linux-kernel - [PATCH v3 kernel 3/7] mm: add a function to get the max pfn

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  8 Aug 2016 14:35:30 +0800
From:	Liang Li <liang.z.li@...el.com>
To:	linux-kernel@...r.kernel.org
Cc:	virtualization@...ts.linux-foundation.org, linux-mm@...ck.org,
	virtio-dev@...ts.oasis-open.org, kvm@...r.kernel.org,
	qemu-devel@...gnu.org, quintela@...hat.com, dgilbert@...hat.com,
	dave.hansen@...el.com, Liang Li <liang.z.li@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Mel Gorman <mgorman@...hsingularity.net>,
	"Michael S. Tsirkin" <mst@...hat.com>,
	Paolo Bonzini <pbonzini@...hat.com>,
	Cornelia Huck <cornelia.huck@...ibm.com>,
	Amit Shah <amit.shah@...hat.com>
Subject: [PATCH v3 kernel 3/7] mm: add a function to get the max pfn

Expose the function to get the max pfn, so it can be used in the
virtio-balloon device driver. Simply include the 'linux/bootmem.h'
is not enough, if the device driver is built to a module, directly
refer the max_pfn lead to build failed.

Signed-off-by: Liang Li <liang.z.li@...el.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Mel Gorman <mgorman@...hsingularity.net>
Cc: Michael S. Tsirkin <mst@...hat.com>
Cc: Paolo Bonzini <pbonzini@...hat.com>
Cc: Cornelia Huck <cornelia.huck@...ibm.com>
Cc: Amit Shah <amit.shah@...hat.com>
Cc: Dave Hansen <dave.hansen@...el.com>
---
 include/linux/mm.h |  1 +
 mm/page_alloc.c    | 10 ++++++++++
 2 files changed, 11 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 08ed53e..5873057 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1788,6 +1788,7 @@ extern void free_area_init(unsigned long * zones_size);
 extern void free_area_init_node(int nid, unsigned long * zones_size,
 		unsigned long zone_start_pfn, unsigned long *zholes_size);
 extern void free_initmem(void);
+extern unsigned long get_max_pfn(void);
 
 /*
  * Free reserved pages within range [PAGE_ALIGN(start), end & PAGE_MASK)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index fb975ce..3373704 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4391,6 +4391,16 @@ void show_free_areas(unsigned int filter)
 	show_swap_cache_info();
 }
 
+/*
+ * The max_pfn can change because of memory hot plug, so it's only good
+ * as a hint. e.g. for sizing data structures.
+ */
+unsigned long get_max_pfn(void)
+{
+	return max_pfn;
+}
+EXPORT_SYMBOL(get_max_pfn);
+
 static void zoneref_set_zone(struct zone *zone, struct zoneref *zoneref)
 {
 	zoneref->zone = zone;
-- 
1.8.3.1