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mm/gup: small refactoring: simplify try_grab_page()
try_grab_page() does the same thing as try_grab_compound_head(..., refs=1, ...), just with a different API. So there is a lot of code duplication there. Change try_grab_page() to call try_grab_compound_head(), while keeping the API contract identical for callers. Also, now that try_grab_compound_head() always has a caller, remove the __maybe_unused annotation. Link: https://lkml.kernel.org/r/20210813044133.1536842-3-jhubbard@nvidia.com Signed-off-by: John Hubbard <jhubbard@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Matthew Wilcox <willy@infradead.org> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -1214,8 +1214,8 @@ static inline void get_page(struct page *page)
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}
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bool __must_check try_grab_page(struct page *page, unsigned int flags);
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__maybe_unused struct page *try_grab_compound_head(struct page *page, int refs,
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unsigned int flags);
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struct page *try_grab_compound_head(struct page *page, int refs,
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unsigned int flags);
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static inline __must_check bool try_get_page(struct page *page)
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35
mm/gup.c
35
mm/gup.c
@ -124,8 +124,8 @@ static inline struct page *try_get_compound_head(struct page *page, int refs)
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* considered failure, and furthermore, a likely bug in the caller, so a warning
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* is also emitted.
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*/
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__maybe_unused struct page *try_grab_compound_head(struct page *page,
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int refs, unsigned int flags)
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struct page *try_grab_compound_head(struct page *page,
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int refs, unsigned int flags)
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{
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if (flags & FOLL_GET)
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return try_get_compound_head(page, refs);
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@ -208,35 +208,10 @@ static void put_compound_head(struct page *page, int refs, unsigned int flags)
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*/
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bool __must_check try_grab_page(struct page *page, unsigned int flags)
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{
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WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == (FOLL_GET | FOLL_PIN));
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if (!(flags & (FOLL_GET | FOLL_PIN)))
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return true;
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if (flags & FOLL_GET)
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return try_get_page(page);
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else if (flags & FOLL_PIN) {
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int refs = 1;
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page = compound_head(page);
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if (WARN_ON_ONCE(page_ref_count(page) <= 0))
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return false;
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if (hpage_pincount_available(page))
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hpage_pincount_add(page, 1);
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else
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refs = GUP_PIN_COUNTING_BIAS;
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/*
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* Similar to try_grab_compound_head(): even if using the
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* hpage_pincount_add/_sub() routines, be sure to
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* *also* increment the normal page refcount field at least
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* once, so that the page really is pinned.
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*/
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page_ref_add(page, refs);
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mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_ACQUIRED, 1);
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}
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return true;
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return try_grab_compound_head(page, 1, flags);
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}
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/**
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