linux-kernel - [PATCH v2 2/2] pci: Support "removable" attribute for PCI devices

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Date:   Fri, 23 Apr 2021 19:16:31 -0700
From:   Rajat Jain <rajatja@...gle.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Alan Stern <stern@...land.harvard.edu>,
        Rajat Jain <rajatja@...gle.com>, linux-kernel@...r.kernel.org,
        linux-pci@...r.kernel.org, linux-usb@...r.kernel.org,
        helgaas@...nel.org
Cc:     rajatxjain@...il.com, jsbarnes@...gle.com, dtor@...gle.com
Subject: [PATCH v2 2/2] pci: Support "removable" attribute for PCI devices

Export the already available info, to the userspace via the
device core, so that userspace can implement whatever policies it
wants to, for external removable devices.

Signed-off-by: Rajat Jain <rajatja@...gle.com>
---
v2: Add documentation

 Documentation/ABI/testing/sysfs-devices-removable |  3 ++-
 drivers/pci/pci-sysfs.c                           |  1 +
 drivers/pci/probe.c                               | 12 ++++++++++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-devices-removable b/Documentation/ABI/testing/sysfs-devices-removable
index e13dddd547b5..daac4f007619 100644
--- a/Documentation/ABI/testing/sysfs-devices-removable
+++ b/Documentation/ABI/testing/sysfs-devices-removable
@@ -14,4 +14,5 @@ Description:
 
 		Currently this is only supported by USB (which infers the
 		information from a combination of hub descriptor bits and
-		platform-specific data such as ACPI).
+		platform-specific data such as ACPI) and PCI (which gets this
+		from ACPI / device tree).
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index f8afd54ca3e1..9302f0076e73 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1582,4 +1582,5 @@ static const struct attribute_group *pci_dev_attr_groups[] = {
 
 const struct device_type pci_dev_type = {
 	.groups = pci_dev_attr_groups,
+	.supports_removable = true,
 };
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 953f15abc850..d1cceee62e1b 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1575,6 +1575,16 @@ static void set_pcie_untrusted(struct pci_dev *dev)
 		dev->untrusted = true;
 }
 
+static void set_pci_dev_removable(struct pci_dev *dev)
+{
+	struct pci_dev *parent = pci_upstream_bridge(dev);
+	if (parent &&
+	    (parent->external_facing || dev_is_removable(&parent->dev)))
+		dev_set_removable(&dev->dev, DEVICE_REMOVABLE);
+	else
+		dev_set_removable(&dev->dev, DEVICE_FIXED);
+}
+
 /**
  * pci_ext_cfg_is_aliased - Is ext config space just an alias of std config?
  * @dev: PCI device
@@ -1819,6 +1829,8 @@ int pci_setup_device(struct pci_dev *dev)
 	/* "Unknown power state" */
 	dev->current_state = PCI_UNKNOWN;
 
+	set_pci_dev_removable(dev);
+
 	/* Early fixups, before probing the BARs */
 	pci_fixup_device(pci_fixup_early, dev);
 
-- 
2.31.1.498.g6c1eba8ee3d-goog