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 B71FDC433EF for ; Fri, 17 Jun 2022 10:09:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1381578AbiFQKJA (ORCPT ); Fri, 17 Jun 2022 06:09:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55752 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235799AbiFQKI6 (ORCPT ); Fri, 17 Jun 2022 06:08:58 -0400 Received: from mail-yw1-x1133.google.com (mail-yw1-x1133.google.com [IPv6:2607:f8b0:4864:20::1133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6BE02182A; Fri, 17 Jun 2022 03:08:57 -0700 (PDT) Received: by mail-yw1-x1133.google.com with SMTP id 00721157ae682-3176b6ed923so37502437b3.11; Fri, 17 Jun 2022 03:08:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=8ZtTCbfKlPy1sL/nTBNWOhi7Cc4DXnL97uQEVaSoU5Y=; b=Bn9B64Pt3h6XPuX2xWZhh1L40RUgLFZn8YPoo453y7DYbt3jiKhoxaPdbdQoM2OVlP qGRR8vPqBRWgs7M+UljIO+i2rZ1i3HpW+C4AcrVhmPYbsLuxo7l/VPKjIVCqSJRqLxBo QdVQGH61qRJDbo/9XXdrSkyteARSwL8wSWzAdZBUPNNKJtG6QDwoc9RpKtbXrzQQ1F/n 0WNVbXlY7jIQuhm8gAcQX9kDW83Y1z+RtOy/uWoFpWKWcEjoZfTeUtOwcTb+hBAZ+120 bN+5PjBi1XEZSDWy7N4dujgTcYlKy6Gq+wQ1GiMlrZDkz+wr40dPA9HD2RTDfNG2kMyV xZXQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=8ZtTCbfKlPy1sL/nTBNWOhi7Cc4DXnL97uQEVaSoU5Y=; b=5JSF1HCLpkqQylzXv+F4FzmmZrCBzzKkKiB52xLFqFLvkhQQ5lNdGjQ1R8HlgVBf/E /6ACMXNTzJz+x64dISuGwmd96s2yAQ5UlzqjFZIRbV2re8oLkKhNILmfhoqiQYdiWmFV E80Iz0Thb4P6J1OqUI0RtXccIefPrjROwSTxt05uUCAxXpYdJ8h3hYVC4WTPlJ+56bWr xlXMJcQl2V+zw0arUoD/Ou9XWL7yd3Ber5EJoN4EcA5MlS3pYlHhVJTNOHCDryYQL/PT HrPkUpP+Z6DOZFkbS3V0AVIX2g+F24vGapsblmOKtCrC5EUENTMZyiDsdol2NliOk0j+ dg9Q== X-Gm-Message-State: AJIora8IpAv6UGP0KjqNQiU+i1TjgaZUIDwci17HtbCyPZbqANcULMGl OD2gVAem0usCWWfYrUA5IGjSmFnkPZrKaMdnHgo= X-Google-Smtp-Source: AGRyM1uHItNie6E+DKP/KEFCrtfManttjsqKWZrVKmAP7oSq4xHHGuslFvTiGJSYcaPG3Jb3ElMPpoeai9beNh+z4Cs= X-Received: by 2002:a81:a24c:0:b0:314:4396:5aca with SMTP id z12-20020a81a24c000000b0031443965acamr10979392ywg.386.1655460536806; Fri, 17 Jun 2022 03:08:56 -0700 (PDT) MIME-Version: 1.0 References: <20220605145835.26916-1-wuchi.zero@gmail.com> In-Reply-To: <20220605145835.26916-1-wuchi.zero@gmail.com> From: chi wu Date: Fri, 17 Jun 2022 18:08:45 +0800 Message-ID: Subject: Re: [PATCH] lib/sbitmap: Fix invalid loop in __sbitmap_queue_get_batch() To: axboe@kernel.dk, mwilck@suse.com, andriy.shevchenko@linux.intel.com Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Ping.... wuchi =E4=BA=8E2022=E5=B9=B46=E6=9C=885=E6=97=A5=E5= =91=A8=E6=97=A5 22:58=E5=86=99=E9=81=93=EF=BC=9A > > 1. Getting next index before continue branch. > 2. Checking free bits when setting the target bits. Otherwise, > it may reuse the busying bits. > > Signed-off-by: wuchi > --- > lib/sbitmap.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/lib/sbitmap.c b/lib/sbitmap.c > index ae4fd4de9ebe..29eb0484215a 100644 > --- a/lib/sbitmap.c > +++ b/lib/sbitmap.c > @@ -528,7 +528,7 @@ unsigned long __sbitmap_queue_get_batch(struct sbitma= p_queue *sbq, int nr_tags, > > sbitmap_deferred_clear(map); > if (map->word =3D=3D (1UL << (map_depth - 1)) - 1) > - continue; > + goto next; > > nr =3D find_first_zero_bit(&map->word, map_depth); > if (nr + nr_tags <=3D map_depth) { > @@ -539,6 +539,8 @@ unsigned long __sbitmap_queue_get_batch(struct sbitma= p_queue *sbq, int nr_tags, > get_mask =3D ((1UL << map_tags) - 1) << nr; > do { > val =3D READ_ONCE(map->word); > + if ((val & ~get_mask) !=3D val) > + goto next; > ret =3D atomic_long_cmpxchg(ptr, val, get= _mask | val); > } while (ret !=3D val); > get_mask =3D (get_mask & ~ret) >> nr; > @@ -549,6 +551,7 @@ unsigned long __sbitmap_queue_get_batch(struct sbitma= p_queue *sbq, int nr_tags, > return get_mask; > } > } > +next: > /* Jump to next index. */ > if (++index >=3D sb->map_nr) > index =3D 0; > -- > 2.20.1 >