1 files changed, 23 insertions, 53 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index 389a20eec9b8..f62b589cbfe4 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1373,14 +1373,6 @@ static int __wait_on_page_locked_async(struct page *page,
 	return ret;
 }
 
-static int wait_on_page_locked_async(struct page *page,
-				     struct wait_page_queue *wait)
-{
-	if (!PageLocked(page))
-		return 0;
-	return __wait_on_page_locked_async(compound_head(page), wait, false);
-}
-
 /**
  * put_and_wait_on_page_locked - Drop a reference and wait for it to be unlocked
  * @page: The page to wait for.
@@ -2286,64 +2278,42 @@ static struct page *filemap_update_page(struct kiocb *iocb, struct file *filp,
 	struct inode *inode = mapping->host;
 	int error;
 
-	/*
-	 * See comment in do_read_cache_page on why
-	 * wait_on_page_locked is used to avoid unnecessarily
-	 * serialisations and why it's safe.
-	 */
 	if (iocb->ki_flags & IOCB_WAITQ) {
-		error = wait_on_page_locked_async(page,
-						iocb->ki_waitq);
+		error = lock_page_async(page, iocb->ki_waitq);
+		if (error) {
+			put_page(page);
+			return ERR_PTR(error);
+		}
 	} else {
-		error = wait_on_page_locked_killable(page);
-	}
-	if (unlikely(error)) {
-		put_page(page);
-		return ERR_PTR(error);
+		if (!trylock_page(page)) {
+			put_and_wait_on_page_locked(page, TASK_KILLABLE);
+			return NULL;
+		}
 	}
-	if (PageUptodate(page))
-		return page;
 
+	if (!page->mapping)
+		goto truncated;
+	if (PageUptodate(page))
+		goto uptodate;
 	if (inode->i_blkbits == PAGE_SHIFT ||
 			!mapping->a_ops->is_partially_uptodate)
-		goto page_not_up_to_date;
+		goto readpage;
 	/* pipes can't handle partially uptodate pages */
 	if (unlikely(iov_iter_is_pipe(iter)))
-		goto page_not_up_to_date;
-	if (!trylock_page(page))
-		goto page_not_up_to_date;
-	/* Did it get truncated before we got the lock? */
-	if (!page->mapping)
-		goto page_not_up_to_date_locked;
+		goto readpage;
 	if (!mapping->a_ops->is_partially_uptodate(page,
-				pos & ~PAGE_MASK, count))
-		goto page_not_up_to_date_locked;
+				pos & (thp_size(page) - 1), count))
+		goto readpage;
+uptodate:
 	unlock_page(page);
 	return page;
 
-page_not_up_to_date:
-	/* Get exclusive access to the page ... */
-	error = lock_page_for_iocb(iocb, page);
-	if (unlikely(error)) {
-		put_page(page);
-		return ERR_PTR(error);
-	}
-
-page_not_up_to_date_locked:
-	/* Did it get truncated before we got the lock? */
-	if (!page->mapping) {
-		unlock_page(page);
-		put_page(page);
-		return NULL;
-	}
-
-	/* Did somebody else fill it already? */
-	if (PageUptodate(page)) {
-		unlock_page(page);
-		return page;
-	}
-
+readpage:
 	return filemap_read_page(iocb, filp, mapping, page);
+truncated:
+	unlock_page(page);
+	put_page(page);
+	return NULL;
 }
 
 static struct page *filemap_create_page(struct kiocb *iocb,