From 2669324b81e5f67d409d3ad988da77c7c2a09045 Mon Sep 17 00:00:00 2001 From: Kefeng Wang Date: Tue, 4 Jun 2024 19:48:20 +0800 Subject: [PATCH] mm: remove page_maybe_dma_pinned() After the last user of page_maybe_dma_pinned() is converted to folio_maybe_dma_pinned(), remove page_maybe_dma_pinned() and update the document and comment. [wangkefeng.wang@huawei.com: fix pin_user_pages.rst underlining] Link: https://lkml.kernel.org/r/61b256c7-4989-44ec-83db-f34a1bd4be2d@huawei.com Link: https://lkml.kernel.org/r/20240604114822.2089819-3-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Acked-by: David Hildenbrand Cc: Daniel Vetter Cc: Helge Deller Cc: Jonathan Corbet Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- Documentation/core-api/pin_user_pages.rst | 12 ++++++------ include/linux/mm.h | 9 ++------- 2 files changed, 8 insertions(+), 13 deletions(-) diff --git a/Documentation/core-api/pin_user_pages.rst b/Documentation/core-api/pin_user_pages.rst index 6b5f7e6e7155..57b17978e156 100644 --- a/Documentation/core-api/pin_user_pages.rst +++ b/Documentation/core-api/pin_user_pages.rst @@ -196,20 +196,20 @@ INCORRECT (uses FOLL_GET calls): write to the data within the pages put_page() -page_maybe_dma_pinned(): the whole point of pinning -=================================================== +folio_maybe_dma_pinned(): the whole point of pinning +==================================================== -The whole point of marking pages as "DMA-pinned" or "gup-pinned" is to be able -to query, "is this page DMA-pinned?" That allows code such as page_mkclean() +The whole point of marking folios as "DMA-pinned" or "gup-pinned" is to be able +to query, "is this folio DMA-pinned?" That allows code such as page_mkclean() (and file system writeback code in general) to make informed decisions about -what to do when a page cannot be unmapped due to such pins. +what to do when a folio cannot be unmapped due to such pins. What to do in those cases is the subject of a years-long series of discussions and debates (see the References at the end of this document). It's a TODO item here: fill in the details once that's worked out. Meanwhile, it's safe to say that having this available: :: - static inline bool page_maybe_dma_pinned(struct page *page) + static inline bool folio_maybe_dma_pinned(struct folio *folio) ...is a prerequisite to solving the long-running gup+DMA problem. diff --git a/include/linux/mm.h b/include/linux/mm.h index 4f75fee497f1..cb4aa725252e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1918,8 +1918,8 @@ static inline struct folio *pfn_folio(unsigned long pfn) * * For more information, please see Documentation/core-api/pin_user_pages.rst. * - * Return: True, if it is likely that the page has been "dma-pinned". - * False, if the page is definitely not dma-pinned. + * Return: True, if it is likely that the folio has been "dma-pinned". + * False, if the folio is definitely not dma-pinned. */ static inline bool folio_maybe_dma_pinned(struct folio *folio) { @@ -1938,11 +1938,6 @@ static inline bool folio_maybe_dma_pinned(struct folio *folio) GUP_PIN_COUNTING_BIAS; } -static inline bool page_maybe_dma_pinned(struct page *page) -{ - return folio_maybe_dma_pinned(page_folio(page)); -} - /* * This should most likely only be called during fork() to see whether we * should break the cow immediately for an anon page on the src mm.