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Sat, 11 Apr 2026 08:02:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1775894538; bh=x/AH9QAAoCuPUN8y8migAOrfyDLPzbk4dDO/e9lMKxE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BAXotC2Yr5clGYTPMxHQEBoeMf5BJMnTpV99tfXBZJOrqN32KRjOXesnB9S44/PJB B3qSXv3mycS9a9+qmahpoDbqEyNOUW1Pu4WEw81W6dWm7rXi0Z4SRvdfvmmpUuTcXE 9uM8970/ijpCOHvP514ItzVYC0R+nJIDySwnLNDP5HoHByuuZ4yEHRI+wxnEpwpO3q pTrIQSqpXAspLFTFe0CMgLMxkNl/5sd01GNesxUXhKC+eVIyMJQ6xy3zdXDDZGJuyv konl4lde2I7y6w9jrGqhpgqf8pWcgZLa6OfYbKfPY17Y8tbe3GpbwGLn7mxJZ5AYcB yHtYsr5lp18bQ== From: =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Bjorn Helgaas , Manivannan Sadhasivam , Lorenzo Pieralisi , Magnus Lindholm , Matt Turner , Richard Henderson , Christophe Leroy , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Dexuan Cui , =?UTF-8?q?Krzysztof=20Ha=C5=82asa?= , Lukas Wunner , "Oliver O'Halloran" , Saurabh Singh Sengar , Shuan He , Srivatsa Bhat , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , linux-pci@vger.kernel.org, linux-alpha@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v4 07/24] PCI/sysfs: Convert PCI resource files to static attributes Date: Sat, 11 Apr 2026 08:01:31 +0000 Message-ID: <20260411080148.471335-8-kwilczynski@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260411080148.471335-1-kwilczynski@kernel.org> References: <20260411080148.471335-1-kwilczynski@kernel.org> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, the PCI resource files (resourceN, resourceN_wc) are dynamically created by pci_create_sysfs_dev_files(), called from both pci_bus_add_device() and the pci_sysfs_init() late_initcall, with only a sysfs_initialized flag for synchronisation. This has caused "duplicate filename" warnings and boot panics when both paths race on the same device. This is especially likely on Devicetree-based platforms, where the PCI host controllers are platform drivers that probe via the driver model, which can happen during or after the late_initcall. As such, pci_bus_add_device() and pci_sysfs_init() are more likely to overlap. Thus, convert to static const attributes with three attribute groups (I/O, UC, WC), each with an .is_bin_visible callback that checks resource flags, BAR length, and non_mappable_bars. A .bin_size callback provides pci_resource_len() to the kernfs node for correct stat and lseek behaviour. As part of this conversion: - Rename pci_read_resource_io() and pci_write_resource_io() to pci_read_resource() and pci_write_resource() since the callbacks are no longer I/O-specific in the static attribute context. - Remove pci_create_resource_files(), pci_remove_resource_files(), and pci_create_attr() which are no longer needed. - Move the __weak stubs outside the #if guard so they remain available for callers converted in subsequent commits. Platforms that do not define the HAVE_PCI_MMAP macro or the ARCH_GENERIC_PCI_MMAP_RESOURCE macro, such as Alpha architecture, continue using their platform-specific resource file creation. For reference, the dynamic creation dates back to the pre-Git era: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/drivers/pci/pci-sysfs.c?id=42298be0eeb5ae98453b3374c36161b05a46c5dc The write-combine support was added in commit 45aec1ae72fc ("x86: PAT export resource_wc in pci sysfs"). Signed-off-by: Krzysztof Wilczyński --- drivers/pci/pci-sysfs.c | 242 +++++++++++++++++++++------------------- include/linux/pci.h | 2 - 2 files changed, 127 insertions(+), 117 deletions(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index ca0074674acc..2922905ff070 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1200,14 +1200,14 @@ static ssize_t pci_resource_io(struct file *filp, struct kobject *kobj, #endif } -static ssize_t pci_read_resource_io(struct file *filp, struct kobject *kobj, +static ssize_t pci_read_resource(struct file *filp, struct kobject *kobj, const struct bin_attribute *attr, char *buf, loff_t off, size_t count) { return pci_resource_io(filp, kobj, attr, buf, off, count, false); } -static