From patchwork Wed Sep 23 01:33:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 11793711 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C3CD3139F for ; Wed, 23 Sep 2020 01:34:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A81A92371F for ; Wed, 23 Sep 2020 01:34:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="MG2mf4dh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727043AbgIWBee (ORCPT ); Tue, 22 Sep 2020 21:34:34 -0400 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:21884 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726839AbgIWBec (ORCPT ); Tue, 22 Sep 2020 21:34:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600824871; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7E479vugKkICWhfNi6eJTCfhRRdyHoPaXeFzeZMqNeg=; b=MG2mf4dhifVxka4axm9oRrLMAmPBn4Cp1VhFATbTnNBqxF5+NYQCt3kZRPu/DJnlYgFwkg hRD+UGjQQ+RFIS54aOiv9ofEdtRZIFXxogOM+gnAduDSY3Z14nyFi9QkgB+YsO6KKm/Jil chdNiJXYNi5vFxkFMERWaJzoPGLv/u0= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-538-8zjJ9EQHO_mwMQuXTPBlTA-1; Tue, 22 Sep 2020 21:34:29 -0400 X-MC-Unique: 8zjJ9EQHO_mwMQuXTPBlTA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 97C131007468; Wed, 23 Sep 2020 01:34:27 +0000 (UTC) Received: from localhost (ovpn-12-168.pek2.redhat.com [10.72.12.168]) by smtp.corp.redhat.com (Postfix) with ESMTP id D017A19D6C; Wed, 23 Sep 2020 01:34:26 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, "Martin K . Petersen" , linux-scsi@vger.kernel.org Cc: Ming Lei , Omar Sandoval , Kashyap Desai , Sumanesh Samanta , "Ewan D . Milne" , Hannes Reinecke Subject: [PATCH V3 for 5.11 06/12] sbitmap: add helper of sbitmap_calculate_shift Date: Wed, 23 Sep 2020 09:33:33 +0800 Message-Id: <20200923013339.1621784-7-ming.lei@redhat.com> In-Reply-To: <20200923013339.1621784-1-ming.lei@redhat.com> References: <20200923013339.1621784-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Move code for calculating default shift into one public helper, which can be used for SCSI to calculate shift. Cc: Omar Sandoval Cc: Kashyap Desai Cc: Sumanesh Samanta Cc: Ewan D. Milne Cc: Hannes Reinecke Signed-off-by: Ming Lei Reviewed-by: Hannes Reinecke --- include/linux/sbitmap.h | 18 ++++++++++++++++++ lib/sbitmap.c | 16 +++------------- 2 files changed, 21 insertions(+), 13 deletions(-) diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h index 34343ce3ef6c..2a40364d6d00 100644 --- a/include/linux/sbitmap.h +++ b/include/linux/sbitmap.h @@ -337,6 +337,24 @@ static inline int sbitmap_test_bit(struct sbitmap *sb, unsigned int bitnr) return test_bit(SB_NR_TO_BIT(sb, bitnr), __sbitmap_word(sb, bitnr)); } +static inline int sbitmap_calculate_shift(unsigned int depth) +{ + int shift = ilog2(BITS_PER_LONG); + + /* + * If the bitmap is small, shrink the number of bits per word so + * we spread over a few cachelines, at least. If less than 4 + * bits, just forget about it, it's not going to work optimally + * anyway. + */ + if (depth >= 4) { + while ((4U << shift) > depth) + shift--; + } + + return shift; +} + /** * sbitmap_show() - Dump &struct sbitmap information to a &struct seq_file. * @sb: Bitmap to show. diff --git a/lib/sbitmap.c b/lib/sbitmap.c index ab217bf5d619..a428d26aa529 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -96,19 +96,9 @@ int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, unsigned int bits_per_word; unsigned int i; - if (shift < 0) { - shift = ilog2(BITS_PER_LONG); - /* - * If the bitmap is small, shrink the number of bits per word so - * we spread over a few cachelines, at least. If less than 4 - * bits, just forget about it, it's not going to work optimally - * anyway. - */ - if (depth >= 4) { - while ((4U << shift) > depth) - shift--; - } - } + if (shift < 0) + shift = sbitmap_calculate_shift(depth); + bits_per_word = 1U << shift; if (bits_per_word > BITS_PER_LONG) return -EINVAL;