From 99d5df36311e15d60a16f6cba6e3b4ca442b0472 Mon Sep 17 00:00:00 2001
From: Andrei Borzenkov <arvidjaar@gmail.com>
Date: Thu, 7 May 2015 20:37:17 +0300
Subject: efinet: open Simple Network Protocol exclusively

Patch-Name: efinet-open-Simple-Network-Protocol-exclusively.patch
Origin: upstream, http://git.savannah.gnu.org/cgit/grub.git/commit/?id=49426e9fd2e562c73a4f1206f32eff9e424a1a73
Bug-Ubuntu: https://bugs.launchpad.net/bugs/1508893
Last-Update: 2015-11-25
---
 grub-core/net/drivers/efi/efinet.c | 46 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/grub-core/net/drivers/efi/efinet.c b/grub-core/net/drivers/efi/efinet.c
index 2b344d6..658b3d1 100644
--- a/grub-core/net/drivers/efi/efinet.c
+++ b/grub-core/net/drivers/efi/efinet.c
@@ -130,9 +130,55 @@ get_card_packet (struct grub_net_card *dev)
   return nb;
 }
 
+static grub_err_t
+open_card (struct grub_net_card *dev)
+{
+  grub_efi_simple_network_t *net;
+
+  /* Try to reopen SNP exlusively to close any active MNP protocol instance
+     that may compete for packet polling
+   */
+  net = grub_efi_open_protocol (dev->efi_handle, &net_io_guid,
+				GRUB_EFI_OPEN_PROTOCOL_BY_EXCLUSIVE);
+  if (net)
+    {
+      if (net->mode->state == GRUB_EFI_NETWORK_STOPPED
+	  && efi_call_1 (net->start, net) != GRUB_EFI_SUCCESS)
+	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net start failed",
+			   dev->name);
+
+      if (net->mode->state == GRUB_EFI_NETWORK_STOPPED)
+	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: card stopped",
+			   dev->name);
+
+      if (net->mode->state == GRUB_EFI_NETWORK_STARTED
+	  && efi_call_3 (net->initialize, net, 0, 0) != GRUB_EFI_SUCCESS)
+	return grub_error (GRUB_ERR_NET_NO_CARD, "%s: net initialize failed",
+			   dev->name);
+
+      efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
+		  dev->efi_net, &net_io_guid,
+		  grub_efi_image_handle, dev->efi_handle);
+      dev->efi_net = net;
+    }
+
+  /* If it failed we just try to run as best as we can */
+  return GRUB_ERR_NONE;
+}
+
+static void
+close_card (struct grub_net_card *dev)
+{
+  efi_call_4 (grub_efi_system_table->boot_services->close_protocol,
+	      dev->efi_net, &net_io_guid,
+	      grub_efi_image_handle, dev->efi_handle);
+}
+
 static struct grub_net_card_driver efidriver =
   {
     .name = "efinet",
+    .open = open_card,
+    .close = close_card,
     .send = send_card_buffer,
     .recv = get_card_packet
   };