diff mbox series

[RFC,v1,11/12] x86/mm: Prepare __ioremap_check_ram() for PG_reserved changes

Message ID 20191022171239.21487-12-david@redhat.com (mailing list archive)
State New, archived
Headers show
Series mm: Don't mark hotplugged pages PG_reserved (including ZONE_DEVICE) | expand

Commit Message

David Hildenbrand Oct. 22, 2019, 5:12 p.m. UTC 
Right now, ZONE_DEVICE memory is always set PG_reserved. We want to
change that.

We could explicitly check for is_zone_device_page(page). But looking at
the pfn_valid() check, it seems safer to just use pfn_to_online_page()
here, that will skip all ZONE_DEVICE pages right away.

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 arch/x86/mm/ioremap.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
index a39dcdb5ae34..db6913b48edf 100644
--- a/arch/x86/mm/ioremap.c
+++ b/arch/x86/mm/ioremap.c
@@ -77,10 +77,17 @@  static unsigned int __ioremap_check_ram(struct resource *res)
 	start_pfn = (res->start + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	stop_pfn = (res->end + 1) >> PAGE_SHIFT;
 	if (stop_pfn > start_pfn) {
-		for (i = 0; i < (stop_pfn - start_pfn); ++i)
-			if (pfn_valid(start_pfn + i) &&
-			    !PageReserved(pfn_to_page(start_pfn + i)))
+		for (i = 0; i < (stop_pfn - start_pfn); ++i) {
+			struct page *page;
+			 /*
+			  * We treat any pages that are not online (not managed
+			  * by the buddy) as not being RAM. This includes
+			  * ZONE_DEVICE pages.
+			  */
+			page = pfn_to_online_page(start_pfn + i);
+			if (page && !PageReserved(page))
 				return IORES_MAP_SYSTEM_RAM;
+		}
 	}
 
 	return 0;