[PATCH master 2/3] fs: tftp: print message when NIC can't keep us with TFTP windowsize

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

When the NIC driver doesn't configure enough buffers to keep up
with a big TFTP windowsize, error reporting is less than optimal,
e.g. on Layerscape FMan:

  T BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBT T BBBBBBBBBBBBT
  BBBBBBBBBBBBBBBBBBBBBBBBBT

or on older DWMAC1000 (non-EQOS):

  WARNING: eth0: Rx error status (8800)
  T BBBBBBWARNING: eth0: Rx error status (8800)

While we probably want to increase ring buffer depth in the drivers of
these NICs, for now, at least print a helpful warning.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 fs/tftp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/tftp.c b/fs/tftp.c
index 0b0b86a1a07e..0f7a40e26abd 100644
--- a/fs/tftp.c
+++ b/fs/tftp.c
@@ -477,6 +477,8 @@ static void tftp_handle_data(struct file_priv *priv, uint16_t block,
 		/* completely unexpected and unrelated to actual window;
 		   ignore the packet. */
 		printf("B");
+		if (g_tftp_window_size > 1)
+			pr_warn_once("Unexpected packet. global.tftp.windowsize too high for NIC?\n");
 	} else {
 		/* The 'rc < 0' below happens e.g. when datagrams in the first
 		   part of the transfer window are dropped.
-- 
2.30.2