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From:   Anthony Yznaga <anthony.yznaga@oracle.com>
To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
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Subject: [RFC v3 19/21] PKRAM: disable feature when running the kdump kernel
Date:   Wed, 26 Apr 2023 17:08:55 -0700
Message-Id: <1682554137-13938-20-git-send-email-anthony.yznaga@oracle.com>
In-Reply-To: <1682554137-13938-1-git-send-email-anthony.yznaga@oracle.com>
References: <1682554137-13938-1-git-send-email-anthony.yznaga@oracle.com>
Precedence: bulk

The kdump kernel should not preserve or restore pages.

Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
---
 mm/pkram.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/pkram.c b/mm/pkram.c
index d404e415f3cb..f38236e5d836 100644
--- a/mm/pkram.c
+++ b/mm/pkram.c
@@ -1,4 +1,5 @@
 // SPDX-License-Identifier: GPL-2.0
+#include <linux/crash_dump.h>
 #include <linux/err.h>
 #include <linux/gfp.h>
 #include <linux/highmem.h>
@@ -188,7 +189,7 @@ void __init pkram_reserve(void)
 {
 	int err = 0;
 
-	if (!pkram_sb_pfn)
+	if (!pkram_sb_pfn || is_kdump_kernel())
 		return;
 
 	pr_info("PKRAM: Examining preserved memory...\n");
@@ -285,6 +286,9 @@ static void pkram_show_banned(void)
 	int i;
 	unsigned long n, total = 0;
 
+	if (is_kdump_kernel())
+		return;
+
 	pr_info("PKRAM: banned regions:\n");
 	for (i = 0; i < nr_banned; i++) {
 		n = banned[i].end - banned[i].start + 1;
@@ -1334,7 +1338,7 @@ static int __init pkram_init_sb(void)
 
 static int __init pkram_init(void)
 {
-	if (pkram_init_sb()) {
+	if (!is_kdump_kernel() && pkram_init_sb()) {
 		register_reboot_notifier(&pkram_reboot_notifier);
 		register_shrinker(&banned_pages_shrinker, "pkram");
 		sysfs_update_group(kernel_kobj, &pkram_attr_group);
-- 
1.9.4