From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 835F63BED24 for ; Mon, 20 Jul 2026 20:46:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784580388; cv=none; b=f40JduI+ErjyatqM+oWbr8IsuzvOIRdG7y73+GMehWAOHAxdhN1JaOpUTSb/ivbBkk6M0aDUCJbv7AuaDx+hPPgtH2aeW7dy2Bd96sWX6+B6ESSZTllULxqzfrPROqzis+DFRI0RMM6PFOXitlk9SuiwDv2wHWZNBLkm/P5um2A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784580388; c=relaxed/simple; bh=ShSDV/KJtYRQmCnumfL3yH2eBc7NPzSDeoVK7xkU9nM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version:Content-Type; b=jnNnfBBbWvOJUPxgxjqzM4+fqAG9sK18MvUy0qu3PUfTo02xAqQz7zgnmox40FRFuVOyvEWS172dW9yJCNVR2XBWNAE+dTAg6EeKm0eFwS6oNF1t/WXivUgZaztaCbZJOcL5rFAj32rj3z4sE6Xfu+OLZlKQV9cHJnnPR71PKUc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fOYfL9u4; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fOYfL9u4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1570D1F000E9; Mon, 20 Jul 2026 20:46:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784580387; bh=aE2kNppi6KNqKYjvOjOfitNEsS4EvIPoy1Z1HpBTMwQ=; h=From:To:Cc:Subject:Date; b=fOYfL9u4Q1S9i/gAXr/vhZl8ELPGWY4vpyaCUMLVKO1lM1I9BSkhObQKzSjm/N4FP dmAKPk4z8s4TlKvg/Yjo8oKv9oVg84GrZsvqj6M/MGXZBpH3gGVb6UX38vvkCywe4o Ee0AabrXzYHTIljTtZCMolvbwFUIALzpaewUPq4kqP9ucfgi+W+QxiRtHYqW8OaORz XcWooXJtlR9EtPVkuh8J1sgeq8ixrd2fyNoJbNJm56Smgo/B6D/SyaWQO3awlYA6gE NeNAZAxie5OCTqPma6auZY1IOflIctvMKHvuWBKgI10gNLDgByz0fK4f11FUo1EGrr cg+NM6PUXUNEg== From: =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= To: Bjorn Helgaas Cc: Bjorn Helgaas , Manivannan Sadhasivam , Lorenzo Pieralisi , linux-pci@vger.kernel.org Subject: [PATCH] PCI/sysfs: Return -EINVAL for unsupported I/O BAR mmap Date: Mon, 20 Jul 2026 20:46:24 +0000 Message-ID: <20260720204624.1503794-1-kwilczynski@kernel.org> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, mmap() of a resourceN file for an I/O BAR fails with -ENODEV on architectures where arch_can_pci_mmap_io() is 0, such as x86, because the attribute has no mmap callback there and the error comes from the generic kernfs dispatch. This is a side effect of commit e854d8b2a82e ("PCI: Add arch_can_pci_mmap_io() on architectures which can mmap() I/O space"), which removed the mmap callback from the I/O resource attribute on these architectures. Previously the request reached the architecture mmap code and failed with -EINVAL, and the same commit deliberately kept -EINVAL for the identical operation on the procfs interface, so the two PCI userspace interfaces have disagreed ever since. Therefore, add a pci_mmap_resource_io_unsupported() callback that returns -EINVAL and use it as the mmap handler of the I/O resource attribute when arch_can_pci_mmap_io() is 0, so the failure is produced deliberately by PCI code, consistent with the procfs interface and with the behaviour before e854d8b2a82e. Architectures where arch_can_pci_mmap_io() is non-zero keep the real pci_mmap_resource_uc() handler and are unaffected. The mmap() fails either way. Only the reported error changes from -ENODEV to -EINVAL. Fixes: e854d8b2a82e ("PCI: Add arch_can_pci_mmap_io() on architectures which can mmap() I/O space") Signed-off-by: Krzysztof Wilczyński --- drivers/pci/pci-sysfs.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5ec0b245a69b..4cc082929d1a 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1244,7 +1244,16 @@ static loff_t pci_llseek_resource(struct file *filep, .llseek = pci_llseek_resource, \ .mmap = pci_mmap_resource_uc, #else -# define __PCI_RESOURCE_IO_MMAP_ATTRS +static int pci_mmap_resource_io_unsupported(struct file *filp, + struct kobject *kobj, + const struct bin_attribute *attr, + struct vm_area_struct *vma) +{ + return -EINVAL; +} + +# define __PCI_RESOURCE_IO_MMAP_ATTRS \ + .mmap = pci_mmap_resource_io_unsupported, #endif #define pci_dev_resource_io_attr(_bar) \ -- 2.55.0