From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sukadev Bhattiprolu Subject: [RFC][PATCH 3/7][v2] Add target_pid parameter to alloc_pidmap() Date: Wed, 27 May 2009 21:38:34 -0700 Message-ID: <20090528043834.GC16522@us.ibm.com> References: <20090528043748.GA16522@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20090528043748.GA16522-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Oren Laadan Cc: Containers , "David C. Hansen" List-Id: containers.vger.kernel.org >From a1fdec1036a952359d02a7c667d126bd2fff6804 Mon Sep 17 00:00:00 2001 From: Sukadev Bhattiprolu Date: Mon, 4 May 2009 01:17:41 -0700 Subject: [RFC][PATCH 3/7][v2] Add target_pid parameter to alloc_pidmap() With support for setting a specific pid number for a process, alloc_pidmap() will need a paramter a 'target_pid' parameter. Changelog[v2]: - (Serge Hallyn) Check for 'pid < 0' in set_pidmap().(Code actually checks for 'pid <= 0' for completeness). Signed-off-by: Sukadev Bhattiprolu --- kernel/pid.c | 28 ++++++++++++++++++++++++++-- 1 files changed, 26 insertions(+), 2 deletions(-) diff --git a/kernel/pid.c b/kernel/pid.c index b2d6a19..b44dd21 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -147,11 +147,35 @@ static int alloc_pidmap_page(struct pidmap *map) return 0; } -static int alloc_pidmap(struct pid_namespace *pid_ns) +static int set_pidmap(struct pid_namespace *pid_ns, int pid) +{ + int offset; + struct pidmap *map; + + if (pid <= 0 || pid >= pid_max) + return -EINVAL; + + offset = pid & BITS_PER_PAGE_MASK; + map = &pid_ns->pidmap[pid/BITS_PER_PAGE]; + + if (alloc_pidmap_page(map)) + return -ENOMEM; + + if (test_and_set_bit(offset, map->page)) + return -EBUSY; + + atomic_dec(&map->nr_free); + return pid; +} + +static int alloc_pidmap(struct pid_namespace *pid_ns, int target_pid) { int i, rc, offset, max_scan, pid, last = pid_ns->last_pid; struct pidmap *map; + if (target_pid) + return set_pidmap(pid_ns, target_pid); + pid = last + 1; if (pid >= pid_max) pid = RESERVED_PIDS; @@ -270,7 +294,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) tmp = ns; for (i = ns->level; i >= 0; i--) { - nr = alloc_pidmap(tmp); + nr = alloc_pidmap(tmp, 0); if (nr < 0) goto out_free; -- 1.5.2.5