From bd1d37e3536136130df41ac8162ce5bb4f361f87 Mon Sep 17 00:00:00 2001
From: Thomas Huth <thuth@redhat.com>
Date: Tue, 1 Jun 2021 08:52:10 -0400
Subject: [PATCH 02/21] pc-bios/s390-ccw: don't try to read the next block if
 end of chunk is reached
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RH-Author: Miroslav Rezanina <mrezanin@redhat.com>
RH-MergeRequest: 8: Synchronize with RHEL-AV 8.5 release 19 to RHEL 9
RH-Commit: [1/8] 69a43520a9e7f0ab92bdfdc47281c7606f5159e7 (mrezanin/centos-src-qemu-kvm)
RH-Bugzilla: 1957194
RH-Acked-by: Daniel P. Berrangé <berrange@redhat.com>
RH-Acked-by: Greg Kurz <gkurz@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Vitaly Kuznetsov <vkuznets@redhat.com>

From: Marc Hartmayer <mhartmay@linux.ibm.com>

Don't read the block if a null block number is reached, because this means that
the end of chunk is reached.

Reviewed-by: Collin Walling <walling@linux.ibm.com>
Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
Message-Id: <20210416074736.17409-1-mhartmay@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
(cherry picked from commit a6625d38cce3901a7c1cba069f0abcf743a293f1)
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 pc-bios/s390-ccw/bootmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pc-bios/s390-ccw/bootmap.c b/pc-bios/s390-ccw/bootmap.c
index 44df7d16af..b46997c0b7 100644
--- a/pc-bios/s390-ccw/bootmap.c
+++ b/pc-bios/s390-ccw/bootmap.c
@@ -213,7 +213,7 @@ static int eckd_get_boot_menu_index(block_number_t s1b_block_nr)
                 next_block_nr = eckd_block_num(&s1b->seek[i + 1].chs);
             }
 
-            if (next_block_nr) {
+            if (next_block_nr && !is_null_block_number(next_block_nr)) {
                 read_block(next_block_nr, s2_next_blk,
                            "Cannot read stage2 boot loader");
             }
-- 
2.27.0