Commit 2642fca6 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: restructure filemap_get_pages 

Remove the got_pages label, remove indentation, rename find_page to retry,
simplify error handling.

Link: https://lkml.kernel.org/r/20210122160140.223228-16-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 5963fe03

mm/filemap.c

+28 −43
Original line number Diff line number Diff line
@@ -2349,70 +2349,55 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
	struct file_ra_state *ra = &filp->f_ra;

	pgoff_t index = iocb->ki_pos >> PAGE_SHIFT;

	pgoff_t last_index;

	struct page *page;

	int err = 0;



	last_index = DIV_ROUND_UP(iocb->ki_pos + iter->count, PAGE_SIZE);

find_page:

retry:

	if (fatal_signal_pending(current))

		return -EINTR;



	filemap_get_read_batch(mapping, index, last_index, pvec);

	if (pvec->nr)

		goto got_pages;



	if (!pagevec_count(pvec)) {

		if (iocb->ki_flags & IOCB_NOIO)

			return -EAGAIN;



	page_cache_sync_readahead(mapping, ra, filp, index, last_index - index);



		page_cache_sync_readahead(mapping, ra, filp, index,

				last_index - index);

		filemap_get_read_batch(mapping, index, last_index, pvec);

	}

	if (!pagevec_count(pvec)) {

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

			return -EAGAIN;

		err = filemap_create_page(filp, mapping,

				iocb->ki_pos >> PAGE_SHIFT, pvec);

		if (err == AOP_TRUNCATED_PAGE)

			goto find_page;

			goto retry;

		return err;

	}

got_pages:

	{

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



	page = pvec->pages[pagevec_count(pvec) - 1];

	if (PageReadahead(page)) {

			err = filemap_readahead(iocb, filp, mapping, page,

					last_index);

			if (err) {

				put_page(page);

				pvec->nr--;

		err = filemap_readahead(iocb, filp, mapping, page, last_index);

		if (err)

			goto err;

	}

		}



	if (!PageUptodate(page)) {

			if ((iocb->ki_flags & IOCB_WAITQ) &&

			    pagevec_count(pvec) > 1)

		if ((iocb->ki_flags & IOCB_WAITQ) && pagevec_count(pvec) > 1)

			iocb->ki_flags |= IOCB_NOWAIT;

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

			if (err) {

				if (err < 0)

					put_page(page);

				pvec->nr--;

			}

		}

		if (err)

			goto err;

	}



	return 0;

err:

	if (likely(pvec->nr))

	if (err < 0)

		put_page(page);

	if (likely(--pvec->nr))

		return 0;

	if (err == AOP_TRUNCATED_PAGE)

		goto find_page;

	if (err)

		goto retry;

	return err;

	/*

	 * No pages and no error means we raced and should retry:

	 */

	goto find_page;

}



/**