The patch titled
Subject: highmem: add memcpy_to_folio() and memcpy_from_folio()
has been added to the -mm mm-unstable branch. Its filename is
highmem-add-memcpy_to_folio-and-memcpy_from_folio.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/highmem-add-memcpy_to_folio-and-memcpy_from_folio.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: highmem: add memcpy_to_folio() and memcpy_from_folio()
Date: Thu, 13 Jul 2023 04:55:06 +0100
Patch series "More filesystem folio conversions for 6.6".
Remove the only spots in affs which actually use a struct page; there
are a few places where one is mentioned, but it's part of the interface.
The rest of this is removing the remaining calls to set_bh_page(),
and then removing the function before any new users show up.
This patch (of 7):
These are the folio equivalent of memcpy_to_page() and memcpy_from_page().
Link: https://lkml.kernel.org/r/20230713035512.4139457-1-willy@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20230713035512.4139457-2-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: Jan Kara <jack@xxxxxxxx>
Cc: Konstantin Komarov <almaz.alexandrovich@xxxxxxxxxxxxxxxxxxxx>
Cc: Pankaj Raghav <p.raghav@xxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Nathan Chancellor <nathan@xxxxxxxxxx>
Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx>
Cc: Tom Rix <trix@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem.h | 44 ++++++++++++++++++++++++++++++++++++++
1 file changed, 44 insertions(+)
--- a/include/linux/highmem.h~highmem-add-memcpy_to_folio-and-memcpy_from_folio
+++ a/include/linux/highmem.h
@@ -439,6 +439,50 @@ static inline void memzero_page(struct p
kunmap_local(addr);
}
+static inline void memcpy_from_folio(char *to, struct folio *folio,
+ size_t offset, size_t len)
+{
+ VM_BUG_ON(offset + len > folio_size(folio));
+
+ do {
+ char *from = kmap_local_folio(folio, offset);
+ size_t chunk = len;
+
+ if (folio_test_highmem(folio) &&
+ (chunk > (PAGE_SIZE - offset_in_page(offset))))
+ chunk = PAGE_SIZE - offset_in_page(offset);
+ memcpy(to, from, len);
+ kunmap_local(from);
+
+ from += chunk;
+ offset += chunk;
+ len -= chunk;
+ } while (len > 0);
+}
+
+static inline void memcpy_to_folio(struct folio *folio, size_t offset,
+ const char *from, size_t len)
+{
+ VM_BUG_ON(offset + len > folio_size(folio));
+
+ do {
+ char *to = kmap_local_folio(folio, offset);
+ size_t chunk = len;
+
+ if (folio_test_highmem(folio) &&
+ (chunk > (PAGE_SIZE - offset_in_page(offset))))
+ chunk = PAGE_SIZE - offset_in_page(offset);
+ memcpy(to, from, len);
+ kunmap_local(to);
+
+ from += chunk;
+ offset += chunk;
+ len -= chunk;
+ } while (len > 0);
+
+ flush_dcache_folio(folio);
+}
+
/**
* memcpy_from_file_folio - Copy some bytes from a file folio.
* @to: The destination buffer.
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
rmap-pass-the-folio-to-__page_check_anon_rmap.patch
highmem-add-memcpy_to_folio-and-memcpy_from_folio.patch
affs-convert-affs_symlink_read_folio-to-use-the-folio.patch
affs-convert-data-read-and-write-to-use-folios.patch
migrate-use-folio_set_bh-instead-of-set_bh_page.patch
ntfs3-convert-ntfs_get_block_vbo-to-use-a-folio.patch
jbd2-use-a-folio-in-jbd2_journal_write_metadata_buffer.patch
buffer-remove-set_bh_page.patch
