From patchwork Tue Apr 12 14:30:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Niklas Schnelle X-Patchwork-Id: 12810861 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 1A2A5C433FE for ; Tue, 12 Apr 2022 14:30:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356543AbiDLOdJ (ORCPT ); Tue, 12 Apr 2022 10:33:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355090AbiDLOdH (ORCPT ); Tue, 12 Apr 2022 10:33:07 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0B315EDD1; Tue, 12 Apr 2022 07:30:49 -0700 (PDT) Received: from pps.filterd (m0098419.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.1.2/8.16.1.2) with SMTP id 23CCpI0K024862; Tue, 12 Apr 2022 14:30:46 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding; s=pp1; bh=QnPfcT3aQm4wRRbd1y2TwgeqmbD666U2uW+Vxfg7yaQ=; b=k5HmvYUzNEKLjgpmjyAHxkR4xWbizrqwQW44riS0FXVCUVowrMMKv+KF0SHYM+D+RTXi JjS/W2lUISFjhu2QRjmSVCoQhcjFYf26A9Wt5a3jYjhLOhMQXVtSPfWtV80plLhCK2I8 pTxlWsunZ9SlRH11Mcyjj22jTxPijeTnqkSogdIpXRvg2OIOnVovyd/yvvSFkWKXIMMw ct86DxHd6VTDWQo2gvlGc59+zZUwYVzM6ae26rA2zz3KaTy7aDP20w8V5LZh3DfyULAI A1OxFIYvBngod6hPxGl/xuriDn0b24vLLEkW0osYPXNoIDtiaJ22bQP+6NW+qJqSmgA6 UQ== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 3fd9t0adfh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Apr 2022 14:30:46 +0000 Received: from m0098419.ppops.net (m0098419.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 23CDe5Mi024231; Tue, 12 Apr 2022 14:30:46 GMT Received: from ppma02fra.de.ibm.com (47.49.7a9f.ip4.static.sl-reverse.com [159.122.73.71]) by mx0b-001b2d01.pphosted.com with ESMTP id 3fd9t0adeq-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Apr 2022 14:30:46 +0000 Received: from pps.filterd (ppma02fra.de.ibm.com [127.0.0.1]) by ppma02fra.de.ibm.com (8.16.1.2/8.16.1.2) with SMTP id 23CEEVvp008989; Tue, 12 Apr 2022 14:30:43 GMT Received: from b06cxnps4075.portsmouth.uk.ibm.com (d06relay12.portsmouth.uk.ibm.com [9.149.109.197]) by ppma02fra.de.ibm.com with ESMTP id 3fb1s8m3kp-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 12 Apr 2022 14:30:43 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps4075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 23CEUea939780772 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 12 Apr 2022 14:30:40 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C2E7E52051; Tue, 12 Apr 2022 14:30:40 +0000 (GMT) Received: from tuxmaker.boeblingen.de.ibm.com (unknown [9.152.85.9]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 8BB3752065; Tue, 12 Apr 2022 14:30:40 +0000 (GMT) From: Niklas Schnelle To: Bjorn Helgaas , Jan Kiszka , Matthew Rosato , Pierre Morel Cc: linux-s390@vger.kernel.org, linux-pci@vger.kernel.org Subject: [PATCH v2 1/4] PCI: Clean up pci_scan_slot() Date: Tue, 12 Apr 2022 16:30:37 +0200 Message-Id: <20220412143040.1882096-2-schnelle@linux.ibm.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220412143040.1882096-1-schnelle@linux.ibm.com> References: <20220412143040.1882096-1-schnelle@linux.ibm.com> MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: Nq8p9b8seVNkcfbCNa8WR1XbX6X0953G X-Proofpoint-GUID: VPosIRNNQ3HJB8YY6OpN-PR4IN6ZWAoA X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-04-12_05,2022-04-12_02,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 lowpriorityscore=0 mlxlogscore=999 priorityscore=1501 adultscore=0 clxscore=1015 malwarescore=0 bulkscore=0 phishscore=0 spamscore=0 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2204120068 Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org While determining the next PCI function is factored out of pci_scan_slot() into next_fn() the former still handles the first function as a special case duplicating the code from the scan loop and splitting the condition that the first function exits from it being multifunction which is tested in next_fn(). Furthermore the non ARI branch of next_fn() mixes the case that multifunction devices may have non-contiguous function ranges and dev may thus be NULL with the multifunction requirement. It also signals that no further functions need to be scanned by returning 0 which is a valid function number. Improve upon this by moving all conditions for having to scan for more functions into next_fn() and make them obvious and commented. By changing next_fn() to return -ENODEV instead of 0 when there is no next function we can then handle the initial function inside the loop and deduplicate the shared handling. No functional change is intended. Signed-off-by: Niklas Schnelle --- drivers/pci/probe.c | 41 +++++++++++++++++++---------------------- 1 file changed, 19 insertions(+), 22 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 17a969942d37..389aa1f9cb2c 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2579,33 +2579,35 @@ struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn) } EXPORT_SYMBOL(pci_scan_single_device); -static unsigned int next_fn(struct pci_bus *bus, struct pci_dev *dev, - unsigned int fn) +static int next_fn(struct pci_bus *bus, struct pci_dev *dev, int fn) { int pos; u16 cap = 0; unsigned int next_fn; - if (pci_ari_enabled(bus)) { - if (!dev) - return 0; + if (dev && pci_ari_enabled(bus)) { pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ARI); if (!pos) - return 0; + return -ENODEV; pci_read_config_word(dev, pos + PCI_ARI_CAP, &cap); next_fn = PCI_ARI_CAP_NFN(cap); if (next_fn <= fn) - return 0; /* protect against malformed list */ + return -ENODEV; /* protect against malformed list */ return next_fn; } - /* dev may be NULL for non-contiguous multifunction devices */ - if (!dev || dev->multifunction) - return (fn + 1) % 8; - - return 0; + /* only multifunction devices may have more functions */ + if (dev && !dev->multifunction) + return -ENODEV; + /* + * A function 0 is required but multifunction devices may + * be non-contiguous so dev can be NULL otherwise. + */ + if (!fn && !dev) + return -ENODEV; + return (fn <= 6) ? fn + 1 : -ENODEV; } static int only_one_child(struct pci_bus *bus) @@ -2643,24 +2645,19 @@ static int only_one_child(struct pci_bus *bus) */ int pci_scan_slot(struct pci_bus *bus, int devfn) { - unsigned int fn, nr = 0; - struct pci_dev *dev; + int fn, nr = 0; + struct pci_dev *dev = NULL; if (only_one_child(bus) && (devfn > 0)) return 0; /* Already scanned the entire slot */ - dev = pci_scan_single_device(bus, devfn); - if (!dev) - return 0; - if (!pci_dev_is_added(dev)) - nr++; - - for (fn = next_fn(bus, dev, 0); fn > 0; fn = next_fn(bus, dev, fn)) { + for (fn = 0; fn >= 0; fn = next_fn(bus, dev, fn)) { dev = pci_scan_single_device(bus, devfn + fn); if (dev) { if (!pci_dev_is_added(dev)) nr++; - dev->multifunction = 1; + if (nr > 1) + dev->multifunction = 1; } }