From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758895Ab3BGQO0 (ORCPT ); Thu, 7 Feb 2013 11:14:26 -0500 Received: from mail-da0-f48.google.com ([209.85.210.48]:56900 "EHLO mail-da0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756212Ab3BGQOL (ORCPT ); Thu, 7 Feb 2013 11:14:11 -0500 Date: Thu, 7 Feb 2013 08:14:04 -0800 From: Tejun Heo To: Sedat Dilek Cc: Stephen Rothwell , linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Al Viro , "Eric W. Biederman" , Andrew Morton Subject: [PATCH v2] ipc: convert to idr_alloc() Message-ID: <20130207161404.GK2875@htj.dyndns.org> References: <87ip644bqh.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Convert to the much saner new idr interface. The new interface doesn't directly translate to the way idr_pre_get() was used around ipc_addid() as preloading disables preemption. From my cursory reading, it seems like we should be able to do all allocation from ipc_addid(), so I moved it there. Can you please check whether this would be okay? If this is wrong and ipc_addid() should be allowed to be called from non-sleepable context, I'd suggest allocating id itself in the outer functions and later install the pointer using idr_replace(). Only compile tested. v2: The v1 conversion of ipcget_public() was incorrect. As idr_pre_get() returns 0 for -ENOMEM failure, @err should have been initialized to 1 not 0. As the function doesn't do preloading itself anymore, there's no point in the error handling path. Simply remove the -ENOMEM path. Signed-off-by: Tejun Heo Reported-by: Sedat Dilek Cc: Stanislav Kinsbursky Cc: "Eric W. Biederman" Cc: James Morris --- Yeah, I messed up the ipcget_public() conversion. Can you please test this one? Thanks. ipc/util.c | 30 +++++++++--------------------- 1 file changed, 9 insertions(+), 21 deletions(-) --- a/ipc/util.c +++ b/ipc/util.c @@ -252,7 +252,7 @@ int ipc_addid(struct ipc_ids* ids, struc { kuid_t euid; kgid_t egid; - int id, err; + int id; int next_id = ids->next_id; if (size > IPCMNI) @@ -261,17 +261,21 @@ int ipc_addid(struct ipc_ids* ids, struc if (ids->in_use >= size) return -ENOSPC; + idr_preload(GFP_KERNEL); + spin_lock_init(&new->lock); new->deleted = 0; rcu_read_lock(); spin_lock(&new->lock); - err = idr_get_new_above(&ids->ipcs_idr, new, - (next_id < 0) ? 0 : ipcid_to_idx(next_id), &id); - if (err) { + id = idr_alloc(&ids->ipcs_idr, new, + (next_id < 0) ? 0 : ipcid_to_idx(next_id), 0, + GFP_NOWAIT); + idr_preload_end(); + if (id < 0) { spin_unlock(&new->lock); rcu_read_unlock(); - return err; + return id; } ids->in_use++; @@ -307,19 +311,10 @@ static int ipcget_new(struct ipc_namespa struct ipc_ops *ops, struct ipc_params *params) { int err; -retry: - err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); - - if (!err) - return -ENOMEM; down_write(&ids->rw_mutex); err = ops->getnew(ns, params); up_write(&ids->rw_mutex); - - if (err == -EAGAIN) - goto retry; - return err; } @@ -376,8 +371,6 @@ static int ipcget_public(struct ipc_name struct kern_ipc_perm *ipcp; int flg = params->flg; int err; -retry: - err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); /* * Take the lock as a writer since we are potentially going to add @@ -389,8 +382,6 @@ retry: /* key not used */ if (!(flg & IPC_CREAT)) err = -ENOENT; - else if (!err) - err = -ENOMEM; else err = ops->getnew(ns, params); } else { @@ -413,9 +404,6 @@ retry: } up_write(&ids->rw_mutex); - if (err == -EAGAIN) - goto retry; - return err; }