edac: Add edac_pci_alloc_index()

Add edac_pci_alloc_index(), because for MAPLE platform there may exist
several EDAC driver modules that could make use of edac_pci_ctl_info
structure at the same time.  The index allocation for these structures
should be taken care of by EDAC core.
Signed-off-by: Harry Ciao <qingtao.cao@windriver.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/edac/edac_core.h

@@ -844,6 +844,7 @@ extern void edac_pci_free_ctl_info(struct edac_pci_ctl_info *pci);
 extern void edac_pci_reset_delay_period(struct edac_pci_ctl_info *pci,
 				unsigned long value);
 
+extern int edac_pci_alloc_index(void);
 extern int edac_pci_add_device(struct edac_pci_ctl_info *pci, int edac_idx);
 extern struct edac_pci_ctl_info *edac_pci_del_device(struct device *dev);
 

drivers/edac/edac_pci.c

@@ -30,6 +30,7 @@
 
 static DEFINE_MUTEX(edac_pci_ctls_mutex);
 static LIST_HEAD(edac_pci_list);
+static atomic_t pci_indexes = ATOMIC_INIT(0);
 
 /*
  * edac_pci_alloc_ctl_info
@@ -317,6 +318,19 @@ void edac_pci_reset_delay_period(struct edac_pci_ctl_info *pci,
 }
 EXPORT_SYMBOL_GPL(edac_pci_reset_delay_period);
 
+/*
+ * edac_pci_alloc_index: Allocate a unique PCI index number
+ *
+ * Return:
+ *      allocated index number
+ *
+ */
+int edac_pci_alloc_index(void)
+{
+	return atomic_inc_return(&pci_indexes) - 1;
+}
+EXPORT_SYMBOL_GPL(edac_pci_alloc_index);
+
 /*
  * edac_pci_add_device: Insert the 'edac_dev' structure into the
  * edac_pci global list and create sysfs entries associated with