From patchwork Mon Mar 4 06:31:38 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: NeilBrown X-Patchwork-Id: 10837339 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D7D031390 for ; Mon, 4 Mar 2019 06:33:58 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BFDA0288C9 for ; Mon, 4 Mar 2019 06:33:58 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AFE7A28915; Mon, 4 Mar 2019 06:33:58 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from pdx1-mailman02.dreamhost.com (pdx1-mailman02.dreamhost.com [64.90.62.194]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 451B6288C9 for ; Mon, 4 Mar 2019 06:33:58 +0000 (UTC) Received: from pdx1-mailman02.dreamhost.com (localhost [IPv6:::1]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id DA96B21F845; Sun, 3 Mar 2019 22:33:57 -0800 (PST) X-Original-To: lustre-devel@lists.lustre.org Delivered-To: lustre-devel-lustre.org@pdx1-mailman02.dreamhost.com Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by pdx1-mailman02.dreamhost.com (Postfix) with ESMTP id EFF7421FA8A for ; Sun, 3 Mar 2019 22:33:55 -0800 (PST) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 111D4AC9C; Mon, 4 Mar 2019 06:33:55 +0000 (UTC) From: NeilBrown To: Andreas Dilger , James Simmons , Oleg Drokin Date: Mon, 04 Mar 2019 17:31:38 +1100 Message-ID: <155168109825.31333.15239500185325332009.stgit@noble.brown> In-Reply-To: <155168107971.31333.14345309795939467246.stgit@noble.brown> References: <155168107971.31333.14345309795939467246.stgit@noble.brown> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Subject: [lustre-devel] [PATCH 05/28] lustre: obd_type: discard obd_type_lock X-BeenThere: lustre-devel@lists.lustre.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "For discussing Lustre software development." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Lustre Development List Errors-To: lustre-devel-bounces@lists.lustre.org Sender: "lustre-devel" X-Virus-Scanned: ClamAV using ClamSMTP This lock is only used to protect typ_refcnt, so change that to an atomic_t and discard the lock. The lock also covers calls to try_module_get and module_put, but this serves no purpose as it does not prevent the module from being unloaded. Finally, the return value for the call to try_module_get is ignored, which is not safe. Signed-off-by: NeilBrown --- drivers/staging/lustre/lustre/include/obd.h | 3 +- drivers/staging/lustre/lustre/mdc/mdc_request.c | 2 + drivers/staging/lustre/lustre/mgc/mgc_request.c | 2 + drivers/staging/lustre/lustre/obdclass/genops.c | 30 +++++++++----------- drivers/staging/lustre/lustre/obdclass/lu_object.c | 2 + 5 files changed, 18 insertions(+), 21 deletions(-) diff --git a/drivers/staging/lustre/lustre/include/obd.h b/drivers/staging/lustre/lustre/include/obd.h index 4c58b916e0a3..61fb8159af20 100644 --- a/drivers/staging/lustre/lustre/include/obd.h +++ b/drivers/staging/lustre/lustre/include/obd.h @@ -102,9 +102,8 @@ struct obd_type { struct obd_ops *typ_dt_ops; struct md_ops *typ_md_ops; struct dentry *typ_debugfs_entry; - int typ_refcnt; + atomic_t typ_refcnt; struct lu_device_type *typ_lu; - spinlock_t obd_type_lock; struct kobject typ_kobj; }; #define typ_name typ_kobj.name diff --git a/drivers/staging/lustre/lustre/mdc/mdc_request.c b/drivers/staging/lustre/lustre/mdc/mdc_request.c index bc764f9dd102..705a4e3b518a 100644 --- a/drivers/staging/lustre/lustre/mdc/mdc_request.c +++ b/drivers/staging/lustre/lustre/mdc/mdc_request.c @@ -2542,7 +2542,7 @@ static int mdc_init_ea_size(struct obd_export *exp, u32 easize, u32 def_easize) static int mdc_precleanup(struct obd_device *obd) { /* Failsafe, ok if racy */ - if (obd->obd_type->typ_refcnt <= 1) + if (atomic_read(&obd->obd_type->typ_refcnt) <= 1) libcfs_kkuc_group_rem(0, KUC_GRP_HSM); mdc_changelog_cdev_finish(obd); diff --git a/drivers/staging/lustre/lustre/mgc/mgc_request.c b/drivers/staging/lustre/lustre/mgc/mgc_request.c index 84ba6d0e3493..0580afa2755d 100644 --- a/drivers/staging/lustre/lustre/mgc/mgc_request.c +++ b/drivers/staging/lustre/lustre/mgc/mgc_request.c @@ -715,7 +715,7 @@ static int mgc_cleanup(struct obd_device *obd) /* COMPAT_146 - old config logs may have added profiles we don't * know about */ - if (obd->obd_type->typ_refcnt <= 1) + if (atomic_read(&obd->obd_type->typ_refcnt) <= 1) /* Only for the last mgc */ class_del_profiles(); diff --git a/drivers/staging/lustre/lustre/obdclass/genops.c b/drivers/staging/lustre/lustre/obdclass/genops.c index 74195de639e4..02d829617519 100644 --- a/drivers/staging/lustre/lustre/obdclass/genops.c +++ b/drivers/staging/lustre/lustre/obdclass/genops.c @@ -113,15 +113,17 @@ static struct obd_type *class_get_type(const char *name) } } if (type) { - spin_lock(&type->obd_type_lock); - type->typ_refcnt++; - try_module_get(type->typ_dt_ops->owner); - spin_unlock(&type->obd_type_lock); - /* class_search_type() returned a counted reference, - * but we don't need that count any more as - * we have one through typ_refcnt. - */ - kobject_put(&type->typ_kobj); + if (try_module_get(type->typ_dt_ops->owner)) { + atomic_inc(&type->typ_refcnt); + /* class_search_type() returned a counted reference, + * but we don't need that count any more as + * we have one through typ_refcnt. + */ + kobject_put(&type->typ_kobj); + } else { + kobject_put(&type->typ_kobj); + type = NULL; + } } return type; } @@ -129,10 +131,7 @@ static struct obd_type *class_get_type(const char *name) void class_put_type(struct obd_type *type) { LASSERT(type); - spin_lock(&type->obd_type_lock); - type->typ_refcnt--; - module_put(type->typ_dt_ops->owner); - spin_unlock(&type->obd_type_lock); + atomic_dec(&type->typ_refcnt); } static void simple_class_release(struct kobject *kobj) @@ -222,7 +221,6 @@ int class_register_type(struct obd_ops *dt_ops, struct md_ops *md_ops, /* md_ops is optional */ if (md_ops) *type->typ_md_ops = *md_ops; - spin_lock_init(&type->obd_type_lock); rc = kobject_add(&type->typ_kobj, &lustre_kset->kobj, "%s", name); if (rc) @@ -256,8 +254,8 @@ int class_unregister_type(const char *name) return -EINVAL; } - if (type->typ_refcnt) { - CERROR("type %s has refcount (%d)\n", name, type->typ_refcnt); + if (atomic_read(&type->typ_refcnt)) { + CERROR("type %s has refcount (%d)\n", name, atomic_read(&type->typ_refcnt)); /* This is a bad situation, let's make the best of it */ /* Remove ops, but leave the name for debugging */ kfree(type->typ_dt_ops); diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c index 9c872db21040..770cc1b9e40b 100644 --- a/drivers/staging/lustre/lustre/obdclass/lu_object.c +++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c @@ -1267,7 +1267,7 @@ void lu_stack_fini(const struct lu_env *env, struct lu_device *top) next = ldt->ldt_ops->ldto_device_free(env, scan); type = ldt->ldt_obd_type; if (type) { - type->typ_refcnt--; + atomic_dec(&type->typ_refcnt); class_put_type(type); } }