[PATCH 1/3] pids: Make alloc_pid return error

[Pavel Emelyanov <xemul@parallels.com>]

Currently the alloc_pid just reports the pid allocation failre
and this gets reported as ENOMEM to user. With the clone-with-pid
ability the error codes set will be extended and this patch eases
this extension.

Signed-off-by: Pavel Emelyanov <xemul@parallels.com>

---
 kernel/fork.c |    5 +++--
 kernel/pid.c  |    9 ++++-----
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index 8e6b6f4..45a5f54 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1253,10 +1253,11 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 		goto bad_fork_cleanup_io;
 
 	if (pid != &init_struct_pid) {
-		retval = -ENOMEM;
 		pid = alloc_pid(p->nsproxy->pid_ns);
-		if (!pid)
+		if (IS_ERR(pid)) {
+			retval = PTR_ERR(pid);
 			goto bad_fork_cleanup_io;
+		}
 	}
 
 	p->pid = pid_nr(pid);
diff --git a/kernel/pid.c b/kernel/pid.c
index e432057..4816f43 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -214,7 +214,7 @@ static int alloc_pidmap(struct pid_namespace *pid_ns)
 		}
 		pid = mk_pid(pid_ns, map, offset);
 	}
-	return -1;
+	return -ENOMEM;
 }
 
 int next_pidmap(struct pid_namespace *pid_ns, unsigned int last)
@@ -281,7 +281,7 @@ struct pid *alloc_pid(struct pid_namespace *ns)
 {
 	struct pid *pid;
 	enum pid_type type;
-	int i, nr;
+	int i, nr = -ENOMEM;
 	struct pid_namespace *tmp;
 	struct upid *upid;
 
@@ -313,7 +313,6 @@ struct pid *alloc_pid(struct pid_namespace *ns)
 				&pid_hash[pid_hashfn(upid->nr, upid->ns)]);
 	spin_unlock_irq(&pidmap_lock);
 
-out:
 	return pid;
 
 out_free:
@@ -321,8 +320,8 @@ out_free:
 		free_pidmap(pid->numbers + i);
 
 	kmem_cache_free(ns->pid_cachep, pid);
-	pid = NULL;
-	goto out;
+out:
+	return ERR_PTR(nr);
 }
 
 struct pid *find_pid_ns(int nr, struct pid_namespace *ns)
-- 
1.5.5.6