ssize_t pci_write_resource_io(struct file *filp, struct kobject *kobj, +static ssize_t pci_write_resource(struct file *filp, struct kobject *kobj, const struct bin_attribute *attr, char *buf, loff_t off, size_t count) { @@ -1261,129 +1261,136 @@ static const struct bin_attribute dev_resource##_bar##_wc_attr = { \ .mmap = pci_mmap_resource_wc, \ } -/** - * pci_remove_resource_files - cleanup resource files - * @pdev: dev to cleanup - * - * If we created resource files for @pdev, remove them from sysfs and - * free their resources. - */ -static void pci_remove_resource_files(struct pci_dev *pdev) +static inline umode_t +__pci_resource_attr_is_visible(struct kobject *kobj, + const struct bin_attribute *a, + int bar, bool write_combine, + unsigned long flags) { - int i; + struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); - for (i = 0; i < PCI_STD_NUM_BARS; i++) { - struct bin_attribute *res_attr; - - res_attr = pdev->res_attr[i]; - if (res_attr) { - sysfs_remove_bin_file(&pdev->dev.kobj, res_attr); - kfree(res_attr); - } - - res_attr = pdev->res_attr_wc[i]; - if (res_attr) { - sysfs_remove_bin_file(&pdev->dev.kobj, res_attr); - kfree(res_attr); - } - } -} - -static int pci_create_attr(struct pci_dev *pdev, int num, int write_combine) -{ - /* allocate attribute structure, piggyback attribute name */ - int name_len = write_combine ? 13 : 10; - struct bin_attribute *res_attr; - char *res_attr_name; - int retval; - - res_attr = kzalloc(sizeof(*res_attr) + name_len, GFP_ATOMIC); - if (!res_attr) - return -ENOMEM; - - res_attr_name = (char *)(res_attr + 1); - - sysfs_bin_attr_init(res_attr); - if (write_combine) { - sprintf(res_attr_name, "resource%d_wc", num); - res_attr->mmap = pci_mmap_resource_wc; - } else { - sprintf(res_attr_name, "resource%d", num); - if (pci_resource_flags(pdev, num) & IORESOURCE_IO) { - res_attr->read = pci_read_resource_io; - res_attr->write = pci_write_resource_io; - if (arch_can_pci_mmap_io()) - res_attr->mmap = pci_mmap_resource_uc; - } else { - res_attr->mmap = pci_mmap_resource_uc; - } - } - if (res_attr->mmap) { - res_attr->f_mapping = iomem_get_mapping; - /* - * generic_file_llseek() consults f_mapping->host to determine - * the file size. As iomem_inode knows nothing about the - * attribute, it's not going to work, so override it as well. - */ - res_attr->llseek = pci_llseek_resource; - } - res_attr->attr.name = res_attr_name; - res_attr->attr.mode = 0600; - res_attr->size = pci_resource_len(pdev, num); - res_attr->private = (void *)(unsigned long)num; - retval = sysfs_create_bin_file(&pdev->dev.kobj, res_attr); - if (retval) { - kfree(res_attr); - return retval; - } - - if (write_combine) - pdev->res_attr_wc[num] = res_attr; - else - pdev->res_attr[num] = res_attr; - - return 0; -} - -/** - * pci_create_resource_files - create resource files in sysfs for @dev - * @pdev: dev in question - * - * Walk the resources in @pdev creating files for each resource available. - */ -static int pci_create_resource_files(struct pci_dev *pdev) -{ - int i; - int retval; - - /* Skip devices with non-mappable BARs */ if (pdev->non_mappable_bars) return 0; - /* Expose the PCI resources from this device as files */ - for (i = 0; i < PCI_STD_NUM_BARS; i++) { + if (!pci_resource_len(pdev, bar)) + return 0; - /* skip empty resources */ - if (!pci_resource_len(pdev, i)) - continue; + if ((pci_resource_flags(pdev, bar) & flags) != flags) + return 0; - retval = pci_create_attr(pdev, i, 0); - /* for prefetchable resources, create a WC mappable file */ - if (!retval && arch_can_pci_mmap_wc() && - pci_resource_flags(pdev, i) & IORESOURCE_PREFETCH) - retval = pci_create_attr(pdev, i, 1); - if (retval) { - pci_remove_resource_files(pdev); - return retval; - } - } - return 0; + if (write_combine && !arch_can_pci_mmap_wc()) + return 0; + + return a->attr.mode; } -#else /* !(defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE)) */ -int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; } -void __weak pci_remove_resource_files(struct pci_dev *dev) { return; } + +static umode_t pci_dev_resource_io_is_visible(struct kobject *kobj, + const struct bin_attribute *a, + int n) +{ + return __pci_resource_attr_is_visible(kobj, a, n, false, + IORESOURCE_IO); +} + +static umode_t pci_dev_resource_uc_is_visible(struct kobject *kobj, + const struct bin_attribute *a, + int n) +{ + return __pci_resource_attr_is_visible(kobj, a, n, false, + IORESOURCE_MEM); +} + +static umode_t pci_dev_resource_wc_is_visible(struct kobject *kobj, + const struct bin_attribute *a, + int n) +{ + return __pci_resource_attr_is_visible(kobj, a, n, true, + IORESOURCE_MEM | IORESOURCE_PREFETCH); +} + +static size_t pci_dev_resource_bin_size(struct kobject *kobj, + const struct bin_attribute *a, + int n) +{ + struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); + + return pci_resource_len(pdev, n); +} + +pci_dev_resource_io_attr(0); +pci_dev_resource_io_attr(1); +pci_dev_resource_io_attr(2); +pci_dev_resource_io_attr(3); +pci_dev_resource_io_attr(4); +pci_dev_resource_io_attr(5); + +pci_dev_resource_uc_attr(0); +pci_dev_resource_uc_attr(1); +pci_dev_resource_uc_attr(2); +pci_dev_resource_uc_attr(3); +pci_dev_resource_uc_attr(4); +pci_dev_resource_uc_attr(5); + +pci_dev_resource_wc_attr(0); +pci_dev_resource_wc_attr(1); +pci_dev_resource_wc_attr(2); +pci_dev_resource_wc_attr(3); +pci_dev_resource_wc_attr(4); +pci_dev_resource_wc_attr(5); + +static const struct bin_attribute *const pci_dev_resource_io_attrs[] = { + &dev_resource0_io_attr, + &dev_resource1_io_attr, + &dev_resource2_io_attr, + &dev_resource3_io_attr, + &dev_resource4_io_attr, + &dev_resource5_io_attr, + NULL, +}; + +static const struct bin_attribute *const pci_dev_resource_uc_attrs[] = { + &dev_resource0_uc_attr, + &dev_resource1_uc_attr, + &dev_resource2_uc_attr, + &dev_resource3_uc_attr, + &dev_resource4_uc_attr, + &dev_resource5_uc_attr, + NULL, +}; + +static const struct bin_attribute *const pci_dev_resource_wc_attrs[] = { + &dev_resource0_wc_attr, + &dev_resource1_wc_attr, + &dev_resource2_wc_attr, + &dev_resource3_wc_attr, + &dev_resource4_wc_attr, + &dev_resource5_wc_attr, + NULL, +}; + +static const struct attribute_group pci_dev_resource_io_attr_group = { + .bin_attrs = pci_dev_resource_io_attrs, + .is_bin_visible = pci_dev_resource_io_is_visible, + .bin_size = pci_dev_resource_bin_size, +}; + +static const struct attribute_group pci_dev_resource_uc_attr_group = { + .bin_attrs = pci_dev_resource_uc_attrs, + .is_bin_visible = pci_dev_resource_uc_is_visible, + .bin_size = pci_dev_resource_bin_size, +}; + +static const struct attribute_group pci_dev_resource_wc_attr_group = { + .bin_attrs = pci_dev_resource_wc_attrs, + .is_bin_visible = pci_dev_resource_wc_is_visible, + .bin_size = pci_dev_resource_bin_size, +}; + #endif +int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; } +void __weak pci_remove_resource_files(struct pci_dev *dev) { } + /** * pci_write_rom - used to enable access to the PCI ROM display * @filp: sysfs file @@ -1861,6 +1868,11 @@ static const struct attribute_group pci_dev_group = { const struct attribute_group *pci_dev_groups[] = { &pci_dev_group, +#if defined(HAVE_PCI_MMAP) || defined(ARCH_GENERIC_PCI_MMAP_RESOURCE) + &pci_dev_resource_io_attr_group, + &pci_dev_resource_uc_attr_group, + &pci_dev_resource_wc_attr_group, +#endif &pci_dev_config_attr_group, &pci_dev_rom_attr_group, &pci_dev_reset_attr_group, diff --git a/include/linux/pci.h b/include/linux/pci.h index 05aceb7f1f37..9c0782899ef9 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -2526,10 +2526,8 @@ int pcibios_alloc_irq(struct pci_dev *dev); void pcibios_free_irq(struct pci_dev *dev); resource_size_t pcibios_default_alignment(void); -#if !defined(HAVE_PCI_MMAP) && !defined(ARCH_GENERIC_PCI_MMAP_RESOURCE) extern int pci_create_resource_files(struct pci_dev *dev); extern void pci_remove_resource_files(struct pci_dev *dev); -#endif #if defined(CONFIG_PCI_MMCONFIG) || defined(CONFIG_ACPI_MCFG) void __init pci_mmcfg_early_init(void); -- 2.53.0