linux-kernel - [RFC v3 12/21] PKRAM: free the preserved ranges list

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Date:   Wed, 26 Apr 2023 17:08:48 -0700
From:   Anthony Yznaga <anthony.yznaga@...cle.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, x86@...nel.org,
        hpa@...or.com, dave.hansen@...ux.intel.com, luto@...nel.org,
        peterz@...radead.org, rppt@...nel.org, akpm@...ux-foundation.org,
        ebiederm@...ssion.com, keescook@...omium.org, graf@...zon.com,
        jason.zeng@...el.com, lei.l.li@...el.com,
        steven.sistare@...cle.com, fam.zheng@...edance.com,
        mgalaxy@...mai.com, kexec@...ts.infradead.org
Subject: [RFC v3 12/21] PKRAM: free the preserved ranges list

Free the pages used to pass the preserved ranges to the new boot.

Signed-off-by: Anthony Yznaga <anthony.yznaga@...cle.com>
---
 arch/x86/mm/init_64.c |  1 +
 include/linux/pkram.h |  2 ++
 mm/pkram.c            | 20 ++++++++++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
index a46ffb434f39..9e68f07367fa 100644
--- a/arch/x86/mm/init_64.c
+++ b/arch/x86/mm/init_64.c
@@ -1340,6 +1340,7 @@ void __init mem_init(void)
 	after_bootmem = 1;
 	x86_init.hyper.init_after_bootmem();
 
+	pkram_cleanup();
 	totalram_pages_add(pkram_reserved_pages);
 	/*
 	 * Must be done after boot memory is put on freelist, because here we
diff --git a/include/linux/pkram.h b/include/linux/pkram.h
index 53d5a1ec42ff..c909aa299fc4 100644
--- a/include/linux/pkram.h
+++ b/include/linux/pkram.h
@@ -102,9 +102,11 @@ int pkram_prepare_save(struct pkram_stream *ps, const char *name,
 #ifdef CONFIG_PKRAM
 extern unsigned long pkram_reserved_pages;
 void pkram_reserve(void);
+void pkram_cleanup(void);
 #else
 #define pkram_reserved_pages 0UL
 static inline void pkram_reserve(void) { }
+static inline void pkram_cleanup(void) { }
 #endif
 
 #endif /* _LINUX_PKRAM_H */
diff --git a/mm/pkram.c b/mm/pkram.c
index b711f94dbef4..c63b27bb711b 100644
--- a/mm/pkram.c
+++ b/mm/pkram.c
@@ -1456,3 +1456,23 @@ int __init pkram_merge_with_reserved(void)
 
 	return 0;
 }
+
+void __init pkram_cleanup(void)
+{
+	struct pkram_region_list *rl;
+	unsigned long next_pfn;
+
+	if (!pkram_sb || !pkram_reserved_pages)
+		return;
+
+	next_pfn = pkram_sb->region_list_pfn;
+
+	while (next_pfn) {
+		struct page *page = pfn_to_page(next_pfn);
+
+		rl = pfn_to_kaddr(next_pfn);
+		next_pfn = rl->next_pfn;
+		__free_pages_core(page, 0);
+		pkram_reserved_pages--;
+	}
+}
-- 
1.9.4