[Xen-changelog] [xen staging] mm: disallow MEMF_no_refcount to be passed for domain-owned allocations

[patchbot@xxxxxxx]

commit d13e07df79a1ee209dcbe02c52b59ced6210b826
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri Nov 23 12:08:09 2018 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri Nov 23 12:08:09 2018 +0100

    mm: disallow MEMF_no_refcount to be passed for domain-owned allocations
    
    When such pages get assigned to domains (and hence their ->tot_pages
    not incremented accordingly) we would otherwise also need to suppress
    decrementing the count when freeing those pages.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/common/page_alloc.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 08ee8cfbb9..4a2cbda1db 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -2303,6 +2303,11 @@ struct page_info *alloc_domheap_pages(
 
     if ( memflags & MEMF_no_owner )
         memflags |= MEMF_no_refcount;
+    else if ( (memflags & MEMF_no_refcount) && d )
+    {
+        ASSERT(!(memflags & MEMF_no_refcount));
+        return NULL;
+    }
 
     if ( dma_bitsize && ((dma_zone = bits_to_zone(dma_bitsize)) < zone_hi) )
         pg = alloc_heap_pages(dma_zone + 1, zone_hi, order, memflags, d);
--
generated by git-patchbot for /home/xen/git/xen.git#staging

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