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mm/gup: Add gup_put_folio()

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Convert put_compound_head() to gup_put_folio() and hpage_pincount_sub()
to folio_pincount_sub().  This removes the last call to put_page_refs(),
so delete it.  Add a temporary put_compound_head() wrapper which will
be deleted by the end of this series.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-12-10 15:39:04 -05:00
parent 40fcc7fc2c
commit d8ddc099c6
1 changed files with 12 additions and 26 deletions
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38
mm/gup.c
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@ -29,23 +29,6 @@ struct follow_page_context {
unsigned int page_mask;
};
/* Equivalent to calling put_page() @refs times. */
static void put_page_refs(struct page *page, int refs)
{
#ifdef CONFIG_DEBUG_VM
if (VM_WARN_ON_ONCE_PAGE(page_ref_count(page) < refs, page))
return;
#endif
/*
* Calling put_page() for each ref is unnecessarily slow. Only the last
* ref needs a put_page().
*/
if (refs > 1)
page_ref_sub(page, refs - 1);
put_page(page);
}
/*
* Return the folio with ref appropriately incremented,
* or NULL if that failed.
@ -156,20 +139,23 @@ struct page *try_grab_compound_head(struct page *page,
return &try_grab_folio(page, refs, flags)->page;
}
static void put_compound_head(struct page *page, int refs, unsigned int flags)
static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)
{
VM_BUG_ON_PAGE(PageTail(page), page);
if (flags & FOLL_PIN) {
mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED,
refs);
if (PageHead(page))
atomic_sub(refs, compound_pincount_ptr(page));
node_stat_mod_folio(folio, NR_FOLL_PIN_RELEASED, refs);
if (folio_test_large(folio))
atomic_sub(refs, folio_pincount_ptr(folio));
else
refs *= GUP_PIN_COUNTING_BIAS;
}
put_page_refs(page, refs);
folio_put_refs(folio, refs);
}
static void put_compound_head(struct page *page, int refs, unsigned int flags)
{
VM_BUG_ON_PAGE(PageTail(page), page);
gup_put_folio((struct folio *)page, refs, flags);
}
/**
@ -230,7 +216,7 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags)
*/
void unpin_user_page(struct page *page)
{
put_compound_head(compound_head(page), 1, FOLL_PIN);
gup_put_folio(page_folio(page), 1, FOLL_PIN);
}
EXPORT_SYMBOL(unpin_user_page);