diff mbox series

[30/40] mm: allow a NULL fn callback in apply_to_page_range

Message ID 20201017231514.wi5ZbtIfe%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [01/40] ia64: fix build error with !COREDUMP | expand

Commit Message

Andrew Morton Oct. 17, 2020, 11:15 p.m. UTC 
From: Christoph Hellwig <hch@lst.de>
Subject: mm: allow a NULL fn callback in apply_to_page_range

Besides calling the callback on each page, apply_to_page_range also has
the effect of pre-faulting all PTEs for the range.  To support callers
that only need the pre-faulting, make the callback optional.

Based on a patch from Minchan Kim <minchan@kernel.org>.

Link: https://lkml.kernel.org/r/20201002122204.1534411-5-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/memory.c |   16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)
diff mbox series

Patch

--- a/mm/memory.c~mm-allow-a-null-fn-callback-in-apply_to_page_range
+++ a/mm/memory.c
@@ -2391,13 +2391,15 @@  static int apply_to_pte_range(struct mm_
 
 	arch_enter_lazy_mmu_mode();
 
-	do {
-		if (create || !pte_none(*pte)) {
-			err = fn(pte++, addr, data);
-			if (err)
-				break;
-		}
-	} while (addr += PAGE_SIZE, addr != end);
+	if (fn) {
+		do {
+			if (create || !pte_none(*pte)) {
+				err = fn(pte++, addr, data);
+				if (err)
+					break;
+			}
+		} while (addr += PAGE_SIZE, addr != end);
+	}
 	*mask |= PGTBL_PTE_MODIFIED;
 
 	arch_leave_lazy_mmu_mode();