[PATCH updated 1/2] pci: separate out pci_add_dynid()

[PATCH updated 1/2] pci: separate out pci_add_dynid()

[Tejun Heo]

Separate out pci_add_dynid() from store_new_id() and export it so that
in-kernel code can add PCI IDs dynamically.  As the function will be
available regardless of HOTPLUG, put it and pull pci_free_dynids()
outside of CONFIG_HOTPLUG.

This will be used by pci-stub to initialize initial IDs via module
param.

While at it, remove bogus get_driver() failure check.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Reviewed-by: Grant Grundler <grundler@parisc-linux.org>
---
These two patches allow preventing built-in drivers from attaching to
devices with certain IDs.  EXPORT_SYMBOL() changed to
EXPORT_SYMBOL_GPL() as suggested by Greg and patch description updated
to mention drop of the bogus failure condition.

Thanks.

 drivers/pci/pci-driver.c |  119 +++++++++++++++++++++++++++++------------------
 include/linux/pci.h      |    5 +
 2 files changed, 79 insertions(+), 45 deletions(-)

Index: ata/drivers/pci/pci-driver.c
===================================================================
--- ata.orig/drivers/pci/pci-driver.c
+++ ata/drivers/pci/pci-driver.c
@@ -19,37 +19,98 @@
 #include <linux/cpu.h>
 #include "pci.h"

-/*
- * Dynamic device IDs are disabled for !CONFIG_HOTPLUG
- */
-
 struct pci_dynid {
 	struct list_head node;
 	struct pci_device_id id;
 };

-#ifdef CONFIG_HOTPLUG
+/**
+ * pci_add_dynid - add a new PCI device ID to this driver and re-probe devices
+ * @drv: target pci driver
+ * @vendor: PCI vendor ID
+ * @device: PCI device ID
+ * @subvendor: PCI subvendor ID
+ * @subdevice: PCI subdevice ID
+ * @class: PCI class
+ * @class_mask: PCI class mask
+ * @driver_data: private driver data
+ *
+ * Adds a new dynamic pci device ID to this driver and causes the
+ * driver to probe for all devices again.  @drv must have been
+ * registered prior to calling this function.
+ *
+ * CONTEXT:
+ * Does GFP_KERNEL allocation.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
+ */
+int pci_add_dynid(struct pci_driver *drv,
+		  unsigned int vendor, unsigned int device,
+		  unsigned int subvendor, unsigned int subdevice,
+		  unsigned int class, unsigned int class_mask,
+		  unsigned long driver_data)
+{
+	struct pci_dynid *dynid;
+	int retval;
+
+	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
+	if (!dynid)
+		return -ENOMEM;
+
+	dynid->id.vendor = vendor;
+	dynid->id.device = device;
+	dynid->id.subvendor = subvendor;
+	dynid->id.subdevice = subdevice;
+	dynid->id.class = class;
+	dynid->id.class_mask = class_mask;
+	dynid->id.driver_data = driver_data;

+	spin_lock(&drv->dynids.lock);
+	list_add_tail(&dynid->node, &drv->dynids.list);
+	spin_unlock(&drv->dynids.lock);
+
+	get_driver(&drv->driver);
+	retval = driver_attach(&drv->driver);
+	put_driver(&drv->driver);
+
+	return retval;
+}
+
+static void pci_free_dynids(struct pci_driver *drv)
+{
+	struct pci_dynid *dynid, *n;
+
+	spin_lock(&drv->dynids.lock);
+	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
+		list_del(&dynid->node);
+		kfree(dynid);
+	}
+	spin_unlock(&drv->dynids.lock);
+}
+
+/*
+ * Dynamic device ID manipulation via sysfs is disabled for !CONFIG_HOTPLUG
+ */
+#ifdef CONFIG_HOTPLUG
 /**
- * store_new_id - add a new PCI device ID to this driver and re-probe devices
+ * store_new_id - sysfs frontend to pci_add_dynid()
  * @driver: target device driver
  * @buf: buffer for scanning device ID data
  * @count: input size
  *
- * Adds a new dynamic pci device ID to this driver,
- * and causes the driver to probe for all devices again.
+ * Allow PCI IDs to be added to an existing driver via sysfs.
  */
 static ssize_t
 store_new_id(struct device_driver *driver, const char *buf, size_t count)
 {
-	struct pci_dynid *dynid;
 	struct pci_driver *pdrv = to_pci_driver(driver);
 	const struct pci_device_id *ids = pdrv->id_table;
 	__u32 vendor, device, subvendor=PCI_ANY_ID,
 		subdevice=PCI_ANY_ID, class=0, class_mask=0;
 	unsigned long driver_data=0;
 	int fields=0;
-	int retval=0;
+	int retval;

