Commit b23d03ef authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

highmem: add memcpy_to_folio() and memcpy_from_folio() 

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().

[agruenba@redhat.com: use correct chunk size in memcpy()]
  Link: https://lkml.kernel.org/r/20230802144354.1023099-1-agruenba@redhat.com
Link: https://lkml.kernel.org/r/20230713035512.4139457-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20230713035512.4139457-2-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Jan Kara <jack@suse.com>
Cc: Konstantin Komarov <almaz.alexandrovich@paragon-software.com>
Cc: Pankaj Raghav <p.raghav@samsung.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Tom Rix <trix@redhat.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 6d144436

include/linux/highmem.h

+44 −0
Original line number Diff line number Diff line
@@ -439,6 +439,50 @@ static inline void memzero_page(struct page *page, size_t offset, size_t len) 
	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 {

		const 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, chunk);

		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, chunk);

		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.