Commit fce70da3 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: add filemap_range_uptodate 

Move the complicated condition and the calculations out of
filemap_update_page() into its own function.

[willy@infradead.org: unlock page before dropping its refcount]
  Link: https://lkml.kernel.org/r/20210201125229.GO308988@casper.infradead.org

Link: https://lkml.kernel.org/r/20210122160140.223228-14-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarKent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 87d1d7b6

mm/filemap.c

+39 −26
Original line number Diff line number Diff line
@@ -2233,11 +2233,36 @@ static int filemap_read_page(struct file *file, struct address_space *mapping, 
	return error;

}



static bool filemap_range_uptodate(struct address_space *mapping,

		loff_t pos, struct iov_iter *iter, struct page *page)

{

	int count;



	if (PageUptodate(page))

		return true;

	/* pipes can't handle partially uptodate pages */

	if (iov_iter_is_pipe(iter))

		return false;

	if (!mapping->a_ops->is_partially_uptodate)

		return false;

	if (mapping->host->i_blkbits >= (PAGE_SHIFT + thp_order(page)))

		return false;



	count = iter->count;

	if (page_offset(page) > pos) {

		count -= page_offset(page) - pos;

		pos = 0;

	} else {

		pos -= page_offset(page);

	}



	return mapping->a_ops->is_partially_uptodate(page, pos, count);

}



static int filemap_update_page(struct kiocb *iocb,

		struct address_space *mapping, struct iov_iter *iter,

		struct page *page, loff_t pos, loff_t count)

		struct page *page)

{

	struct inode *inode = mapping->host;

	int error;



	if (!trylock_page(page)) {
@@ -2254,26 +2279,15 @@ static int filemap_update_page(struct kiocb *iocb, 


	if (!page->mapping)

		goto truncated;

	if (PageUptodate(page))

		goto uptodate;

	if (inode->i_blkbits == PAGE_SHIFT ||

			!mapping->a_ops->is_partially_uptodate)

		goto readpage;

	/* pipes can't handle partially uptodate pages */

	if (unlikely(iov_iter_is_pipe(iter)))

		goto readpage;

	if (!mapping->a_ops->is_partially_uptodate(page,

				pos & (thp_size(page) - 1), count))

		goto readpage;

uptodate:

	unlock_page(page);

	return 0;



readpage:

	if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {

		unlock_page(page);

		return -EAGAIN;

	}

	error = 0;

	if (filemap_range_uptodate(mapping, iocb->ki_pos, iter, page))

		goto unlock;



	error = -EAGAIN;

	if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ))

		goto unlock;



	error = filemap_read_page(iocb->ki_filp, mapping, page);

	if (error == AOP_TRUNCATED_PAGE)

		put_page(page);
@@ -2282,6 +2296,9 @@ static int filemap_update_page(struct kiocb *iocb, 
	unlock_page(page);

	put_page(page);

	return AOP_TRUNCATED_PAGE;

unlock:

	unlock_page(page);

	return error;

}



static int filemap_create_page(struct file *file,
@@ -2351,9 +2368,6 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
	{

		struct page *page = pvec->pages[pvec->nr - 1];

		pgoff_t pg_index = page->index;

		loff_t pg_pos = max(iocb->ki_pos,

				    (loff_t) pg_index << PAGE_SHIFT);

		loff_t pg_count = iocb->ki_pos + iter->count - pg_pos;



		if (PageReadahead(page)) {

			if (iocb->ki_flags & IOCB_NOIO) {
@@ -2370,8 +2384,7 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
			if ((iocb->ki_flags & IOCB_WAITQ) &&

			    pagevec_count(pvec) > 1)

				iocb->ki_flags |= IOCB_NOWAIT;

			err = filemap_update_page(iocb, mapping, iter, page,

					pg_pos, pg_count);

			err = filemap_update_page(iocb, mapping, iter, page);

			if (err) {

				if (err < 0)

					put_page(page);