[PATCH] PCI: add pci_get_class() to make a safe pci_find_class() like call.

Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

Documentation/pci.txt

@@ -146,7 +146,7 @@ Searching by vendor and device ID:
 
 Searching by class ID (iterate in a similar way):
 
-	pci_find_class(CLASS_ID, dev)
+	pci_get_class(CLASS_ID, dev)
 
 Searching by both vendor/device and subsystem vendor/device ID:
 
@@ -281,5 +281,6 @@ pci_for_each_dev_reverse()	Superseded by pci_find_device_reverse()
 pci_for_each_bus()		Superseded by pci_find_next_bus()
 pci_find_device()		Superseded by pci_get_device()
 pci_find_subsys()		Superseded by pci_get_subsys()
-pcibios_find_class()		Superseded by pci_find_class()
+pcibios_find_class()		Superseded by pci_get_class()
+pci_find_class()		Superseded by pci_get_class()
 pci_(read|write)_*_nodev()	Superseded by pci_bus_(read|write)_*()

drivers/pci/search.c

@@ -348,6 +348,43 @@ pci_find_class(unsigned int class, const struct pci_dev *from)
 	return dev;
 }
 
+/**
+ * pci_get_class - begin or continue searching for a PCI device by class
+ * @class: search for a PCI device with this class designation
+ * @from: Previous PCI device found in search, or %NULL for new search.
+ *
+ * Iterates through the list of known PCI devices.  If a PCI device is
+ * found with a matching @class, the reference count to the device is
+ * incremented and a pointer to its device structure is returned.
+ * Otherwise, %NULL is returned.
+ * A new search is initiated by passing %NULL to the @from argument.
+ * Otherwise if @from is not %NULL, searches continue from next device
+ * on the global list.  The reference count for @from is always decremented
+ * if it is not %NULL.
+ */
+struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
+{
+	struct list_head *n;
+	struct pci_dev *dev;
+
+	WARN_ON(in_interrupt());
+	spin_lock(&pci_bus_lock);
+	n = from ? from->global_list.next : pci_devices.next;
+
+	while (n && (n != &pci_devices)) {
+		dev = pci_dev_g(n);
+		if (dev->class == class)
+			goto exit;
+		n = n->next;
+	}
+	dev = NULL;
+exit:
+	pci_dev_put(from);
+	dev = pci_dev_get(dev);
+	spin_unlock(&pci_bus_lock);
+	return dev;
+}
+
 EXPORT_SYMBOL(pci_find_bus);
 EXPORT_SYMBOL(pci_find_class);
 EXPORT_SYMBOL(pci_find_device);
@@ -356,3 +393,4 @@ EXPORT_SYMBOL(pci_find_slot);
 EXPORT_SYMBOL(pci_get_device);
 EXPORT_SYMBOL(pci_get_subsys);
 EXPORT_SYMBOL(pci_get_slot);
+EXPORT_SYMBOL(pci_get_class);

include/linux/pci.h

@@ -730,6 +730,7 @@ struct pci_dev *pci_get_subsys (unsigned int vendor, unsigned int device,
 				unsigned int ss_vendor, unsigned int ss_device,
 				struct pci_dev *from);
 struct pci_dev *pci_get_slot (struct pci_bus *bus, unsigned int devfn);
+struct pci_dev *pci_get_class (unsigned int class, struct pci_dev *from);
 
 int pci_bus_read_config_byte (struct pci_bus *bus, unsigned int devfn, int where, u8 *val);
 int pci_bus_read_config_word (struct pci_bus *bus, unsigned int devfn, int where, u16 *val);
@@ -892,6 +893,9 @@ static inline struct pci_dev *pci_get_subsys (unsigned int vendor, unsigned int
 unsigned int ss_vendor, unsigned int ss_device, struct pci_dev *from)
 { return NULL; }
 
+static inline struct pci_dev *pci_get_class(unsigned int class, struct pci_dev *from)
+{ return NULL; }
+
 static inline void pci_set_master(struct pci_dev *dev) { }
 static inline int pci_enable_device(struct pci_dev *dev) { return -EIO; }
 static inline void pci_disable_device(struct pci_dev *dev) { }