Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932279AbdCFPWw (ORCPT ); Mon, 6 Mar 2017 10:22:52 -0500 Received: from casper.infradead.org ([85.118.1.10]:50274 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753644AbdCFPWP (ORCPT ); Mon, 6 Mar 2017 10:22:15 -0500 Date: Mon, 6 Mar 2017 15:20:49 +0000 (GMT) From: James Simmons To: simran singhal cc: oleg.drokin@intel.com, andreas.dilger@intel.com, gregkh@linuxfoundation.org, lustre-devel@lists.lustre.org, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org, outreachy-kernel@googlegroups.com Subject: Re: [PATCH 5/5] staging: lustre: osc_page.c: Use list_for_each_entry_safe In-Reply-To: <1488733610-22289-6-git-send-email-singhalsimran0@gmail.com> Message-ID: References: <1488733610-22289-1-git-send-email-singhalsimran0@gmail.com> <1488733610-22289-6-git-send-email-singhalsimran0@gmail.com> User-Agent: Alpine 2.20 (LFD 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170306_152049_429723_B17CCE3D X-CRM114-Status: GOOD ( 16.92 ) X-Spam-Score: -0.6 (/) X-Spam-Report: SpamAssassin version 3.4.1 on casper.infradead.org summary: Content analysis details: (-0.6 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 NO_RELAYS Informational: message was not relayed via SMTP 1.3 TRACKER_ID BODY: Incorporates a tracking ID number -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3083 Lines: 101 > Doubly linked lists which are iterated using list_empty > and list_entry macros have been replaced with list_for_each_entry_safe > macro. > This makes the iteration simpler and more readable. > > This patch replaces the while loop containing list_empty and list_entry > with list_for_each_entry_safe. > > This was done with Coccinelle. > > @@ > expression E1; > identifier I1, I2; > type T; > iterator name list_for_each_entry_safe; > @@ > > T *I1; > + T *tmp; > ... > - while (list_empty(&E1) == 0) > + list_for_each_entry_safe (I1, tmp, &E1, I2) > { > ...when != T *I1; > - I1 = list_entry(E1.next, T, I2); > ... > } > > Signed-off-by: simran singhal NAK!!!!!! This change was reverted in commit cd15dd6ef4ea11df87f717b8b1b83aaa738ec8af Doing these while (list_empty(..)) to list_for_entry... are not simple changes and have broken things in lustre before. Unless you really understand the state machine of the lustre code I don't recommend these kinds of change for lustre. > --- > drivers/staging/lustre/lustre/osc/osc_page.c | 11 ++++------- > 1 file changed, 4 insertions(+), 7 deletions(-) > > diff --git a/drivers/staging/lustre/lustre/osc/osc_page.c b/drivers/staging/lustre/lustre/osc/osc_page.c > index ed8a0dc..e8b974f 100644 > --- a/drivers/staging/lustre/lustre/osc/osc_page.c > +++ b/drivers/staging/lustre/lustre/osc/osc_page.c > @@ -542,6 +542,7 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli, > struct cl_object *clobj = NULL; > struct cl_page **pvec; > struct osc_page *opg; > + struct osc_page *tmp; > int maxscan = 0; > long count = 0; > int index = 0; > @@ -572,7 +573,7 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli, > if (force) > cli->cl_lru_reclaim++; > maxscan = min(target << 1, atomic_long_read(&cli->cl_lru_in_list)); > - while (!list_empty(&cli->cl_lru_list)) { > + list_for_each_entry_safe(opg, tmp, &cli->cl_lru_list, ops_lru) { > struct cl_page *page; > bool will_free = false; > > @@ -582,8 +583,6 @@ long osc_lru_shrink(const struct lu_env *env, struct client_obd *cli, > if (--maxscan < 0) > break; > > - opg = list_entry(cli->cl_lru_list.next, struct osc_page, > - ops_lru); > page = opg->ops_cl.cpl_page; > if (lru_page_busy(cli, page)) { > list_move_tail(&opg->ops_lru, &cli->cl_lru_list); > @@ -1043,6 +1042,7 @@ unsigned long osc_cache_shrink_scan(struct shrinker *sk, > { > struct client_obd *stop_anchor = NULL; > struct client_obd *cli; > + struct client_obd *tmp; > struct lu_env *env; > long shrank = 0; > u16 refcheck; > @@ -1059,10 +1059,7 @@ unsigned long osc_cache_shrink_scan(struct shrinker *sk, > return SHRINK_STOP; > > spin_lock(&osc_shrink_lock); > - while (!list_empty(&osc_shrink_list)) { > - cli = list_entry(osc_shrink_list.next, struct client_obd, > - cl_shrink_list); > - > + list_for_each_entry_safe(cli, tmp, &osc_shrink_list, cl_shrink_list) { > if (!stop_anchor) > stop_anchor = cli; > else if (cli == stop_anchor) > -- > 2.7.4 > >