From 2669324b81e5f67d409d3ad988da77c7c2a09045 Mon Sep 17 00:00:00 2001
From: Kefeng Wang <wangkefeng.wang@huawei.com>
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 <wangkefeng.wang@huawei.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
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 6b5f7e6e7155f..57b17978e1560 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 4f75fee497f14..cb4aa725252e8 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.
--
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