Commit f253e185 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

mm/filemap: change filemap_create_page calling conventions 

By moving the iocb flag checks to the caller, we can pass the file and the
page index instead of the iocb.  It never needed the iter.  By passing the
pagevec, we can return an errno (or AOP_TRUNCATED_PAGE) instead of an
ERR_PTR.

Link: https://lkml.kernel.org/r/20210122160140.223228-11-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 68430303

mm/filemap.c

+27 −26
Original line number Diff line number Diff line
@@ -2290,32 +2290,33 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp, 
	return NULL;

}



static struct page *filemap_create_page(struct kiocb *iocb,

		struct iov_iter *iter)

static int filemap_create_page(struct file *file,

		struct address_space *mapping, pgoff_t index,

		struct pagevec *pvec)

{

	struct file *filp = iocb->ki_filp;

	struct address_space *mapping = filp->f_mapping;

	pgoff_t index = iocb->ki_pos >> PAGE_SHIFT;

	struct page *page;

	int error;



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

		return ERR_PTR(-EAGAIN);



	page = page_cache_alloc(mapping);

	if (!page)

		return ERR_PTR(-ENOMEM);

		return -ENOMEM;



	error = add_to_page_cache_lru(page, mapping, index,

			mapping_gfp_constraint(mapping, GFP_KERNEL));

	if (!error)

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

	if (!error)

		return page;

	if (error == -EEXIST)

		error = AOP_TRUNCATED_PAGE;

	if (error)

		goto error;



	error = filemap_read_page(file, mapping, page);

	if (error)

		goto error;



	pagevec_add(pvec, page);

	return 0;

error:

	put_page(page);

	if (error == -EEXIST || error == AOP_TRUNCATED_PAGE)

		return NULL;

	return ERR_PTR(error);

	return error;

}



static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
@@ -2343,15 +2344,15 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter, 
	page_cache_sync_readahead(mapping, ra, filp, index, last_index - index);



	filemap_get_read_batch(mapping, index, last_index, pvec);

	if (pvec->nr)

		goto got_pages;



	pvec->pages[0] = filemap_create_page(iocb, iter);

	err = PTR_ERR_OR_ZERO(pvec->pages[0]);

	if (IS_ERR_OR_NULL(pvec->pages[0]))

		goto err;

	pvec->nr = 1;

	return 0;

	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;

		return err;

	}

got_pages:

	{

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