Re: [PATCH v3 13/14] mm/gup: grab head page refcount once for group of subpages
From: Matthew Wilcox <willy@infradead.org>
Date: 2021-08-25 19:16:30
Also in:
linux-mm, nvdimm
On Wed, Aug 25, 2021 at 08:10:39PM +0100, Joao Martins wrote:
quoted hunk ↗ jump to hunk
@@ -2273,8 +2273,7 @@ static int __gup_device_huge(unsigned long pfn, unsigned long addr, refs = record_subpages(page, addr, next, pages + *nr); SetPageReferenced(head); - pinned_head = try_grab_compound_head(head, refs, flags); - if (unlikely(!pinned_head)) { + if (unlikely(!try_grab_compound_head(head, refs, flags))) { if (PageCompound(head))
BTW, you can just check PageHead(head). We know it can't be PageTail ...