From patchwork Fri Apr 29 10:42:06 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 568527 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A7AAC433EF for ; Fri, 29 Apr 2022 10:44:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357949AbiD2Kry (ORCPT ); Fri, 29 Apr 2022 06:47:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59118 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1357971AbiD2KrX (ORCPT ); Fri, 29 Apr 2022 06:47:23 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6B700C90D6; Fri, 29 Apr 2022 03:43:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 00324B8301B; Fri, 29 Apr 2022 10:43:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 624BBC385A7; Fri, 29 Apr 2022 10:42:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1651228978; bh=VHnp0citanSQJt0S+9CGN+EiqdW5AjBPFYVoF5ezIwU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GqZuXOrNQ/0ULWBz1j3bYsu3rlYN737ay5fuYQrrfmgGs8Nv4QtJz1mCkvo+nz5JY LOstX+ZLRUfbR0UTMFbXgLxg1AqRbtdr7GYNgyNg1NGHfaCfpHVv07DRAJNv8JLyO0 536Lst10kjcsmrPaugQQSHsoKPTmIrcdiAOknDoQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , Andreas Gruenbacher , Anand Jain Subject: [PATCH 5.15 19/33] gfs2: Clean up function may_grant Date: Fri, 29 Apr 2022 12:42:06 +0200 Message-Id: <20220429104052.897466249@linuxfoundation.org> X-Mailer: git-send-email 2.36.0 In-Reply-To: <20220429104052.345760505@linuxfoundation.org> References: <20220429104052.345760505@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Andreas Gruenbacher commit 6144464937fe1e6135b13a30502a339d549bf093 upstream Pass the first current glock holder into function may_grant and deobfuscate the logic there. While at it, switch from BUG_ON to GLOCK_BUG_ON in may_grant. To make that build cleanly, de-constify the may_grant arguments. We're now using function find_first_holder in do_promote, so move the function's definition above do_promote. Signed-off-by: Andreas Gruenbacher Signed-off-by: Anand Jain Signed-off-by: Greg Kroah-Hartman --- fs/gfs2/glock.c | 119 ++++++++++++++++++++++++++++++++------------------------ 1 file changed, 69 insertions(+), 50 deletions(-) --- a/fs/gfs2/glock.c +++ b/fs/gfs2/glock.c @@ -301,46 +301,59 @@ void gfs2_glock_put(struct gfs2_glock *g } /** - * may_grant - check if its ok to grant a new lock + * may_grant - check if it's ok to grant a new lock * @gl: The glock + * @current_gh: One of the current holders of @gl * @gh: The lock request which we wish to grant * - * Returns: true if its ok to grant the lock + * With our current compatibility rules, if a glock has one or more active + * holders (HIF_HOLDER flag set), any of those holders can be passed in as + * @current_gh; they are all the same as far as compatibility with the new @gh + * goes. + * + * Returns true if it's ok to grant the lock. */ -static inline int may_grant(const struct gfs2_glock *gl, const struct gfs2_holder *gh) -{ - const struct gfs2_holder *gh_head = list_first_entry(&gl->gl_holders, const struct gfs2_holder, gh_list); +static inline bool may_grant(struct gfs2_glock *gl, + struct gfs2_holder *current_gh, + struct gfs2_holder *gh) +{ + if (current_gh) { + GLOCK_BUG_ON(gl, !test_bit(HIF_HOLDER, ¤t_gh->gh_iflags)); + + switch(current_gh->gh_state) { + case LM_ST_EXCLUSIVE: + /* + * Here we make a special exception to grant holders + * who agree to share the EX lock with other holders + * who also have the bit set. If the original holder + * has the LM_FLAG_NODE_SCOPE bit set, we grant more + * holders with the bit set. + */ + return