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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2DB33ECE561 for ; Mon, 24 Sep 2018 10:54:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5E5B2086B for ; Mon, 24 Sep 2018 10:54:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D5E5B2086B Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728578AbeIXQzf (ORCPT ); Mon, 24 Sep 2018 12:55:35 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:60460 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726167AbeIXQzf (ORCPT ); Mon, 24 Sep 2018 12:55:35 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 107E880D; Mon, 24 Sep 2018 03:54:06 -0700 (PDT) Received: from [10.4.13.23] (en101.Emea.Arm.com [10.4.13.23]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C6D143F5B3; Mon, 24 Sep 2018 03:54:03 -0700 (PDT) Subject: Re: [PATCH 02/10] irqchip/gic-v3-its: Consolidate LPI_PENDBASE_SZ usage To: Julien Thierry , Marc Zyngier , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Cc: Ard Biesheuvel , Jeremy Linton , Jeffrey Hugo , Thomas Gleixner , Jason Cooper References: <20180921195954.21574-1-marc.zyngier@arm.com> <20180921195954.21574-3-marc.zyngier@arm.com> From: Suzuki K Poulose Message-ID: Date: Mon, 24 Sep 2018 11:54:02 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 24/09/18 11:50, Julien Thierry wrote: > Hi, > > On 24/09/18 11:33, Suzuki K Poulose wrote: >> Hi Marc, >> >> On 21/09/18 20:59, Marc Zyngier wrote: >>> LPI_PENDING_SZ is always used in conjunction with a max(). Let's >>> factor this in the definition of the macro, and simplify the rest >>> of the code. >>> >>> Signed-off-by: Marc Zyngier >>> --- >>>   drivers/irqchip/irq-gic-v3-its.c | 12 ++++-------- >>>   1 file changed, 4 insertions(+), 8 deletions(-) >>> >>> diff --git a/drivers/irqchip/irq-gic-v3-its.c >>> b/drivers/irqchip/irq-gic-v3-its.c >>> index c2df341ff6fa..ed6aab11e019 100644 >>> --- a/drivers/irqchip/irq-gic-v3-its.c >>> +++ b/drivers/irqchip/irq-gic-v3-its.c >>> @@ -62,7 +62,7 @@ static u32 lpi_id_bits; >>>    */ >>>   #define LPI_NRBITS        lpi_id_bits >>>   #define LPI_PROPBASE_SZ        ALIGN(BIT(LPI_NRBITS), SZ_64K) >>> -#define LPI_PENDBASE_SZ        ALIGN(BIT(LPI_NRBITS) / 8, SZ_64K) >>> +#define LPI_PENDBASE_SZ        max_t(u32, SZ_64K, >>> ALIGN(BIT(LPI_NRBITS) / 8, SZ_64K)) >> >> minor nit: The ALIGN() already aligns the given value up to the required >> alignment. So, if the LPI_NRBITS is guaranteed to be non-zero, >> we could simply drop the max_t(). >> > > Hmmm, Doesn't ALIGN only aligns down? So if "BIT(LPI_NR_BITS) / 8 < > SZ_64K" (i.e. LPI_NRBITS < 20) The ALIGN(..., SZ_64K) would give 0. Isn't it the ALIGN_DOWN(), which aligns it down ? Following the kernel definitions : linux/kernel.h -> uapi/linux/kernel.h ALIGN(x,a) => __ALIGN_KERNEL(x, a) \ => __ALIGN_KERNEL_MASK(x, (a -1) \ => (((x + (a - 1)) & ~ (a - 1)) Cheers Suzuki > > Thanks, > >> Rest looks good to me. >> >> Suzuki >> >>>   #define LPI_PROP_DEFAULT_PRIO    0xa0 >>> @@ -1924,12 +1924,9 @@ static int its_alloc_collections(struct >>> its_node *its) >>>   static struct page *its_allocate_pending_table(gfp_t gfp_flags) >>>   { >>>       struct page *pend_page; >>> -    /* >>> -     * The pending pages have to be at least 64kB aligned, >>> -     * hence the 'max(LPI_PENDBASE_SZ, SZ_64K)' below. >>> -     */ >>> + >>>       pend_page = alloc_pages(gfp_flags | __GFP_ZERO, >>> -                get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K))); >>> +                get_order(LPI_PENDBASE_SZ)); >>>       if (!pend_page) >>>           return NULL; >>> @@ -1941,8 +1938,7 @@ static struct page >>> *its_allocate_pending_table(gfp_t gfp_flags) >>>   static void its_free_pending_table(struct page *pt) >>>   { >>> -    free_pages((unsigned long)page_address(pt), >>> -           get_order(max_t(u32, LPI_PENDBASE_SZ, SZ_64K))); >>> +    free_pages((unsigned long)page_address(pt), >>> get_order(LPI_PENDBASE_SZ)); >>>   } >>>   static void its_cpu_init_lpis(void) >>> >