlxsw_sp, vregion);
-	if (vregion->failed_rollback)
-		return -EBUSY;
 
 	hints_priv = ops->region_rehash_hints_get(vregion->region->priv);
 	if (IS_ERR(hints_priv))
···
 	struct mlxsw_sp_acl_tcam_region *unused_region = vregion->region2;
 	const struct mlxsw_sp_acl_tcam_ops *ops = mlxsw_sp->acl_tcam_ops;
 
-	if (!vregion->failed_rollback) {
-		vregion->region2 = NULL;
-		mlxsw_sp_acl_tcam_group_region_detach(mlxsw_sp, unused_region);
-		mlxsw_sp_acl_tcam_region_destroy(mlxsw_sp, unused_region);
-	}
+	vregion->region2 = NULL;
+	mlxsw_sp_acl_tcam_group_region_detach(mlxsw_sp, unused_region);
+	mlxsw_sp_acl_tcam_region_destroy(mlxsw_sp, unused_region);
 	ops->region_rehash_hints_put(ctx->hints_priv);
 	ctx->hints_priv = NULL;
 }