[{"id":3676681,"web_url":"http://patchwork.ozlabs.org/comment/3676681/","msgid":"<36cdf28b-281f-46c7-d4b5-083675b61660@linux.intel.com>","date":"2026-04-13T11:51:47","subject":"Re: [PATCH v4 12/24] alpha/PCI: Use BAR index in sysfs attr->private\n instead of resource pointer","submitter":{"id":83553,"url":"http://patchwork.ozlabs.org/api/people/83553/","name":"Ilpo Järvinen","email":"ilpo.jarvinen@linux.intel.com"},"content":"On Sat, 11 Apr 2026, Krzysztof Wilczyński wrote:\n\n> Currently, Alpha's pci_create_one_attr() stores a resource pointer in\n> attr->private, and pci_mmap_resource() loops through all BARs to find\n> the matching index.\n> \n> Thus, store the BAR index directly in attr->private and retrieve the\n> resource via pci_resource_n(). This eliminates the loop and aligns\n> with the convention used by the generic PCI sysfs code.\n> \n> While at it, add parentheses around the bitwise flag test in\n> pci_mmap_resource() to make the precedence explicit, and to\n> match the preferred style.\n\nProbably not necessary to touch this line now at all as you're going to \nreplace it two patches later anyway so it just adds noise.\n\nReviewed-by: Ilpo Järvinen \n\n> The PCI core change was first added in the commit dca40b186b75 (\"PCI:\n> Use BAR index in sysfs attr->private instead of resource pointer\").\n> \n> Signed-off-by: Krzysztof Wilczyński \n> ---\n> arch/alpha/kernel/pci-sysfs.c | 17 ++++++-----------\n> 1 file changed, 6 insertions(+), 11 deletions(-)\n> \n> diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c\n> index 2324720c3e83..c84867ce31f5 100644\n> --- a/arch/alpha/kernel/pci-sysfs.c\n> +++ b/arch/alpha/kernel/pci-sysfs.c\n> @@ -69,25 +69,20 @@ static int pci_mmap_resource(struct kobject *kobj,\n> \t\t\t struct vm_area_struct *vma, int sparse)\n> {\n> \tstruct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));\n> -\tstruct resource *res = attr->private;\n> +\tint barno = (unsigned long)attr->private;\n> +\tstruct resource *res = pci_resource_n(pdev, barno);\n> \tenum pci_mmap_state mmap_type;\n> \tstruct pci_bus_region bar;\n> -\tint i, ret;\n> +\tint ret;\n> \n> \tret = security_locked_down(LOCKDOWN_PCI_ACCESS);\n> \tif (ret)\n> \t\treturn ret;\n> \n> -\tfor (i = 0; i < PCI_STD_NUM_BARS; i++)\n> -\t\tif (res == &pdev->resource[i])\n> -\t\t\tbreak;\n> -\tif (i >= PCI_STD_NUM_BARS)\n> -\t\treturn -ENODEV;\n> -\n> -\tif (res->flags & IORESOURCE_MEM && iomem_is_exclusive(res->start))\n> +\tif ((res->flags & IORESOURCE_MEM) && iomem_is_exclusive(res->start))\n> \t\treturn -EINVAL;\n> \n> -\tif (!__pci_mmap_fits(pdev, i, vma, sparse))\n> +\tif (!__pci_mmap_fits(pdev, barno, vma, sparse))\n> \t\treturn -EINVAL;\n> \n> \tpcibios_resource_to_bus(pdev->bus, &bar, res);\n> @@ -170,7 +165,7 @@ static int pci_create_one_attr(struct pci_dev *pdev, int num, char *name,\n> \tres_attr->attr.name = name;\n> \tres_attr->attr.mode = S_IRUSR | S_IWUSR;\n> \tres_attr->size = sparse ? size << 5 : size;\n> -\tres_attr->private = &pdev->resource[num];\n> +\tres_attr->private = (void *)(unsigned long)num;\n> \treturn sysfs_create_bin_file(&pdev->dev.kobj, res_attr);\n> }\n> \n>","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linuxppc-dev@lists.ozlabs.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256\n header.s=Intel header.b=NoV4IGcG;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org\n (client-ip=2404:9400:21b9:f100::1; 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a=\"79594851\"","E=Sophos;i=\"6.23,177,1770624000\";\n d=\"scan'208\";a=\"79594851\"","E=Sophos;i=\"6.23,177,1770624000\";\n d=\"scan'208\";a=\"234182329\""],"X-ExtLoop1":"1","From":"=?utf-8?q?Ilpo_J=C3=A4rvinen?= ","Date":"Mon, 13 Apr 2026 14:51:47 +0300 (EEST)","To":"=?iso-8859-2?q?Krzysztof_Wilczy=F1ski?= ","cc":"Bjorn Helgaas , Bjorn Helgaas ,\n Manivannan Sadhasivam ,\n Lorenzo Pieralisi ,\n Magnus Lindholm , Matt Turner ,\n Richard Henderson ,\n Christophe Leroy ,\n Madhavan Srinivasan ,\n Michael Ellerman , Nicholas Piggin ,\n Dexuan Cui ,\n =?iso-8859-2?q?Krzysztof_Ha=B3asa?= ,\n Lukas Wunner , Oliver O'Halloran ,\n Saurabh Singh Sengar ,\n Shuan He ,\n Srivatsa Bhat , linux-pci@vger.kernel.org,\n linux-alpha@vger.kernel.org, linuxppc-dev@lists.ozlabs.org","Subject":"Re: [PATCH v4 12/24] alpha/PCI: Use BAR index in sysfs attr->private\n instead of resource pointer","In-Reply-To":"<20260411080148.471335-13-kwilczynski@kernel.org>","Message-ID":"<36cdf28b-281f-46c7-d4b5-083675b61660@linux.intel.com>","References":"<20260411080148.471335-1-kwilczynski@kernel.org>\n <20260411080148.471335-13-kwilczynski@kernel.org>","X-Mailing-List":"linuxppc-dev@lists.ozlabs.org","List-Id":"","List-Help":"","List-Owner":"","List-Post":"","List-Archive":",\n ","List-Subscribe":",\n ,\n ","List-Unsubscribe":"","Precedence":"list","MIME-Version":"1.0","Content-Type":"multipart/mixed; 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