Commit da61b367 authored Apr 03, 2015 by Jeff Kirsher

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 <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Matthew Vick <matthew.vick@intel.com>
Tested-by: Krishneil Singh <krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

parent 78288e37

drivers/net/ethernet/intel/fm10k/fm10k_mbx.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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)
		{