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author | 2021-12-10 15:09:21 -0500 | |
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committer | 2022-01-16 19:52:13 -0500 | |
commit | 3fe7fa5843d204e235d92902190fecb972a3f9cc (patch) | |
tree | 92ae8b9afc4ee5f2f7f54d86bab9312ebcb28ef6 /include/linux/mm.h | |
parent | pagevec: Initialise folio_batch->percpu_pvec_drained (diff) | |
download | linux-3fe7fa5843d204e235d92902190fecb972a3f9cc.tar.gz linux-3fe7fa5843d204e235d92902190fecb972a3f9cc.tar.bz2 linux-3fe7fa5843d204e235d92902190fecb972a3f9cc.zip |
mm: Add folio_put_refs()
This is like folio_put(), but puts N references at once instead of
just one. It's like put_page_refs(), but does one atomic operation
instead of two, and is available to more than just gup.c.
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>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r-- | include/linux/mm.h | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index c768a7c81b0b..cb98f75b245e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1244,6 +1244,26 @@ static inline void folio_put(struct folio *folio) __put_page(&folio->page); } +/** + * folio_put_refs - Reduce the reference count on a folio. + * @folio: The folio. + * @refs: The amount to subtract from the folio's reference count. + * + * If the folio's reference count reaches zero, the memory will be + * released back to the page allocator and may be used by another + * allocation immediately. Do not access the memory or the struct folio + * after calling folio_put_refs() unless you can be sure that these weren't + * the last references. + * + * Context: May be called in process or interrupt context, but not in NMI + * context. May be called while holding a spinlock. + */ +static inline void folio_put_refs(struct folio *folio, int refs) +{ + if (folio_ref_sub_and_test(folio, refs)) + __put_page(&folio->page); +} + static inline void put_page(struct page *page) { struct folio *folio = page_folio(page); |