grub2/0070-efinet-retransmit-if-our-device-is-busy.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Josef Bacik <jbacik@fb.com>
Date: Mon, 31 Aug 2015 13:34:35 -0400
Subject: [PATCH] efinet: retransmit if our device is busy

When I fixed the txbuf handling I ripped out the retransmission code since it
was flooding our network when we had the buggy behavior.  Turns out this was too
heavy handed as we can still have transient tx timeouts.  So instead make sure
we retry our transmission once per timeout.  This way we can deal with transient
transmission problems without flooding the box.  This fixes an issue we were
seeing in production.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
---
 grub-core/net/drivers/efi/efinet.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index 5388f952ba9..3f112438a93 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -38,6 +38,7 @@ send_card_buffer (struct grub_net_card *dev,
   grub_efi_simple_network_t *net = dev->efi_net;
   grub_uint64_t limit_time = grub_get_time_ms () + 4000;
   void *txbuf;
+  int retry = 0;
 
   if (dev->txbusy)
     while (1)
@@ -60,6 +61,15 @@ send_card_buffer (struct grub_net_card *dev,
 	    dev->txbusy = 0;
 	    break;
 	  }
+	if (!retry)
+	  {
+	    st = efi_call_7 (net->transmit, net, 0, dev->last_pkt_size,
+			     dev->txbuf, NULL, NULL, NULL);
+	    if (st != GRUB_EFI_SUCCESS)
+	      return grub_error (GRUB_ERR_IO,
+				 N_("couldn't send network packet"));
+	    retry = 1;
+	  }
 	if (limit_time < grub_get_time_ms ())
 	  return grub_error (GRUB_ERR_TIMEOUT,
 			     N_("couldn't send network packet"));