From 5fec0719908bdabdf9d017b0f488d18019ed00f7 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Fri, 4 Feb 2022 10:32:01 -0500 Subject: [PATCH] mm/gup: Convert try_grab_page() to use a folio Hoist the folio conversion and the folio_ref_count() check to the top of the function instead of using the one buried in try_get_page(). Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: John Hubbard Reviewed-by: Christoph Hellwig --- mm/gup.c | 28 +++++++++++++--------------- 1 file changed, 13 insertions(+), 15 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index 11eba8e..81eb876 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -174,15 +174,14 @@ static void put_compound_head(struct page *page, int refs, unsigned int flags) /** * try_grab_page() - elevate a page's refcount by a flag-dependent amount + * @page: pointer to page to be grabbed + * @flags: gup flags: these are the FOLL_* flag values. * * This might not do anything at all, depending on the flags argument. * * "grab" names in this file mean, "look at flags to decide whether to use * FOLL_PIN or FOLL_GET behavior, when incrementing the page's refcount. * - * @page: pointer to page to be grabbed - * @flags: gup flags: these are the FOLL_* flag values. - * * Either FOLL_PIN or FOLL_GET (or neither) may be set, but not both at the same * time. Cases: please see the try_grab_folio() documentation, with * "refs=1". @@ -193,29 +192,28 @@ static void put_compound_head(struct page *page, int refs, unsigned int flags) */ bool __must_check try_grab_page(struct page *page, unsigned int flags) { + struct folio *folio = page_folio(page); + WARN_ON_ONCE((flags & (FOLL_GET | FOLL_PIN)) == (FOLL_GET | FOLL_PIN)); + if (WARN_ON_ONCE(folio_ref_count(folio) <= 0)) + return false; if (flags & FOLL_GET) - return try_get_page(page); + folio_ref_inc(folio); else if (flags & FOLL_PIN) { - page = compound_head(page); - - if (WARN_ON_ONCE(page_ref_count(page) <= 0)) - return false; - /* - * Similar to try_grab_compound_head(): be sure to *also* + * Similar to try_grab_folio(): be sure to *also* * increment the normal page refcount field at least once, * so that the page really is pinned. */ - if (PageHead(page)) { - page_ref_add(page, 1); - atomic_add(1, compound_pincount_ptr(page)); + if (folio_test_large(folio)) { + folio_ref_add(folio, 1); + atomic_add(1, folio_pincount_ptr(folio)); } else { - page_ref_add(page, GUP_PIN_COUNTING_BIAS); + folio_ref_add(folio, GUP_PIN_COUNTING_BIAS); } - mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_ACQUIRED, 1); + node_stat_mod_folio(folio, NR_FOLL_PIN_ACQUIRED, 1); } return true; -- 2.7.4