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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B159C433EF for ; Mon, 9 May 2022 21:25:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229912AbiEIV3V (ORCPT ); Mon, 9 May 2022 17:29:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35744 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229599AbiEIV3U (ORCPT ); Mon, 9 May 2022 17:29:20 -0400 Received: from mga17.intel.com (mga17.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B97C72C2571; Mon, 9 May 2022 14:25:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652131524; x=1683667524; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=w9/+znMpjVvEE7LipRzImJB90PLvzBYflKc/N0o5Bbw=; b=Il0iF2KPsWmdjr1+UqM8VO3/YixxuDDIJXhqFSyYlGIMAjYOPVOSflTJ fXYYjRqQ+tm1tm82lImNztIrF8kPlT1vghGTrpVDtStRhp7Ur0IBnfEbi OkLN3A7V7UjUc0+JPpoTiW2x8BXIiOaFj1YAzt+JDvIXKO7CdX3k+uTMj fYYwZ2kYFyo/KspvbUWM0LDJvKDHZlIcVmSBs57rHMrqO2qmdxRIEndcg AHuH80OW11zeceWij5vFreXNlWweAN63oNIgjWoBY3vPD56foHvgY3Et1 Bm8iTi6Jx2byeieByfQLeRSJrquwziQeybxjGjobMBwCBjmgWoZkSIPEb g==; X-IronPort-AV: E=McAfee;i="6400,9594,10342"; a="249708360" X-IronPort-AV: E=Sophos;i="5.91,212,1647327600"; d="scan'208";a="249708360" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 May 2022 14:25:24 -0700 X-IronPort-AV: E=Sophos;i="5.91,212,1647327600"; d="scan'208";a="551468941" Received: from sganapa1-mobl1.amr.corp.intel.com (HELO localhost) ([10.212.98.230]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 09 May 2022 14:25:23 -0700 Date: Mon, 9 May 2022 14:25:23 -0700 From: Ira Weiny To: Jonathan Cameron Cc: Dan Williams , Bjorn Helgaas , Alison Schofield , Vishal Verma , Ben Widawsky , linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH V8 06/10] cxl/pci: Find the DOE mailbox which supports CDAT Message-ID: References: <20220414203237.2198665-1-ira.weiny@intel.com> <20220414203237.2198665-7-ira.weiny@intel.com> <20220427184956.00004507@Huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220427184956.00004507@Huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Wed, Apr 27, 2022 at 06:49:56PM +0100, Jonathan Cameron wrote: > On Thu, 14 Apr 2022 13:32:33 -0700 > ira.weiny@intel.com wrote: > > > From: Ira Weiny > > > > Each CXL device may have multiple DOE mailbox capabilities and each > > mailbox may support multiple protocols. > > > > Search the DOE auxiliary devices for one which supports the CDAT > > protocol. Cache that device to be used for future queries. > > > > Signed-off-by: Ira Weiny > > One question inline. With that addressed (or convincing argument why not) > the rest looks good. > > Reviewed-by: Jonathan Cameron Thanks! > > > > > --- > > Changes from V7 > > Minor code clean ups > > > > Changes from V6 > > Adjust for aux devices being a CXL only concept > > Update commit msg. > > Ensure devices iterated by auxiliary_find_device() are checked > > to be DOE devices prior to checking for the CDAT > > protocol > > From Ben > > Ensure reference from auxiliary_find_device() is dropped > > --- > > drivers/cxl/cxl.h | 2 ++ > > drivers/cxl/cxlmem.h | 2 ++ > > drivers/cxl/pci.c | 76 +++++++++++++++++++++++++++++++++++++++++++- > > 3 files changed, 79 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > > index 990b6670222e..50817fd2c912 100644 > > --- a/drivers/cxl/cxl.h > > +++ b/drivers/cxl/cxl.h > > @@ -90,6 +90,8 @@ static inline int cxl_hdm_decoder_count(u32 cap_hdr) > > #define CXLDEV_MBOX_BG_CMD_STATUS_OFFSET 0x18 > > #define CXLDEV_MBOX_PAYLOAD_OFFSET 0x20 > > > > +#define CXL_DOE_PROTOCOL_TABLE_ACCESS 2 > > + > > /* > > * Using struct_group() allows for per register-block-type helper routines, > > * without requiring block-type agnostic code to include the prefix. > > diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h > > index 7235d2f976e5..0dc6988afb30 100644 > > --- a/drivers/cxl/cxlmem.h > > +++ b/drivers/cxl/cxlmem.h > > @@ -168,6 +168,7 @@ struct cxl_endpoint_dvsec_info { > > * Currently only memory devices are represented. > > * > > * @dev: The device associated with