Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Anthony Yznaga <anthony.yznaga@oracle.com>
To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc:     willy@infradead.org, corbet@lwn.net, tglx@linutronix.de,
        mingo@redhat.com, bp@alien8.de, x86@kernel.org, hpa@zytor.com,
        dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org,
        rppt@linux.ibm.com, akpm@linux-foundation.org, hughd@google.com,
        ebiederm@xmission.com, masahiroy@kernel.org, ardb@kernel.org,
        ndesaulniers@google.com, dima@golovin.in, daniel.kiper@oracle.com,
        nivedita@alum.mit.edu, rafael.j.wysocki@intel.com,
        dan.j.williams@intel.com, zhenzhong.duan@oracle.com,
        jroedel@suse.de, bhe@redhat.com, guro@fb.com,
        Thomas.Lendacky@amd.com, andriy.shevchenko@linux.intel.com,
        keescook@chromium.org, hannes@cmpxchg.org, minchan@kernel.org,
        mhocko@kernel.org, ying.huang@intel.com,
        yang.shi@linux.alibaba.com, gustavo@embeddedor.com,
        ziqian.lzq@antfin.com, vdavydov.dev@gmail.com,
        jason.zeng@intel.com, kevin.tian@intel.com, zhiyuan.lv@intel.com,
        lei.l.li@intel.com, paul.c.lai@intel.com, ashok.raj@intel.com,
        linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org,
        kexec@lists.infradead.org
Subject: [RFC 20/43] PKRAM: disable feature when running the kdump kernel
Date:   Wed,  6 May 2020 17:41:46 -0700
Message-Id: <1588812129-8596-21-git-send-email-anthony.yznaga@oracle.com>
In-Reply-To: <1588812129-8596-1-git-send-email-anthony.yznaga@oracle.com>
References: <1588812129-8596-1-git-send-email-anthony.yznaga@oracle.com>
Sender: linux-kernel-owner@vger.kernel.org
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 95e691382721..4d4d836fea53 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>
@@ -193,7 +194,7 @@ 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");
@@ -305,6 +306,9 @@ 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;
@@ -1223,7 +1227,7 @@ 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);
 		sysfs_update_group(kernel_kobj, &pkram_attr_group);
-- 
2.13.3