From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sukadev Bhattiprolu Subject: [RFC][v8][PATCH 2/10]: Have alloc_pidmap() return actual error code Date: Mon, 12 Oct 2009 21:50:17 -0700 Message-ID: <20091013045017.GB28435@us.ibm.com> References: <20091013044925.GA28181@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: <20091013044925.GA28181-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: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: randy.dunlap-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, arnd-r2nGTMty4D4@public.gmane.org, Containers , Nathan Lynch , Louis.Rilling-aw0BnHfMbSpBDgjK7y7TUQ@public.gmane.org, "Eric W. Biederman" , kosaki.motohiro-+CUm20s59erQFUHtdCDX3A@public.gmane.org, hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org, mingo-X9Un+BFzKDI@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, Alexey Dobriyan , roland-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Pavel Emelyanov List-Id: linux-api@vger.kernel.org Subject: [RFC][v8][PATCH 2/10]: Have alloc_pidmap() return actual error code alloc_pidmap() can fail either because all pid numbers are in use or because memory allocation failed. With support for setting a specific pid number, alloc_pidmap() would also fail if either the given pid number is invalid or in use. Rather than have callers assume -ENOMEM, have alloc_pidmap() return the actual error. Signed-off-by: Sukadev Bhattiprolu Acked-by: Serge Hallyn Reviewed-by: Oren Laadan --- kernel/fork.c | 5 +++-- kernel/pid.c | 14 +++++++++----- 2 files changed, 12 insertions(+), 7 deletions(-) Index: linux-2.6/kernel/fork.c =================================================================== --- linux-2.6.orig/kernel/fork.c 2009-09-09 19:06:21.000000000 -0700 +++ linux-2.6/kernel/fork.c 2009-09-09 19:06:46.000000000 -0700 @@ -1110,10 +1110,11 @@ static struct task_struct *copy_process( 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; + } if (clone_flags & CLONE_NEWPID) { retval = pid_ns_prepare_proc(p->nsproxy->pid_ns); Index: linux-2.6/kernel/pid.c =================================================================== --- linux-2.6.orig/kernel/pid.c 2009-09-09 19:06:25.000000000 -0700 +++ linux-2.6/kernel/pid.c 2009-09-09 19:06:46.000000000 -0700 @@ -150,7 +150,7 @@ static int alloc_pidmap_page(struct pidm static int alloc_pidmap(struct pid_namespace *pid_ns) { int i, offset, max_scan, pid, last = pid_ns->last_pid; - int rc; + int rc = -EAGAIN; struct pidmap *map; pid = last + 1; @@ -189,12 +189,14 @@ static int alloc_pidmap(struct pid_names } else { map = &pid_ns->pidmap[0]; offset = RESERVED_PIDS; - if (unlikely(last == offset)) + if (unlikely(last == offset)) { + rc = -EAGAIN; break; + } } pid = mk_pid(pid_ns, map, offset); } - return -1; + return rc; } int next_pidmap(struct pid_namespace *pid_ns, int last) @@ -263,8 +265,10 @@ struct pid *alloc_pid(struct pid_namespa struct upid *upid; pid = kmem_cache_alloc(ns->pid_cachep, GFP_KERNEL); - if (!pid) + if (!pid) { + pid = ERR_PTR(-ENOMEM); goto out; + } tmp = ns; for (i = ns->level; i >= 0; i--) { @@ -299,7 +303,7 @@ out_free: free_pidmap(pid->numbers + i); kmem_cache_free(ns->pid_cachep, pid); - pid = NULL; + pid = ERR_PTR(nr); goto out; }