 	fields = sscanf(buf, "%x %x %x %x %x %x %lx",
 			&vendor, &device, &subvendor, &subdevice,
@@ -72,27 +133,8 @@ store_new_id(struct device_driver *drive
 			return retval;
 	}

-	dynid = kzalloc(sizeof(*dynid), GFP_KERNEL);
-	if (!dynid)
-		return -ENOMEM;
-
-	dynid->id.vendor = vendor;
-	dynid->id.device = device;
-	dynid->id.subvendor = subvendor;
-	dynid->id.subdevice = subdevice;
-	dynid->id.class = class;
-	dynid->id.class_mask = class_mask;
-	dynid->id.driver_data = driver_data;
-
-	spin_lock(&pdrv->dynids.lock);
-	list_add_tail(&dynid->node, &pdrv->dynids.list);
-	spin_unlock(&pdrv->dynids.lock);
-
-	if (get_driver(&pdrv->driver)) {
-		retval = driver_attach(&pdrv->driver);
-		put_driver(&pdrv->driver);
-	}
-
+	retval = pci_add_dynid(pdrv, vendor, device, subvendor, subdevice,
+			       class, class_mask, driver_data);
 	if (retval)
 		return retval;
 	return count;
@@ -145,19 +187,6 @@ store_remove_id(struct device_driver *dr
 }
 static DRIVER_ATTR(remove_id, S_IWUSR, NULL, store_remove_id);

-static void
-pci_free_dynids(struct pci_driver *drv)
-{
-	struct pci_dynid *dynid, *n;
-
-	spin_lock(&drv->dynids.lock);
-	list_for_each_entry_safe(dynid, n, &drv->dynids.list, node) {
-		list_del(&dynid->node);
-		kfree(dynid);
-	}
-	spin_unlock(&drv->dynids.lock);
-}
-
 static int
 pci_create_newid_file(struct pci_driver *drv)
 {
@@ -186,7 +215,6 @@ static void pci_remove_removeid_file(str
 	driver_remove_file(&drv->driver, &driver_attr_remove_id);
 }
 #else /* !CONFIG_HOTPLUG */
-static inline void pci_free_dynids(struct pci_driver *drv) {}
 static inline int pci_create_newid_file(struct pci_driver *drv)
 {
 	return 0;
@@ -1106,6 +1134,7 @@ static int __init pci_driver_init(void)

 postcore_initcall(pci_driver_init);

+EXPORT_SYMBOL_GPL(pci_add_dynid);
 EXPORT_SYMBOL(pci_match_id);
 EXPORT_SYMBOL(__pci_register_driver);
 EXPORT_SYMBOL(pci_unregister_driver);
Index: ata/include/linux/pci.h
===================================================================
--- ata.orig/include/linux/pci.h
+++ ata/include/linux/pci.h
@@ -794,6 +794,11 @@ int __must_check __pci_register_driver(s
 void pci_unregister_driver(struct pci_driver *dev);
 void pci_remove_behind_bridge(struct pci_dev *dev);
 struct pci_driver *pci_dev_driver(const struct pci_dev *dev);
+int pci_add_dynid(struct pci_driver *drv,
+		  unsigned int vendor, unsigned int device,
+		  unsigned int subvendor, unsigned int subdevice,
+		  unsigned int class, unsigned int class_mask,
+		  unsigned long driver_data);
 const struct pci_device_id *pci_match_id(const struct pci_device_id *ids,
 					 struct pci_dev *dev);
 int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max,

