From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Elder Subject: [PATCH 01/11] rbd: handle locking inside __rbd_client_find() Date: Fri, 24 Aug 2012 11:32:11 -0500 Message-ID: <5037AC8B.6070608@inktank.com> References: <5037AB20.4000103@inktank.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ob0-f174.google.com ([209.85.214.174]:58290 "EHLO mail-ob0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932586Ab2HXQcR (ORCPT ); Fri, 24 Aug 2012 12:32:17 -0400 Received: by obbuo13 with SMTP id uo13so4590607obb.19 for ; Fri, 24 Aug 2012 09:32:16 -0700 (PDT) In-Reply-To: <5037AB20.4000103@inktank.com> Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org There is only one caller of __rbd_client_find(), and it somewhat clumsily gets the appropriate lock and gets a reference to the existing ceph_client structure if it's found. Instead, have that function handle its own locking, and acquire the reference if found while it holds the lock. Drop the underscores from the name because there's no need to signify anything special about this function. Signed-off-by: Alex Elder --- drivers/block/rbd.c | 29 ++++++++++++++++------------- 1 file changed, 16 insertions(+), 13 deletions(-) diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c index 8e6e29e..81b5344 100644 --- a/drivers/block/rbd.c +++ b/drivers/block/rbd.c @@ -322,19 +322,28 @@ out_opt: } /* - * Find a ceph client with specific addr and configuration. + * Find a ceph client with specific addr and configuration. If + * found, bump its reference count. */ -static struct rbd_client *__rbd_client_find(struct ceph_options *ceph_opts) +static struct rbd_client *rbd_client_find(struct ceph_options *ceph_opts) { struct rbd_client *client_node; + bool found = false; if (ceph_opts->flags & CEPH_OPT_NOSHARE) return NULL; - list_for_each_entry(client_node, &rbd_client_list, node) - if (!ceph_compare_options(ceph_opts, client_node->client)) - return client_node; - return NULL; + spin_lock(&rbd_client_list_lock); + list_for_each_entry(client_node, &rbd_client_list, node) { + if (!ceph_compare_options(ceph_opts, client_node->client)) { + kref_get(&client_node->kref); + found = true; + break; + } + } + spin_unlock(&rbd_client_list_lock); + + return found ? client_node : NULL; } /* @@ -416,22 +425,16 @@ static struct rbd_client *rbd_get_client(const char *mon_addr, return ERR_CAST(ceph_opts); } - spin_lock(&rbd_client_list_lock); - rbdc = __rbd_client_find(ceph_opts); + rbdc = rbd_client_find(ceph_opts); if (rbdc) { /* using an existing client */ - kref_get(&rbdc->kref); - spin_unlock(&rbd_client_list_lock); - ceph_destroy_options(ceph_opts); kfree(rbd_opts); return rbdc; } - spin_unlock(&rbd_client_list_lock); rbdc = rbd_client_create(ceph_opts, rbd_opts); - if (IS_ERR(rbdc)) kfree(rbd_opts); -- 1.7.9.5