From: Jeff Kirsher Date: Fri, 3 Apr 2015 20:27:14 +0000 (-0700) Subject: fm10k: mbx_update_max_size does not drop all oversized messages X-Git-Tag: v4.14-rc1~5592^2^2~2 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=da61b36706f06a95bedeef0168db5b40a2940f8a;p=platform%2Fkernel%2Flinux-rpi.git fm10k: mbx_update_max_size does not drop all oversized messages 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 Signed-off-by: Jeff Kirsher --- 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) {