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.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
mm/filemap.c | 24 ++++++++++--------------
1 file changed, 10 insertions(+), 14 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index adac12ed48415..141d5917770d6 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2230,15 +2230,16 @@ 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 (!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)
@@ -2356,14 +2357,9 @@ 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) {
--
2.29.2
