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=-16.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 D5196C4338F for ; Fri, 30 Jul 2021 19:44:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B225560F4A for ; Fri, 30 Jul 2021 19:44:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230408AbhG3Tou (ORCPT ); Fri, 30 Jul 2021 15:44:50 -0400 Received: from mail.kernel.org ([198.145.29.99]:52996 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231163AbhG3Tot (ORCPT ); Fri, 30 Jul 2021 15:44:49 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 012C860F26; Fri, 30 Jul 2021 19:44:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1627674284; bh=dxI61sDpO9sLxBOwYd+sYvdJ3WhWDIoa8/pLRkEcWSs=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=oIwPWX+iQ1dhu8H8h/1dEH080nK4p78Td28/cCuqGFg0anBDEYXC9c3wRDg6sB0Ov XC/EZBtHCB6Fknv7ZhbocHEggIpf00ViKbe9IAJi2CZj/iDxKWaVYir+qmQA6ysQrn WTUEF5+qCkzdNRMI7zgY2Bl4U1FkjdBeugHjd8R4J+uIfejAYT0LausT4dUBmIoV1l kL9lJkARmxOFDEId31r+pz3/CV4uFHHst0fVPJmQsWzLrz7ci1Qzuearpr4Mearjfz G2zL+cFCu4qOj1laUnSGUxJsIaZBP5v+BpqAzuiT9QJxvETFVR1Kv4hSmTA3yYArKY 6xkiUxtJE+SMw== Date: Fri, 30 Jul 2021 14:44:42 -0500 From: Bjorn Helgaas To: Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= Cc: Bjorn Helgaas , Dan Williams , Greg Kroah-Hartman , Daniel Vetter , Kees Cook , Pali =?iso-8859-1?Q?Roh=E1r?= , Oliver O'Halloran , linux-pci@vger.kernel.org Subject: Re: [PATCH v3 1/2] sysfs: Invoke iomem_get_mapping() from the sysfs open callback Message-ID: <20210730194442.GA1091180@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210729233235.1508920-2-kw@linux.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Thu, Jul 29, 2021 at 11:32:34PM +0000, Krzysztof Wilczyński wrote: > Defer invocation of the iomem_get_mapping() to the sysfs open callback > so that it can be executed as needed when the binary sysfs object has > been accessed. > > To do that, convert the "mapping" member of the struct bin_attribute > from a pointer to the struct address_space into a function pointer with > a signature that requires the same return type, and then updates the > sysfs_kf_bin_open() to invoke provided function should the function > pointer be valid. > > Also, convert every invocation of iomem_get_mapping() into a function > pointer assignment, therefore allowing for the iomem_get_mapping() > invocation to be deferred to when the sysfs open callback runs. > > Thus, this change removes the need for the fs_initcalls to complete > before any other sub-system that uses the iomem_get_mapping() would be > able to invoke it safely without leading to a failure and an Oops > related to an invalid iomem_get_mapping() access. > > Suggested-by: Dan Williams > Signed-off-by: Dan Williams > Signed-off-by: Krzysztof Wilczyński > Reviewed-by: Dan Williams Acked-by: Bjorn Helgaas > --- > drivers/pci/pci-sysfs.c | 6 +++--- > fs/sysfs/file.c | 2 +- > include/linux/sysfs.h | 2 +- > 3 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c > index 5d63df7c1820..76e5545d0e73 100644 > --- a/drivers/pci/pci-sysfs.c > +++ b/drivers/pci/pci-sysfs.c > @@ -965,7 +965,7 @@ void pci_create_legacy_files(struct pci_bus *b) > b->legacy_io->read = pci_read_legacy_io; > b->legacy_io->write = pci_write_legacy_io; > b->legacy_io->mmap = pci_mmap_legacy_io; > - b->legacy_io->mapping = iomem_get_mapping(); > + b->legacy_io->mapping = iomem_get_mapping; > pci_adjust_legacy_attr(b, pci_mmap_io); > error = device_create_bin_file(&b->dev, b->legacy_io); > if (error) > @@ -978,7 +978,7 @@ void pci_create_legacy_files(struct pci_bus *b) > b->legacy_mem->size = 1024*1024; > b->legacy_mem->attr.mode = 0600; > b->legacy_mem->mmap = pci_mmap_legacy_mem; > - b->legacy_io->mapping = iomem_get_mapping(); > + b->legacy_io->mapping = iomem_get_mapping; > pci_adjust_legacy_attr(b, pci_mmap_mem); > error = device_create_bin_file(&b->dev, b->legacy_mem); > if (error) > @@ -1195,7 +1195,7 @@ static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) > } > } > if (res_attr->mmap) > - res_attr->mapping = iomem_get_mapping(); > + res_attr->mapping = iomem_get_mapping; > res_attr->attr.name = res_attr_name; > res_attr->attr.mode = 0600; > res_attr->size = pci_resource_len(pdev, num); > diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c > index 9aefa7779b29..a3ee4c32a264 100644 > --- a/fs/sysfs/file.c > +++ b/fs/sysfs/file.c > @@ -175,7 +175,7 @@ static int sysfs_kf_bin_open(struct kernfs_open_file *of) > struct bin_attribute *battr = of->kn->priv; > > if (battr->mapping) > - of->file->f_mapping = battr->mapping; > + of->file->f_mapping = battr->mapping(); > > return 0; > } > diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h > index a12556a4b93a..d5bcc897583c 100644 > --- a/include/linux/sysfs.h > +++ b/include/linux/sysfs.h > @@ -176,7 +176,7 @@ struct bin_attribute { > struct attribute attr; > size_t size; > void *private; > - struct address_space *mapping; > + struct address_space *(*mapping)(void); > ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *, > char *, loff_t, size_t); > ssize_t (*write)(struct file *, struct kobject *, struct bin_attribute *, > -- > 2.32.0 >