[Intel-wired-lan] [net-next 24/25] fm10k: mbx_update_max_size does not drop all oversized messages
jeffrey.t.kirsher at intel.com
Fri Apr 3 20:27:14 UTC 2015
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 at intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller at intel.com>
Acked-by: Matthew Vick <matthew.vick at intel.com>
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
@@ -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 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)
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