mm/migrate: add stable check in migrate_vma_insert_page()

migrate_vma_insert_page() closely follows the code in:
  __handle_mm_fault()
    handle_pte_fault()
      do_anonymous_page()

Add a call to check_stable_address_space() after locking the page table
entry before inserting a ZONE_DEVICE private zero page mapping similar
to page faulting a new anonymous page.

Link: http://lkml.kernel.org/r/20200107211208.24595-4-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Bharata B Rao <bharata@linux.ibm.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Chris Down <chris@chrisdown.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index 0144e13..edf42ed 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -48,6 +48,7 @@
 #include <linux/page_owner.h>
 #include <linux/sched/mm.h>
 #include <linux/ptrace.h>
+#include <linux/oom.h>
 
 #include <asm/tlbflush.h>
 
@@ -2695,6 +2696,14 @@ int migrate_vma_setup(struct migrate_vma *args)
 }
 EXPORT_SYMBOL(migrate_vma_setup);
 
+/*
+ * This code closely matches the code in:
+ *   __handle_mm_fault()
+ *     handle_pte_fault()
+ *       do_anonymous_page()
+ * to map in an anonymous zero page but the struct page will be a ZONE_DEVICE
+ * private page.
+ */
 static void migrate_vma_insert_page(struct migrate_vma *migrate,
                                    unsigned long addr,
                                    struct page *page,
@@ -2775,6 +2784,9 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
 
        ptep = pte_offset_map_lock(mm, pmdp, addr, &ptl);
 
+       if (check_stable_address_space(mm))
+               goto unlock_abort;
+
        if (pte_present(*ptep)) {
                unsigned long pfn = pte_pfn(*ptep);