[v5,10/18] mm/filemap: Change filemap_create_page calling conventions
diff mbox series

Message ID 20210122160140.223228-11-willy@infradead.org
State In Next
Commit 561d1fa36181f295066a4950d221677d1691198a
Headers show
Series
  • Refactor generic_file_buffered_read
Related show

Commit Message

Matthew Wilcox Jan. 22, 2021, 4:01 p.m. UTC
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.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Kent Overstreet <kent.overstreet@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 mm/filemap.c | 53 ++++++++++++++++++++++++++--------------------------
 1 file changed, 27 insertions(+), 26 deletions(-)

Patch
diff mbox series

diff --git a/mm/filemap.c b/mm/filemap.c
index ceb2931f5725f..3e0790626addf 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2303,32 +2303,33 @@  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;
+			mapping_gfp_constraint(mapping, GFP_KERNEL));
+	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,
@@ -2356,15 +2357,15 @@  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];