Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755738AbXLETqD (ORCPT ); Wed, 5 Dec 2007 14:46:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754024AbXLETj7 (ORCPT ); Wed, 5 Dec 2007 14:39:59 -0500 Received: from mx1.redhat.com ([66.187.233.31]:34804 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754563AbXLETj5 (ORCPT ); Wed, 5 Dec 2007 14:39:57 -0500 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 From: David Howells Subject: [PATCH 16/28] CacheFiles: Permit the page lock state to be monitored [try #2] To: viro@ftp.linux.org.uk, hch@infradead.org, Trond.Myklebust@netapp.com, sds@tycho.nsa.gov, casey@schaufler-ca.com Cc: linux-kernel@vger.kernel.org, selinux@tycho.nsa.gov, linux-security-module@vger.kernel.org, dhowells@redhat.com Date: Wed, 05 Dec 2007 19:39:40 +0000 Message-ID: <20071205193939.24617.19110.stgit@warthog.procyon.org.uk> In-Reply-To: <20071205193818.24617.79771.stgit@warthog.procyon.org.uk> References: <20071205193818.24617.79771.stgit@warthog.procyon.org.uk> User-Agent: StGIT/0.13 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2172 Lines: 64 Add a function to install a monitor on the page lock waitqueue for a particular page, thus allowing the page being unlocked to be detected. This is used by CacheFiles to detect read completion on a page in the backing filesystem so that it can then copy the data to the waiting netfs page. Signed-off-by: David Howells --- include/linux/pagemap.h | 5 +++++ mm/filemap.c | 18 ++++++++++++++++++ 2 files changed, 23 insertions(+), 0 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 6a1b317..21c35e2 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -223,6 +223,11 @@ static inline void wait_on_page_fscache_write(struct page *page) extern void end_page_fscache_write(struct page *page); /* + * Add an arbitrary waiter to a page's wait queue + */ +extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter); + +/* * Fault a userspace page into pagetables. Return non-zero on a fault. * * This assumes that two userspace pages are always sufficient. That's diff --git a/mm/filemap.c b/mm/filemap.c index bea1ba6..6872d1b 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -521,6 +521,24 @@ void fastcall wait_on_page_bit(struct page *page, int bit_nr) EXPORT_SYMBOL(wait_on_page_bit); /** + * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue + * @page - Page defining the wait queue of interest + * @waiter - Waiter to add to the queue + * + * Add an arbitrary @waiter to the wait queue for the nominated @page. + */ +void add_page_wait_queue(struct page *page, wait_queue_t *waiter) +{ + wait_queue_head_t *q = page_waitqueue(page); + unsigned long flags; + + spin_lock_irqsave(&q->lock, flags); + __add_wait_queue(q, waiter); + spin_unlock_irqrestore(&q->lock, flags); +} +EXPORT_SYMBOL_GPL(add_page_wait_queue); + +/** * unlock_page - unlock a locked page * @page: the page * -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/