From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wang Xiao W Subject: [PATCH v3 15/18] fm10k/base: fix TLV structures alignment Date: Fri, 19 Feb 2016 19:07:02 +0800 Message-ID: <1455880025-6912-16-git-send-email-xiao.w.wang@intel.com> References: <1453866647-16215-2-git-send-email-xiao.w.wang@intel.com> <1455880025-6912-1-git-send-email-xiao.w.wang@intel.com> Cc: dev@dpdk.org To: jing.d.chen@intel.com Return-path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 60F5BC55A for ; Fri, 19 Feb 2016 12:08:48 +0100 (CET) In-Reply-To: <1455880025-6912-1-git-send-email-xiao.w.wang@intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Per comments from an upstream patch, and looking at how TLV LE_STRUCT code works, we actually want these structures to be 4byte aligned, not 1byte aligned. In practice, 1byte alignment has worked so far because all our structures end up being a multiple of 4. But if a future TLV structure were added that had a u8 or similar sticking on the end things would break. Fix this by using 4byte alignment which will prevent the TLV LE_STRUCT code from breaking. Update the comment explaining that we need 4byte alignment of our structures. Fixes: e24fed68236a ("fm10k: pack TLV overlay structures correctly") Signed-off-by: Wang Xiao W --- drivers/net/fm10k/base/fm10k_pf.h | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/net/fm10k/base/fm10k_pf.h b/drivers/net/fm10k/base/fm10k_pf.h index 92e2962..ee8527a 100644 --- a/drivers/net/fm10k/base/fm10k_pf.h +++ b/drivers/net/fm10k/base/fm10k_pf.h @@ -91,14 +91,14 @@ enum fm10k_pf_tlv_attr_id_v1 { #define FM10K_MSG_UPDATE_PVID_PVID_SHIFT 16 #define FM10K_MSG_UPDATE_PVID_PVID_SIZE 16 -/* The following data structures are overlayed specifically to TLV mailbox - * messages, and must not have gaps between their values. They must line up - * correctly to the TLV definition. +/* The following data structures are overlayed directly onto TLV mailbox + * messages, and must not break 4 byte alignment. Ensure the structures line + * up correctly as per their TLV definition. */ #ifdef C99 -#pragma pack(push, 1) +#pragma pack(push, 4) #else -#pragma pack(1) +#pragma pack(4) #endif /* C99 */ struct fm10k_mac_update { -- 1.9.3