diff mbox series

[25/27] mm: remove the vma check in migrate_vma_setup()

Message ID 20220210072828.2930359-26-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series [01/27] mm: remove a pointless CONFIG_ZONE_DEVICE check in memremap_pages | expand

Commit Message

Christoph Hellwig Feb. 10, 2022, 7:28 a.m. UTC 
From: Alistair Popple <apopple@nvidia.com>

migrate_vma_setup() checks that a valid vma is passed so that the page
tables can be walked to find the pfns associated with a given address
range. However in some cases the pfns are already known, such as when
migrating device coherent pages during pin_user_pages() meaning a valid
vma isn't required.

Signed-off-by: Alistair Popple <apopple@nvidia.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 mm/migrate_device.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)
diff mbox series

Patch

diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index 0b295594e7626d..03e182f9fc7865 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c
@@ -462,24 +462,24 @@  int migrate_vma_setup(struct migrate_vma *args)
 
 	args->start &= PAGE_MASK;
 	args->end &= PAGE_MASK;
-	if (!args->vma || is_vm_hugetlb_page(args->vma) ||
-	    (args->vma->vm_flags & VM_SPECIAL) || vma_is_dax(args->vma))
-		return -EINVAL;
-	if (nr_pages <= 0)
-		return -EINVAL;
-	if (args->start < args->vma->vm_start ||
-	    args->start >= args->vma->vm_end)
-		return -EINVAL;
-	if (args->end <= args->vma->vm_start || args->end > args->vma->vm_end)
-		return -EINVAL;
 	if (!args->src || !args->dst)
 		return -EINVAL;
-
-	memset(args->src, 0, sizeof(*args->src) * nr_pages);
-	args->cpages = 0;
-	args->npages = 0;
-
-	migrate_vma_collect(args);
+	if (args->vma) {
+		if (is_vm_hugetlb_page(args->vma) ||
+		    (args->vma->vm_flags & VM_SPECIAL) || vma_is_dax(args->vma))
+			return -EINVAL;
+		if (args->start < args->vma->vm_start ||
+		    args->start >= args->vma->vm_end)
+			return -EINVAL;
+		if (args->end <= args->vma->vm_start ||
+		    args->end > args->vma->vm_end)
+			return -EINVAL;
+		memset(args->src, 0, sizeof(*args->src) * nr_pages);
+		args->cpages = 0;
+		args->npages = 0;
+
+		migrate_vma_collect(args);
+	}
 
 	if (args->cpages)
 		migrate_vma_unmap(args);
@@ -661,7 +661,7 @@  void migrate_vma_pages(struct migrate_vma *migrate)
 			continue;
 		}
 
-		if (!page) {
+		if (!page && migrate->vma) {
 			if (!(migrate->src[i] & MIGRATE_PFN_MIGRATE))
 				continue;
 			if (!notified) {