gh->gh_state == LM_ST_EXCLUSIVE && + (current_gh->gh_flags & LM_FLAG_NODE_SCOPE) && + (gh->gh_flags & LM_FLAG_NODE_SCOPE); - if (gh != gh_head) { - /** - * Here we make a special exception to grant holders who agree - * to share the EX lock with other holders who also have the - * bit set. If the original holder has the LM_FLAG_NODE_SCOPE bit - * is set, we grant more holders with the bit set. - */ - if (gh_head->gh_state == LM_ST_EXCLUSIVE && - (gh_head->gh_flags & LM_FLAG_NODE_SCOPE) && - gh->gh_state == LM_ST_EXCLUSIVE && - (gh->gh_flags & LM_FLAG_NODE_SCOPE)) - return 1; - if ((gh->gh_state == LM_ST_EXCLUSIVE || - gh_head->gh_state == LM_ST_EXCLUSIVE)) - return 0; + case LM_ST_SHARED: + case LM_ST_DEFERRED: + return gh->gh_state == current_gh->gh_state; + + default: + return false; + } } + if (gl->gl_state == gh->gh_state) - return 1; + return true; if (gh->gh_flags & GL_EXACT) - return 0; + return false; if (gl->gl_state == LM_ST_EXCLUSIVE) { - if (gh->gh_state == LM_ST_SHARED && gh_head->gh_state == LM_ST_SHARED) - return 1; - if (gh->gh_state == LM_ST_DEFERRED && gh_head->gh_state == LM_ST_DEFERRED) - return 1; + return gh->gh_state == LM_ST_SHARED || + gh->gh_state == LM_ST_DEFERRED; } - if (gl->gl_state != LM_ST_UNLOCKED && (gh->gh_flags & LM_FLAG_ANY)) - return 1; - return 0; + if (gh->gh_flags & LM_FLAG_ANY) + return gl->gl_state != LM_ST_UNLOCKED; + return false; } static void gfs2_holder_wake(struct gfs2_holder *gh) @@ -381,6 +394,24 @@ static void do_error(struct gfs2_glock * } /** + * find_first_holder - find the first "holder" gh + * @gl: the glock + */ + +static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl) +{ + struct gfs2_holder *gh; + + if (!list_empty(&gl->gl_holders)) { + gh = list_first_entry(&gl->gl_holders, struct gfs2_holder, + gh_list); + if (test_bit(HIF_HOLDER, &gh->gh_iflags)) + return gh; + } + return NULL; +} + +/** * do_promote - promote as many requests as possible on the current queue * @gl: The glock * @@ -393,14 +424,15 @@ __releases(&gl->gl_lockref.lock) __acquires(&gl->gl_lockref.lock) { const struct gfs2_glock_operations *glops = gl->gl_ops; - struct gfs2_holder *gh, *tmp; + struct gfs2_holder *gh, *tmp, *first_gh; int ret; restart: + first_gh = find_first_holder(gl); list_for_each_entry_safe(gh, tmp, &gl->gl_holders, gh_list) { if (test_bit(HIF_HOLDER, &gh->gh_iflags)) continue; - if (may_grant(gl, gh)) { + if (may_grant(gl, first_gh, gh)) { if (gh->gh_list.prev == &gl->gl_holders && glops->go_lock) { spin_unlock(&gl->gl_lockref.lock); @@ -723,23 +755,6 @@ out: } /** - * find_first_holder - find the first "holder" gh - * @gl: the glock - */ - -static inline struct gfs2_holder *find_first_holder(const struct gfs2_glock *gl) -{ - struct gfs2_holder *gh; - - if (!list_empty(&gl->gl_holders)) { - gh = list_first_entry(&gl->gl_holders, struct gfs2_holder, gh_list); - if (test_bit(HIF_HOLDER, &gh->gh_iflags)) - return gh; - } - return NULL; -} - -/** * run_queue - do all outstanding tasks related to a glock * @gl: The glock in question * @nonblock: True if we must not block in run_queue @@ -1354,8 +1369,12 @@ __acquires(&gl->gl_lockref.lock) GLOCK_BUG_ON(gl, true); if (gh->gh_flags & (LM_FLAG_TRY | LM_FLAG_TRY_1CB)) { - if (test_bit(GLF_LOCK, &gl->gl_flags)) - try_futile = !may_grant(gl, gh); + if (test_bit(GLF_LOCK, &gl->gl_flags)) { + struct gfs2_holder *first_gh; + + first_gh = find_first_holder(gl); + try_futile = !may_grant(gl, first_gh, gh); + } if (test_bit(GLF_INVALIDATE_IN_PROGRESS, &gl->gl_flags)) goto fail; }