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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id E624CC05027 for ; Mon, 6 Feb 2023 17:06:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 81AC86B0072; Mon, 6 Feb 2023 12:06:49 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7CAC16B0073; Mon, 6 Feb 2023 12:06:49 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 692F76B0074; Mon, 6 Feb 2023 12:06:49 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 5AA336B0072 for ; Mon, 6 Feb 2023 12:06:49 -0500 (EST) Received: from smtpin26.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 302D91408FD for ; Mon, 6 Feb 2023 17:06:49 +0000 (UTC) X-FDA: 80437496538.26.7DB6C18 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by imf14.hostedemail.com (Postfix) with ESMTP id 396AD10001F for ; Mon, 6 Feb 2023 17:06:43 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=none; spf=pass (imf14.hostedemail.com: domain of jonathan.cameron@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=jonathan.cameron@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1675703205; a=rsa-sha256; cv=none; b=nHBee/3T+aTJKc+8qbwe5FTrn6Lkcx1v4U1q1eylsJlcZO9X3/d6dSKnNZzJE8Y9cGInFs tLafF3EVZnOtAjn79CEcUpwjALXt2nQQmxumGFPbjUnfMvnoZh7PmNc0fAzd/the3WhM1l +xL4uXrspgzTPhH1PEO48GvkSfrhPWI= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=none; spf=pass (imf14.hostedemail.com: domain of jonathan.cameron@huawei.com designates 185.176.79.56 as permitted sender) smtp.mailfrom=jonathan.cameron@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1675703205; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dWwJmTr+t9C0uHT7HOm7xLNMM6HfCiLO7sG+IEl0xEE=; b=eSdaJCtjmM6QrxTmPU9JsAHSLjc7pMBMSy62MXfQW2jijYpHASgALA6vmRxE5m1ksrtW0x CoCZIjp+aOVn1d4UqGUzVu9Tfg+MmrEAF2Vz92vNiJEZvzw8R27F6i+bF9tpuAqgWM3nEC iVSmU3DrEdJt4D+HkAHpOBn11P4Bllw= Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4P9Xh02LSGz6J9yW; Tue, 7 Feb 2023 01:05:20 +0800 (CST) Received: from localhost (10.81.207.58) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.17; Mon, 6 Feb 2023 17:06:38 +0000 Date: Mon, 6 Feb 2023 17:06:36 +0000 From: Jonathan Cameron To: Dan Williams CC: , , , Subject: Re: [PATCH 06/18] cxl/region: Refactor attach_target() for autodiscovery Message-ID: <20230206170636.0000739e@Huawei.com> In-Reply-To: <167564538227.847146.16305045998592488364.stgit@dwillia2-xfh.jf.intel.com> References: <167564534874.847146.5222419648551436750.stgit@dwillia2-xfh.jf.intel.com> <167564538227.847146.16305045998592488364.stgit@dwillia2-xfh.jf.intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.81.207.58] X-ClientProxiedBy: lhrpeml100002.china.huawei.com (7.191.160.241) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected X-Rspam-User: X-Rspamd-Queue-Id: 396AD10001F X-Rspamd-Server: rspam01 X-Stat-Signature: 9n5oi44row7p6zczred55ub4y9wogtsk X-HE-Tag: 1675703203-540611 X-HE-Meta: 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 EE93Cl21 19cPX/WTlP0DTsphs5HKHTE1xA7alHz4VbHIrXg3q4qZeBlAYjql0+q4YlVP4I1r4zL6XKVrXhb8QRvNCDOqXXYuHO4tp9C8SwZz7Tu5yAacD9RzybwFKUA7oUZ9O0D6GbmAmdYL4NSl4vLfpZqckMd8aCWheXOL03nN5FJvT0BPqYBZR85x7Btyw37dXonVZeetG4HpMcofhDHYvdsD9rzSalhuVvooKFbd3PBHfDowGdhr4EoaaFvABPtTv7b4n506zkw53OYh/4zgQZSgdB6t7Tr55aAPPmAmbPFsgDf1gn/t8dX4WG2x/ew== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Sun, 05 Feb 2023 17:03:02 -0800 Dan Williams wrote: > Region autodiscovery is the process of kernel creating 'struct > cxl_region' object to represent active CXL memory ranges it finds > already active in hardware when the driver loads. Typically this happens > when platform firmware establishes CXL memory regions and then publishes > them in the memory map. However, this can also happen in the case of > kexec-reboot after the kernel has created regions. > > In the autodiscovery case the region creation process starts with a > known endpoint decoder. Refactor attach_target() into a helper that is > suitable to be called from either sysfs, for runtime region creation, or > from cxl_port_probe() after it has enumerated all endpoint decoders. > > The cxl_port_probe() context is an async device-core probing context, so > it is not appropriate to allow SIGTERM to interrupt the assembly > process. Refactor attach_target() to take @cxled and @state as arguments > where @state indicates whether waiting from the region rwsem is > interruptible or not. As below, I'd have broken this change out as a follow up patch - that way reviewer could check for strict noop refactor, then look in ioslation at that case. I don't care that much though as second patch would only have about 4 lines of diff. Reviewed-by: Jonathan Cameron > > No behavior change is intended. > > Signed-off-by: Dan Williams > --- > drivers/cxl/core/region.c | 47 +++++++++++++++++++++++++++------------------ > 1 file changed, 28 insertions(+), 19 deletions(-) > > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c > index 8dea49c021b8..97eafdd75675 100644 > --- a/drivers/cxl/core/region.c > +++ b/drivers/cxl/core/region.c > @@ -1418,31 +1418,25 @@ void cxl_decoder_kill_region(struct cxl_endpoint_decoder *cxled) > up_write(&cxl_region_rwsem); > } > > -static int attach_target(struct cxl_region *cxlr, const char *decoder, int pos) > +static int attach_target(struct cxl_region *cxlr, > + struct cxl_endpoint_decoder *cxled, int pos, > + unsigned int state) > { > - struct device *dev; > - int rc; > - > - dev = bus_find_device_by_name(&cxl_bus_type, NULL, decoder); > - if (!dev) > - return -ENODEV; > - > - if (!is_endpoint_decoder(dev)) { > - put_device(dev); > - return -EINVAL; > - } > + int rc = 0; > > - rc = down_write_killable(&cxl_region_rwsem); > + if (state == TASK_INTERRUPTIBLE) > + rc = down_write_killable(&cxl_region_rwsem); > + else > + down_write(&cxl_region_rwsem); I'd be tempted to do this in two hops for patch readability. First make the code reorg then follow up with this bit before the use of it in the next patch. > if (rc) > - goto out; > + return rc; > + > down_read(&cxl_dpa_rwsem); > - rc = cxl_region_attach(cxlr, to_cxl_endpoint_decoder(dev), pos); > + rc = cxl_region_attach(cxlr, cxled, pos); > if (rc == 0) > set_bit(CXL_REGION_F_INCOHERENT, &cxlr->flags); > up_read(&cxl_dpa_rwsem); > up_write(&cxl_region_rwsem); > -out: > - put_device(dev); > return rc; > } > > @@ -1480,8 +1474,23 @@ static size_t store_targetN(struct cxl_region *cxlr, const char *buf, int pos, > > if (sysfs_streq(buf, "\n")) > rc = detach_target(cxlr, pos); > - else > - rc = attach_target(cxlr, buf, pos); > + else { > + struct device *dev; > + > + dev = bus_find_device_by_name(&cxl_bus_type, NULL, buf); > + if (!dev) > + return -ENODEV; > + > + if (!is_endpoint_decoder(dev)) { > + rc = -EINVAL; > + goto out; > + } > + > + rc = attach_target(cxlr, to_cxl_endpoint_decoder(dev), pos, > + TASK_INTERRUPTIBLE); > +out: > + put_device(dev); > + } > > if (rc < 0) > return rc; > >