this CXL state > > + * @cdat_doe: Auxiliary DOE device capabile of reading CDAT > > * @regs: Parsed register blocks > > * @cxl_dvsec: Offset to the PCIe device DVSEC > > * @payload_size: Size of space for payload > > @@ -200,6 +201,7 @@ struct cxl_endpoint_dvsec_info { > > struct cxl_dev_state { > > struct device *dev; > > > > + struct cxl_doe_dev *cdat_doe; > > struct cxl_regs regs; > > int cxl_dvsec; > > > > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > > index 0dec1f1a3f38..622cac925262 100644 > > --- a/drivers/cxl/pci.c > > +++ b/drivers/cxl/pci.c > > @@ -706,6 +706,80 @@ static int cxl_pci_create_doe_devices(struct pci_dev *pdev) > > return 0; > > } > > > > +static bool cxl_doe_dev_supports_prot(struct cxl_doe_dev *doe_dev, u16 vid, u16 pid) > > +{ > > + struct cxl_doe_drv_state *doe_ds; > > + bool ret; > > + > > + doe_ds = cxl_pci_doe_get_drv(doe_dev); > > + if (!doe_ds) { > > + cxl_pci_doe_put_drv(doe_dev); > > That means the get_drv has a rather unexpected side effect. > Could you move the NULL check into the function so that we don't retain > a reference if it fails? Indeed. I struggled a bit with this because get_* is usually taking a reference on the subject of the get but in this case we are really getting a reference on the device not the driver... I originally open coded this and the functions were 'get_device'... :-/ I think this also may have been why the device was originally part of the driver state. I think this is the better way to code these access functions: static struct cxl_doe_drv_state *cxl_pci_doe_get_drv(struct cxl_doe_dev *doe_dev) { struct cxl_doe_drv_state *cxl_ds; down_read(&doe_dev->driver_access); cxl_ds = auxiliary_get_drvdata(&doe_dev->adev); if (!cxl_ds) up_read(&doe_dev->driver_access); return cxl_ds; } static void cxl_pci_doe_put_drv(struct cxl_doe_drv_state *cxl_ds) { if (!cxl_ds) return; up_read(&cxl_ds->doe_dev->driver_access); } Ira > > > + return false; > > + } > > + ret = pci_doe_supports_prot(doe_ds->doe_mb, vid, pid); > > + cxl_pci_doe_put_drv(doe_dev); > > + return ret; > > +} > > + > > +static int cxl_match_cdat_doe_device(struct device *dev, const void *data) > > +{ > > + const struct cxl_dev_state *cxlds = data; > > + struct auxiliary_device *adev = to_auxiliary_dev(dev); > > + struct cxl_doe_dev *doe_dev; > > + > > + /* Ensure this is a DOE device */ > > + if (strcmp(DOE_DEV_NAME, adev->name)) > > + return 0; > > + > > + /* Determine if this auxiliary device belongs to the cxlds */ > > + if (cxlds->dev != dev->parent) > > + return 0; > > + > > + doe_dev = container_of(adev, struct cxl_doe_dev, adev); > > + > > + /* If it is one of ours check for the CDAT protocol */ > > + if (!cxl_doe_dev_supports_prot(doe_dev, PCI_DVSEC_VENDOR_ID_CXL, > > + CXL_DOE_PROTOCOL_TABLE_ACCESS)) > > + return 0; > > + > > + return 1; > > +} > > + > > +static void drop_cdat_doe_ref(void *data) > > +{ > > + struct cxl_doe_dev *cdat_doe = data; > > + > > + put_device(&cdat_doe->adev.dev); > > +} > > + > > +static int cxl_setup_doe_devices(struct cxl_dev_state *cxlds) > > +{ > > + struct device *dev = cxlds->dev; > > + struct pci_dev *pdev = to_pci_dev(dev); > > + struct auxiliary_device *adev; > > + int rc; > > + > > + rc = cxl_pci_create_doe_devices(pdev); > > + if (rc) > > + return rc; > > + > > + adev = auxiliary_find_device(NULL, cxlds, &cxl_match_cdat_doe_device); > > + > > + if (adev) { > > + struct cxl_doe_dev *doe_dev = container_of(adev, > > + struct cxl_doe_dev, > > + adev); > > + > > + /* auxiliary_find_device() takes the reference */ > > + rc = devm_add_action_or_reset(dev, drop_cdat_doe_ref, doe_dev); > > + if (rc) > > + return rc; > > + cxlds->cdat_doe = doe_dev; > > + } > > + > > + return 0; > > +} > > + > > static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > { > > struct cxl_register_map map; > > @@ -772,7 +846,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > if (rc) > > return rc; > > > > - rc = cxl_pci_create_doe_devices(pdev); > > + rc = cxl_setup_doe_devices(cxlds); > > if (rc) > > return rc; > > >