From mboxrd@z Thu Jan 1 00:00:00 1970 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 24E3BC4332F for ; Wed, 28 Dec 2022 10:18:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230154AbiL1KSQ (ORCPT ); Wed, 28 Dec 2022 05:18:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34994 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229989AbiL1KSP (ORCPT ); Wed, 28 Dec 2022 05:18:15 -0500 Received: from msg-1.mailo.com (msg-1.mailo.com [213.182.54.11]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 313001008; Wed, 28 Dec 2022 02:18:14 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=mailo.com; s=mailo; t=1672222686; bh=M/WpsSu89bWYdIXZA73WGR0a3a/iHvVIZdh2l2pVFIg=; h=X-EA-Auth:Date:From:To:Cc:Subject:Message-ID:References: MIME-Version:Content-Type:In-Reply-To; b=Zxs1Q9MeWF3wD/lCgXD0ZMQ6u7Erl39DodEwA0IDf7KzdRyVWn+gQED2DGaqnIPRN aYc9Qq2vPjFRuzWHDgeymXTXaZ5gKVQbzoQw7a3bAq8M7IPxJzxfLGlMgdivtHOXs5 tIyjblRpfPbsAdBRD3Z2hMDazJklm+0XPMARWh88= Received: by b-5.in.mailobj.net [192.168.90.15] with ESMTP via ip-206.mailobj.net [213.182.55.206] Wed, 28 Dec 2022 11:18:06 +0100 (CET) X-EA-Auth: dPbPgiwgZLmW7MKplEAc6RJ8/u5RW1fPFZoo2AN4ClZKHOvnd6UM2pew44/bNN5mn3iEjXNblGrAUsdLggKS0JU290FOiGGY Date: Wed, 28 Dec 2022 15:48:01 +0530 From: Deepak R Varma To: Hannes Reinecke , "James E.J. Bottomley" , "Martin K. Petersen" , linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Saurabh Singh Sengar , Praveen Kumar , Deepak R Varma Subject: Re: [PATCH] scsi: libfc: Use refcount_* APIs for reference count management Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Tue, Dec 20, 2022 at 10:00:45AM +0530, Deepak R Varma wrote: > The atomic_t API based object reference counter management is prone to > counter value overflows, object use-after-free issues and to return > puzzling values. The improved refcount_t APIs are designed to address > these known issues with atomic_t reference counter management. This > white paper [1] has detailed reasons for moving from atomic_t to > refcount_t APIs. Hence replace the atomic_* based implementation by its > refcount_* based equivalent. > The issue is identified using atomic_as_refcounter.cocci Coccinelle > semantic patch script. > > [1] https://arxiv.org/pdf/1710.06175.pdf > > Signed-off-by: Deepak R Varma Hello, May I please request a review and feedback on this patch proposal? Thank you, ./drv > --- > Note: The proposal is compile tested only. > > drivers/scsi/libfc/fc_exch.c | 10 +++++----- > include/scsi/libfc.h | 2 +- > 2 files changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c > index 1d91c457527f..1c49fddb65e3 100644 > --- a/drivers/scsi/libfc/fc_exch.c > +++ b/drivers/scsi/libfc/fc_exch.c > @@ -246,7 +246,7 @@ static const char *fc_exch_rctl_name(unsigned int op) > */ > static inline void fc_exch_hold(struct fc_exch *ep) > { > - atomic_inc(&ep->ex_refcnt); > + refcount_inc(&ep->ex_refcnt); > } > > /** > @@ -312,7 +312,7 @@ static void fc_exch_release(struct fc_exch *ep) > { > struct fc_exch_mgr *mp; > > - if (atomic_dec_and_test(&ep->ex_refcnt)) { > + if (refcount_dec_and_test(&ep->ex_refcnt)) { > mp = ep->em; > if (ep->destructor) > ep->destructor(&ep->seq, ep->arg); > @@ -329,7 +329,7 @@ static inline void fc_exch_timer_cancel(struct fc_exch *ep) > { > if (cancel_delayed_work(&ep->timeout_work)) { > FC_EXCH_DBG(ep, "Exchange timer canceled\n"); > - atomic_dec(&ep->ex_refcnt); /* drop hold for timer */ > + refcount_dec(&ep->ex_refcnt); /* drop hold for timer */ > } > } > > @@ -1897,7 +1897,7 @@ static void fc_exch_reset(struct fc_exch *ep) > ep->state |= FC_EX_RST_CLEANUP; > fc_exch_timer_cancel(ep); > if (ep->esb_stat & ESB_ST_REC_QUAL) > - atomic_dec(&ep->ex_refcnt); /* drop hold for rec_qual */ > + refcount_dec(&ep->ex_refcnt); /* drop hold for rec_qual */ > ep->esb_stat &= ~ESB_ST_REC_QUAL; > sp = &ep->seq; > rc = fc_exch_done_locked(ep); > @@ -2332,7 +2332,7 @@ static void fc_exch_els_rrq(struct fc_frame *fp) > */ > if (ep->esb_stat & ESB_ST_REC_QUAL) { > ep->esb_stat &= ~ESB_ST_REC_QUAL; > - atomic_dec(&ep->ex_refcnt); /* drop hold for rec qual */ > + refcount_dec(&ep->ex_refcnt); /* drop hold for rec qual */ > } > if (ep->esb_stat & ESB_ST_COMPLETE) > fc_exch_timer_cancel(ep); > diff --git a/include/scsi/libfc.h b/include/scsi/libfc.h > index 6e29e1719db1..ce65149b300c 100644 > --- a/include/scsi/libfc.h > +++ b/include/scsi/libfc.h > @@ -432,7 +432,7 @@ struct fc_seq { > */ > struct fc_exch { > spinlock_t ex_lock; > - atomic_t ex_refcnt; > + refcount_t ex_refcnt; > enum fc_class class; > struct fc_exch_mgr *em; > struct fc_exch_pool *pool; > -- > 2.34.1 >