From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 23/25] fm10k: mbx_update_max_size does not drop all oversized messages Date: Tue, 14 Apr 2015 16:51:09 -0700 Message-ID: <1429055471-401-24-git-send-email-jeffrey.t.kirsher@intel.com> References: <1429055471-401-1-git-send-email-jeffrey.t.kirsher@intel.com> Cc: Jeff Kirsher , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com, Jacob Keller To: davem@davemloft.net Return-path: Received: from mga11.intel.com ([192.55.52.93]:20409 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755106AbbDNXva (ORCPT ); Tue, 14 Apr 2015 19:51:30 -0400 In-Reply-To: <1429055471-401-1-git-send-email-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: When we call update_max_size it does not drop all oversized messages. This is due to the difficulty in performing this operation, since it is a FIFO which makes updating anything other than head or tail very difficult. To fix this, modify validate_msg_size to ensure that we error out later when trying to transmit the message that could be oversized. This will generally be a rare condition, as it requires the FIFO to include a message larger than the max_size negotiated during mailbox connect. Note that max_size is always smaller than rx.size so it should be safe to use here. Also, update the update_max_size function header comment to clearly indicate that it does not drop all oversized messages, but only those at the head of the FIFO. Signed-off-by: Jeff Kirsher Signed-off-by: Jacob Keller Acked-by: Matthew Vick Tested-by: Krishneil Singh --- drivers/net/ethernet/intel/fm10k/fm10k_mbx.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_mbx.c b/drivers/net/ethernet/intel/fm10k/fm10k_mbx.c index 27f8279..1b27383 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_mbx.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_mbx.c @@ -327,7 +327,7 @@ static u16 fm10k_mbx_validate_msg_size(struct fm10k_mbx_info *mbx, u16 len) } while (total_len < len); /* message extends out of pushed section, but fits in FIFO */ - if ((len < total_len) && (msg_len <= mbx->rx.size)) + if ((len < total_len) && (msg_len <= mbx->max_size)) return 0; /* return length of invalid section */ @@ -1063,8 +1063,11 @@ static void fm10k_mbx_reset_work(struct fm10k_mbx_info *mbx) * @mbx: pointer to mailbox * @size: new value for max_size * - * This function will update the max_size value and drop any outgoing messages - * from the head of the Tx FIFO that are larger than max_size. + * This function updates the max_size value and drops any outgoing messages + * at the head of the Tx FIFO if they are larger than max_size. It does not + * drop all messages, as this is too difficult to parse and remove them from + * the FIFO. Instead, rely on the checking to ensure that messages larger + * than max_size aren't pushed into the memory buffer. **/ static void fm10k_mbx_update_max_size(struct fm10k_mbx_info *mbx, u16 size) { -- 1.9.3