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From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Boris Ostrovsky <boris.ostrovsky@oracle.com>,
	Juergen Gross <jgross@suse.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	Chris Wilson <chris@chris-wilson.co.uk>,
	Matthew Auld <matthew.auld@intel.com>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Minchan Kim <minchan@kernel.org>,
	Matthew Wilcox <willy@infradead.org>,
	Nitin Gupta <ngupta@vflare.org>,
	x86@kernel.org, xen-devel@lists.xenproject.org,
	linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-mm@kvack.org
Subject: [PATCH 04/10] mm: allow a NULL fn callback in apply_to_page_range
Date: Wed, 30 Sep 2020 19:51:27 +0200
Message-ID: <20200930175133.1252382-5-hch@lst.de> (raw)
In-Reply-To: <20200930175133.1252382-1-hch@lst.de>

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>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/memory.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index fcfc4ca36eba80..dcf2bb69fbf847 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2420,13 +2420,15 @@ static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
 
 	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();
-- 
2.28.0


  parent reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-30 17:51 remove alloc_vm_area v3 Christoph Hellwig
2020-09-30 17:51 ` [PATCH 01/10] mm: update the documentation for vfree Christoph Hellwig
2020-09-30 17:51 ` [PATCH 02/10] mm: add a VM_MAP_PUT_PAGES flag for vmap Christoph Hellwig
2020-09-30 17:51 ` [PATCH 03/10] mm: add a vmap_pfn function Christoph Hellwig
2020-09-30 17:51 ` Christoph Hellwig [this message]
2020-09-30 17:51 ` [PATCH 05/10] zsmalloc: switch from alloc_vm_area to get_vm_area Christoph Hellwig
2020-09-30 17:51 ` [PATCH 06/10] drm/i915: use vmap in shmem_pin_map Christoph Hellwig
2020-09-30 17:51 ` [PATCH 07/10] drm/i915: use vmap in i915_gem_object_map Christoph Hellwig
2020-09-30 17:51 ` [PATCH 08/10] xen/xenbus: use apply_to_page_range directly in xenbus_map_ring_pv Christoph Hellwig
2020-09-30 17:51 ` [PATCH 09/10] x86/xen: open code alloc_vm_area in arch_gnttab_valloc Christoph Hellwig
2020-09-30 17:51 ` [PATCH 10/10] mm: remove alloc_vm_area Christoph Hellwig

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