From mboxrd@z Thu Jan 1 00:00:00 1970 From: tndave Subject: i40e: Kernel unaligned access due to 'struct i40e_dma_mem' being 'packed' Date: Wed, 27 Jan 2016 17:50:14 -0800 Message-ID: <56A973D6.4060202@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: tushar.n.dave@oracle.com To: netdev@vger.kernel.org, "Kirsher, Jeffrey T" , "Brandeburg, Jesse" , "Nelson, Shannon" , "Wyborny, Carolyn" , "Skidmore, Donald C" , "Allan, Bruce W" , "Ronciak, John" , mitch.a.williams@intel.com, intel-wired-lan@lists.osuosl.org Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:18763 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932213AbcA1BuT (ORCPT ); Wed, 27 Jan 2016 20:50:19 -0500 Sender: netdev-owner@vger.kernel.org List-ID: Hi, i40e driver has 'struct i40e_dma_mem' defined with 'packed' directive causing kernel unaligned errors on sparc (when 40e_allocate_dma_mem_d() is being called) log_unaligned: 1031 callbacks suppressed Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0 Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0 Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0 Kernel unaligned access at TPC[448ae8] dma_4v_alloc_coherent+0x188/0x2e0 This can be fixed with get_unaligned/put_unaligned(). However I don't see 'struct i40e_dma_mem' is being directly shoved into NIC hardware. But instead fields of the struct are being read and used for hardware (e.g. dma_addr_t pa). For the test, I remove __packed, and i40e driver and HW works fine. (of course kernel unaligned errors are gone too). My question is, does 'struct i40e_dma_mem' required to be __packed? Thanks. -Tushar