Commit 69bbb87b authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

shmem: convert shmem_write_end() to use a folio 

Use a folio internally to shmem_write_end() which saves a number of calls
to compound_head() and lets us get rid of the custom code to zero out the
rest of a THP and supports folios of arbitrary size.

Link: https://lkml.kernel.org/r/20230112131031.1209553-1-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarWilliam Kucharski <william.kucharski@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent a6fddef4

mm/shmem.c

+10 −20
Original line number Diff line number Diff line
@@ -2578,33 +2578,23 @@ shmem_write_end(struct file *file, struct address_space *mapping, 
			loff_t pos, unsigned len, unsigned copied,

			struct page *page, void *fsdata)

{

	struct folio *folio = page_folio(page);

	struct inode *inode = mapping->host;



	if (pos + copied > inode->i_size)

		i_size_write(inode, pos + copied);



	if (!PageUptodate(page)) {

		struct page *head = compound_head(page);

		if (PageTransCompound(page)) {

			int i;



			for (i = 0; i < HPAGE_PMD_NR; i++) {

				if (head + i == page)

					continue;

				clear_highpage(head + i);

				flush_dcache_page(head + i);

			}

		}

		if (copied < PAGE_SIZE) {

			unsigned from = pos & (PAGE_SIZE - 1);

			zero_user_segments(page, 0, from,

					from + copied, PAGE_SIZE);

	if (!folio_test_uptodate(folio)) {

		if (copied < folio_size(folio)) {

			size_t from = offset_in_folio(folio, pos);

			folio_zero_segments(folio, 0, from,

					from + copied, folio_size(folio));

		}

		SetPageUptodate(head);

		folio_mark_uptodate(folio);

	}

	set_page_dirty(page);

	unlock_page(page);

	put_page(page);

	folio_mark_dirty(folio);

	folio_unlock(folio);

	folio_put(folio);



	return copied;

}