From mboxrd@z Thu Jan 1 00:00:00 1970 From: sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org Subject: [RFC][PATCH 3/7] Add target_pid parameter to alloc_pidmap() Date: Mon, 4 May 2009 01:17:41 -0700 Message-ID: <12414250651744-git-send-email-sukadev@linux.vnet.ibm.com> References: <12414250653025-git-send-email-sukadev@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Resent-Message-ID: <20090504165845.GC31285-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> Resent-To: Containers In-Reply-To: <12414250653025-git-send-email-sukadev-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@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: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Cc: Sukadev Bhattiprolu List-Id: containers.vger.kernel.org From: Sukadev Bhattiprolu 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 fd72ad9..93406c6 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -147,12 +147,36 @@ 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 >= 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, offset, max_scan, pid, last = pid_ns->last_pid; struct pidmap *map; int rc = -EAGAIN; + if (target_pid) + return set_pidmap(pid_ns, target_pid); + pid = last + 1; if (pid >= pid_max) pid = RESERVED_PIDS; @@ -269,7 +293,7 @@ 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