Commit 87d1d7b6 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: move the iocb checks into filemap_update_page 

We don't need to give up when a non-blocking request sees a !Uptodate
page.  We may be able to satisfy the read from a partially-uptodate page.

Link: https://lkml.kernel.org/r/20210122160140.223228-13-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 4612aeef

mm/filemap.c

+10 −14
Original line number Diff line number Diff line
@@ -2240,15 +2240,16 @@ static int filemap_update_page(struct kiocb *iocb, 
	struct inode *inode = mapping->host;

	int error;



	if (iocb->ki_flags & IOCB_WAITQ) {

		error = lock_page_async(page, iocb->ki_waitq);

		if (error)

			return error;

	} else {

	if (!trylock_page(page)) {

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

			return -EAGAIN;

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

			put_and_wait_on_page_locked(page, TASK_KILLABLE);

			return AOP_TRUNCATED_PAGE;

		}

		error = __lock_page_async(page, iocb->ki_waitq);

		if (error)

			return error;

	}



	if (!page->mapping)
@@ -2366,14 +2367,9 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
		}



		if (!PageUptodate(page)) {

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

			    ((iocb->ki_flags & IOCB_WAITQ) && pvec->nr > 1)) {

				put_page(page);

				pvec->nr--;

				err = -EAGAIN;

				goto err;

			}



			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);

			if (err) {