From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759397AbZKYS4v (ORCPT ); Wed, 25 Nov 2009 13:56:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758838AbZKYS4u (ORCPT ); Wed, 25 Nov 2009 13:56:50 -0500 Received: from e1.ny.us.ibm.com ([32.97.182.141]:52609 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758782AbZKYS4t (ORCPT ); Wed, 25 Nov 2009 13:56:49 -0500 Date: Wed, 25 Nov 2009 10:56:46 -0800 From: Sukadev Bhattiprolu To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Oren Laadan , serue@us.ibm.com, "Eric W. Biederman" , Alexey Dobriyan , Pavel Emelyanov , hpa@zytor.com, Nathan Lynch , haveblue@us.ibm.com, Matt Helsley , arnd@arndb.de, roland@redhat.com, mtk.manpages@googlemail.com, linux-api@vger.kernel.org, Containers Subject: [v13][PATCH 01/12] Factor out code to allocate pidmap page Message-ID: <20091125185646.GB30858@us.ibm.com> References: <20091125185543.GA30858@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091125185543.GA30858@us.ibm.com> X-Operating-System: Linux 2.0.32 on an i486 User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sukadev Bhattiprolu Subject: [v13][PATCH 01/12] Factor out code to allocate pidmap page To simplify alloc_pidmap(), move code to allocate a pid map page to a separate function. Changelog[v3]: - Earlier version of patchset called alloc_pidmap_page() from two places. But now its called from only one place. Even so, moving this code out into a separate function simplifies alloc_pidmap(). Changelog[v2]: - (Matt Helsley, Dave Hansen) Have alloc_pidmap_page() return -ENOMEM on error instead of -1. Signed-off-by: Sukadev Bhattiprolu Acked-by: Serge Hallyn Reviewed-by: Oren Laadan --- kernel/pid.c | 45 ++++++++++++++++++++++++++++++--------------- 1 files changed, 30 insertions(+), 15 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index d3f722d..7d4bb6e 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -122,9 +122,35 @@ static void free_pidmap(struct upid *upid) atomic_inc(&map->nr_free); } +static int alloc_pidmap_page(struct pidmap *map) +{ + void *page; + + if (likely(map->page)) + return 0; + + page = kzalloc(PAGE_SIZE, GFP_KERNEL); + + /* + * Free the page if someone raced with us installing it: + */ + spin_lock_irq(&pidmap_lock); + if (map->page) + kfree(page); + else + map->page = page; + spin_unlock_irq(&pidmap_lock); + + if (unlikely(!map->page)) + return -ENOMEM; + + return 0; +} + static int alloc_pidmap(struct pid_namespace *pid_ns) { int i, offset, max_scan, pid, last = pid_ns->last_pid; + int rc; struct pidmap *map; pid = last + 1; @@ -134,21 +160,10 @@ static int alloc_pidmap(struct pid_namespace *pid_ns) map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; max_scan = (pid_max + BITS_PER_PAGE - 1)/BITS_PER_PAGE - !offset; for (i = 0; i <= max_scan; ++i) { - if (unlikely(!map->page)) { - void *page = kzalloc(PAGE_SIZE, GFP_KERNEL); - /* - * Free the page if someone raced with us - * installing it: - */ - spin_lock_irq(&pidmap_lock); - if (map->page) - kfree(page); - else - map->page = page; - spin_unlock_irq(&pidmap_lock); - if (unlikely(!map->page)) - break; - } + rc = alloc_pidmap_page(map); + if (rc) + break; + if (likely(atomic_read(&map->nr_free))) { do { if (!test_and_set_bit(offset, map->page)) { -- 1.6.0.4