Commit 4612aeef authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: convert filemap_update_page to return an errno 

Use AOP_TRUNCATED_PAGE to indicate that no error occurred, but the page we
looked up is no longer valid.  In this case, the reference to the page
will have been removed; if we hit any other error, the caller will release
the reference.

Link: https://lkml.kernel.org/r/20210122160140.223228-12-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 f253e185

mm/filemap.c

+17 −21
Original line number Diff line number Diff line
@@ -2233,24 +2233,21 @@ static int filemap_read_page(struct file *file, struct address_space *mapping, 
	return error;

}



static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,

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

		loff_t 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 address_space *mapping = filp->f_mapping;

	struct inode *inode = mapping->host;

	int error;



	if (iocb->ki_flags & IOCB_WAITQ) {

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

		if (error) {

			put_page(page);

			return ERR_PTR(error);

		}

		if (error)

			return error;

	} else {

		if (!trylock_page(page)) {

			put_and_wait_on_page_locked(page, TASK_KILLABLE);

			return NULL;

			return AOP_TRUNCATED_PAGE;

		}

	}
@@ -2269,25 +2266,21 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp, 
		goto readpage;

uptodate:

	unlock_page(page);

	return page;

	return 0;



readpage:

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

		unlock_page(page);

		put_page(page);

		return ERR_PTR(-EAGAIN);

		return -EAGAIN;

	}

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

	if (!error)

		return page;

	put_page(page);

	if (error == AOP_TRUNCATED_PAGE)

		return NULL;

	return ERR_PTR(error);

		put_page(page);

	return error;

truncated:

	unlock_page(page);

	put_page(page);

	return NULL;

	return AOP_TRUNCATED_PAGE;

}



static int filemap_create_page(struct file *file,
@@ -2381,11 +2374,12 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
				goto err;

			}



			page = filemap_update_page(iocb, filp, iter, page,

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

					pg_pos, pg_count);

			if (IS_ERR_OR_NULL(page)) {

			if (err) {

				if (err < 0)

					put_page(page);

				pvec->nr--;

				err = PTR_ERR_OR_ZERO(page);

			}

		}

	}
@@ -2393,6 +2387,8 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
err:

	if (likely(pvec->nr))

		return 0;

	if (err == AOP_TRUNCATED_PAGE)

		goto find_page;

	if (err)

		return err;

	/*