linux-kernel - [PATCH v2 03/16] 9p: Tell the VFS that readpage was synchronous

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Date:   Fri,  9 Oct 2020 15:30:51 +0100
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     linux-fsdevel@...r.kernel.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        linux-mm@...ck.org, v9fs-developer@...ts.sourceforge.net,
        linux-kernel@...r.kernel.org, linux-afs@...ts.infradead.org,
        ceph-devel@...r.kernel.org, linux-cifs@...r.kernel.org,
        ecryptfs@...r.kernel.org, linux-um@...ts.infradead.org,
        linux-mtd@...ts.infradead.org, Richard Weinberger <richard@....at>,
        linux-xfs@...r.kernel.org,
        Dominique Martinet <asmadeus@...ewreck.org>
Subject: [PATCH v2 03/16] 9p: Tell the VFS that readpage was synchronous

The 9p readpage implementation was already synchronous, so use
AOP_UPDATED_PAGE to avoid cycling the page lock.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Acked-by: Dominique Martinet <asmadeus@...ewreck.org>
---
 fs/9p/vfs_addr.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
index cce9ace651a2..506ca0ba2ec7 100644
--- a/fs/9p/vfs_addr.c
+++ b/fs/9p/vfs_addr.c
@@ -65,7 +65,7 @@ static int v9fs_fid_readpage(void *data, struct page *page)
 	SetPageUptodate(page);
 
 	v9fs_readpage_to_fscache(inode, page);
-	retval = 0;
+	return AOP_UPDATED_PAGE;
 
 done:
 	unlock_page(page);
@@ -280,6 +280,10 @@ static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
 		goto out;
 
 	retval = v9fs_fid_readpage(v9inode->writeback_fid, page);
+	if (retval == AOP_UPDATED_PAGE) {
+		retval = 0;
+		goto out;
+	}
 	put_page(page);
 	if (!retval)
 		goto start;
-- 
2.28.0