From patchwork Fri Feb 28 23:29:16 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 11413499 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 C873417E0 for ; Fri, 28 Feb 2020 23:30:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A822C2469C for ; Fri, 28 Feb 2020 23:30:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ryqr5p9u" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726658AbgB1XaJ (ORCPT ); Fri, 28 Feb 2020 18:30:09 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:59738 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726765AbgB1XaI (ORCPT ); Fri, 28 Feb 2020 18:30:08 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1582932607; 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=dNMWdKtvi6Hy1HcK6nwSHcXHEGZv8eiC4BgPrfgPvCs=; b=Ryqr5p9uZoH92hBrbKtW67JcKrAfVp0iNzAz9vBwzM+KO2B5Vs1ySwQJNYmmwEtG0NfPqO wBUs6Onh4Hk9rPuLdpWaNnOEtHO83lLTwYwlZImB4yMxKvEsuX7Z0uRY3MmeyONOId6BvG LzgsXlXk8PHvHODET3vH1RPVTJYLTFU= 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-223-AAw9EoVnPTiiQu9DPPeiHA-1; Fri, 28 Feb 2020 18:30:03 -0500 X-MC-Unique: AAw9EoVnPTiiQu9DPPeiHA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 69C5E800D5F; Fri, 28 Feb 2020 23:30:01 +0000 (UTC) Received: from localhost (ovpn-8-18.pek2.redhat.com [10.72.8.18]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8B8CE101D491; Fri, 28 Feb 2020 23:30:00 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org, James Bottomley , linux-scsi@vger.kernel.org, "Martin K . Petersen" Cc: Ming Lei , Omar Sandoval , Sathya Prakash , Chaitra P B , Suganath Prabu Subramani , Kashyap Desai , Sumit Saxena , Shivasharan S , "Ewan D . Milne" , Hannes Reinecke , Bart Van Assche Subject: [PATCH V2 06/10] sbitmap: add helper of sbitmap_calculate_shift Date: Sat, 29 Feb 2020 07:29:16 +0800 Message-Id: <20200228232920.20960-7-ming.lei@redhat.com> In-Reply-To: <20200228232920.20960-1-ming.lei@redhat.com> References: <20200228232920.20960-1-ming.lei@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@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: Sathya Prakash Cc: Chaitra P B Cc: Suganath Prabu Subramani Cc: Kashyap Desai Cc: Sumit Saxena Cc: Shivasharan S Cc: Ewan D. Milne Cc: Hannes Reinecke Cc: Bart Van Assche Signed-off-by: Ming Lei --- 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 254475865b3d..bb88a3643d64 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;