[PATCH 2/2] pci-stub: add pci_stub.ids parameter

[Tejun Heo]

Add ids module parameter which allows specifying initial IDs for the
pci-stub driver.  When built into the kernel, pci-stub is linked
before any real pci drivers and by setting up IDs from initialization
it can prevent built-in drivers from attaching to specific devices.

While at it, make pci_stub_probe() print out about devices it grabbed
to weed out "but my controller isn't being probed" bug reports.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
Unchanged from the first posting.

Thanks.

 drivers/pci/pci-stub.c |   45 ++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 44 insertions(+), 1 deletion(-)

Index: ata/drivers/pci/pci-stub.c
===================================================================
--- ata.orig/drivers/pci/pci-stub.c
+++ ata/drivers/pci/pci-stub.c
@@ -19,8 +19,16 @@
 #include <linux/module.h>
 #include <linux/pci.h>

+static char ids[1024] __initdata;
+
+module_param_string(ids, ids, sizeof(ids), 0);
+MODULE_PARM_DESC(ids, "Initial PCI IDs to add to the stub driver, format is "
+		 "\"vendor:device[:subvendor[:subdevice[:class[:class_mask]]]]\""
+		 " and multiple comma separated entries can be specified");
+
 static int pci_stub_probe(struct pci_dev *dev, const struct pci_device_id *id)
 {
+	dev_printk(KERN_INFO, &dev->dev, "claimed by stub\n");
 	return 0;
 }

@@ -32,7 +40,42 @@ static struct pci_driver stub_driver = {

 static int __init pci_stub_init(void)
 {
-	return pci_register_driver(&stub_driver);
+	char *p, *id;
+	int rc;
+
+	rc = pci_register_driver(&stub_driver);
+	if (rc)
+		return rc;
+
+	/* add ids specified in the module parameter */
+	p = ids;
+	while ((id = strsep(&p, ","))) {
+		unsigned int vendor, device, subvendor = PCI_ANY_ID,
+			subdevice = PCI_ANY_ID, class=0, class_mask=0;
+		int fields;
+
+		fields = sscanf(id, "%x:%x:%x:%x:%x:%x",
+				&vendor, &device, &subvendor, &subdevice,
+				&class, &class_mask);
+
+		if (fields < 2) {
+			printk(KERN_WARNING
+			       "pci-stub: invalid id string \"%s\"\n", id);
+			continue;
+		}
+
+		printk(KERN_INFO
+		       "pci-stub: add %04X:%04X sub=%04X:%04X cls=%08X/%08X\n",
+		       vendor, device, subvendor, subdevice, class, class_mask);
+
+		rc = pci_add_dynid(&stub_driver, vendor, device,
+				   subvendor, subdevice, class, class_mask, 0);
+		if (rc)
+			printk(KERN_WARNING
+			       "pci-stub: failed to add dynamic id (%d)\n", rc);
+	}
+
+	return 0;
 }

 static void __exit pci_stub_exit(void)

Re: [PATCH 2/2] pci-stub: add pci_stub.ids parameter

[Jesse Barnes]

On Thu, 03 Sep 2009 15:27:27 +0900
Tejun Heo <tj@kernel.org> wrote:

> Add ids module parameter which allows specifying initial IDs for the
> pci-stub driver.  When built into the kernel, pci-stub is linked
> before any real pci drivers and by setting up IDs from initialization
> it can prevent built-in drivers from attaching to specific devices.
> 
> While at it, make pci_stub_probe() print out about devices it grabbed
> to weed out "but my controller isn't being probed" bug reports.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> ---
> Unchanged from the first posting.

Applied these two to linux-next, thanks.

-- 
Jesse Barnes, Intel Open Source Technology Center