From patchwork Mon Aug 16 13:02:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 498716 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04A1BC4320A for ; Mon, 16 Aug 2021 13:22:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E45CB632A9 for ; Mon, 16 Aug 2021 13:22:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239223AbhHPNWd (ORCPT ); Mon, 16 Aug 2021 09:22:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:44514 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240962AbhHPNU0 (ORCPT ); Mon, 16 Aug 2021 09:20:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id E505463305; Mon, 16 Aug 2021 13:15:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1629119755; bh=SiPgRGHbGQySDNfy3OJn4o1z2BoGp7oudsaI9vqwVuA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DwzKRXGK6+rV+kqWOoeU0wuMlpUmB+HlM8fM15RqFWmEI1/RGM+5RedlfUPrech3x 6V1wlt0sTgcWLi20pEz2kDv2l2Mlyz0b3JR1GhGkN+s+5mXuc+2ozowMxAZnOzoap0 tdE7Z8VCr/KuvyefiaZV1asLeBEpr/aXKhd2Qi+0= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jeff Layton , Ilya Dryomov Subject: [PATCH 5.13 149/151] ceph: clean up locking annotation for ceph_get_snap_realm and __lookup_snap_realm Date: Mon, 16 Aug 2021 15:02:59 +0200 Message-Id: <20210816125448.990001213@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210816125444.082226187@linuxfoundation.org> References: <20210816125444.082226187@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Jeff Layton commit df2c0cb7f8e8c83e495260ad86df8c5da947f2a7 upstream. They both say that the snap_rwsem must be held for write, but I don't see any real reason for it, and it's not currently always called that way. The lookup is just walking the rbtree, so holding it for read should be fine there. The "get" is bumping the refcount and (possibly) removing it from the empty list. I see no need to hold the snap_rwsem for write for that. Signed-off-by: Jeff Layton Reviewed-by: Ilya Dryomov Signed-off-by: Ilya Dryomov Signed-off-by: Greg Kroah-Hartman --- fs/ceph/snap.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -60,12 +60,12 @@ /* * increase ref count for the realm * - * caller must hold snap_rwsem for write. + * caller must hold snap_rwsem. */ void ceph_get_snap_realm(struct ceph_mds_client *mdsc, struct ceph_snap_realm *realm) { - lockdep_assert_held_write(&mdsc->snap_rwsem); + lockdep_assert_held(&mdsc->snap_rwsem); dout("get_realm %p %d -> %d\n", realm, atomic_read(&realm->nref), atomic_read(&realm->nref)+1); @@ -139,7 +139,7 @@ static struct ceph_snap_realm *ceph_crea /* * lookup the realm rooted at @ino. * - * caller must hold snap_rwsem for write. + * caller must hold snap_rwsem. */ static struct ceph_snap_realm *__lookup_snap_realm(struct ceph_mds_client *mdsc, u64 ino) @@ -147,7 +147,7 @@ static struct ceph_snap_realm *__lookup_ struct rb_node *n = mdsc->snap_realms.rb_node; struct ceph_snap_realm *r; - lockdep_assert_held_write(&mdsc->snap_rwsem); + lockdep_assert_held(&mdsc->snap_rwsem); while (n) { r = rb_entry(n, struct ceph_snap_realm, node);