Make this function more generic by passing the file instead of the iocb.
Check in the callers whether we should call readpage or not. Also make
it return an errno / 0 / AOP_TRUNCATED_PAGE, and make calling put_page()
the caller's responsibility.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
mm/filemap.c | 89 +++++++++++++++++++++++++---------------------------
1 file changed, 42 insertions(+), 47 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index ee1255a88106f..ceb2931f5725f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2212,56 +2212,38 @@ static void filemap_get_read_batch(struct address_space *mapping,
rcu_read_unlock();
}
-static struct page *filemap_read_page(struct kiocb *iocb, struct file *filp,
- struct address_space *mapping, struct page *page)
+static int filemap_read_page(struct file *file, struct address_space *mapping,
+ struct page *page)
{
- struct file_ra_state *ra = &filp->f_ra;
int error;
- if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {
- unlock_page(page);
- put_page(page);
- return ERR_PTR(-EAGAIN);
- }
-
/*
- * A previous I/O error may have been due to temporary
- * failures, eg. multipath errors.
- * PG_error will be set again if readpage fails.
+ * A previous I/O error may have been due to temporary failures,
+ * eg. multipath errors. PG_error will be set again if readpage
+ * fails.
*/
ClearPageError(page);
/* Start the actual read. The read will unlock the page. */
- error = mapping->a_ops->readpage(filp, page);
-
- if (unlikely(error)) {
- put_page(page);
- return error != AOP_TRUNCATED_PAGE ? ERR_PTR(error) : NULL;
- }
+ error = mapping->a_ops->readpage(file, page);
+ if (error)
+ return error;
+ if (PageUptodate(page))
+ return 0;
+ error = lock_page_killable(page);
+ if (error)
+ return error;
if (!PageUptodate(page)) {
- error = lock_page_killable(page);
- if (unlikely(error)) {
- put_page(page);
- return ERR_PTR(error);
- }
- if (!PageUptodate(page)) {
- if (page->mapping == NULL) {
- /*
- * invalidate_mapping_pages got it
- */
- unlock_page(page);
- put_page(page);
- return NULL;
- }
- unlock_page(page);
- shrink_readahead_size_eio(ra);
- put_page(page);
- return ERR_PTR(-EIO);
+ if (page->mapping == NULL) {
+ /* page truncated */
+ error = AOP_TRUNCATED_PAGE;
+ } else {
+ shrink_readahead_size_eio(&file->f_ra);
+ error = -EIO;
}
- unlock_page(page);
}
-
- return page;
+ unlock_page(page);
+ return error;
}
static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
@@ -2303,7 +2285,18 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
return page;
readpage:
- return filemap_read_page(iocb, filp, mapping, page);
+ if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) {
+ unlock_page(page);
+ put_page(page);
+ return ERR_PTR(-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);
truncated:
unlock_page(page);
put_page(page);
@@ -2319,7 +2312,7 @@ static struct page *filemap_create_page(struct kiocb *iocb,
struct page *page;
int error;
- if (iocb->ki_flags & IOCB_NOIO)
+ if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ))
return ERR_PTR(-EAGAIN);
page = page_cache_alloc(mapping);
@@ -2328,12 +2321,14 @@ static struct page *filemap_create_page(struct kiocb *iocb,
error = add_to_page_cache_lru(page, mapping, index,
mapping_gfp_constraint(mapping, GFP_KERNEL));
- if (error) {
- put_page(page);
- return error != -EEXIST ? ERR_PTR(error) : NULL;
- }
-
- return filemap_read_page(iocb, filp, mapping, page);
+ if (!error)
+ error = filemap_read_page(iocb->ki_filp, mapping, page);
+ if (!error)
+ return page;
+ put_page(page);
+ if (error == -EEXIST || error == AOP_TRUNCATED_PAGE)
+ return NULL;
+ return ERR_PTR(error);
}
static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
--
2.29.2
