From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:42066 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732483AbeK3Bi1 (ORCPT ); Thu, 29 Nov 2018 20:38:27 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Matthew Wilcox Subject: [PATCH 4.19 099/110] dax: Avoid losing wakeup in dax_lock_mapping_entry Date: Thu, 29 Nov 2018 15:13:10 +0100 Message-Id: <20181129135925.248125334@linuxfoundation.org> In-Reply-To: <20181129135921.231283053@linuxfoundation.org> References: <20181129135921.231283053@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthew Wilcox commit 25bbe21bf427a81b8e3ccd480ea0e1d940256156 upstream. After calling get_unlocked_entry(), you have to call put_unlocked_entry() to avoid subsequent waiters losing wakeups. Fixes: c2a7d2a11552 ("filesystem-dax: Introduce dax_lock_mapping_entry()") Cc: stable@vger.kernel.org Signed-off-by: Matthew Wilcox Signed-off-by: Greg Kroah-Hartman --- fs/dax.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) --- a/fs/dax.c +++ b/fs/dax.c @@ -217,6 +217,9 @@ static inline void *unlock_slot(struct a return (void *)entry; } +static void put_unlocked_mapping_entry(struct address_space *mapping, + pgoff_t index, void *entry); + /* * Lookup entry in radix tree, wait for it to become unlocked if it is * exceptional entry and return it. The caller must call @@ -256,8 +259,10 @@ static void *__get_unlocked_mapping_entr revalidate = wait_fn(); finish_wait(wq, &ewait.wait); xa_lock_irq(&mapping->i_pages); - if (revalidate) + if (revalidate) { + put_unlocked_mapping_entry(mapping, index, entry); return ERR_PTR(-EAGAIN); + } } }