[PATCH] EDAC: mc numbers refactor 1-of-2

Remove add_mc_to_global_list().  In next patch, this function will be
reimplemented with different semantics.

1 Reimplement add_mc_to_global_list() with semantics that allow the caller to
  determine the ID number for a mem_ctl_info structure.  Then modify
  edac_mc_add_mc() so that the caller specifies the ID number for the new
  mem_ctl_info structure.  Platform-specific code should be able to assign the
  ID numbers in a platform-specific manner.  For instance, on Opteron it makes
  sense to have the ID of the mem_ctl_info structure match the ID of the node
  that the memory controller belongs to.

2 Modify callers of edac_mc_add_mc() so they use the new semantics.

Signed-off-by: Doug Thompson <norsk5@xmission.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 30 insertions, 29 deletions

diff --git a/drivers/edac/edac_mc.c b/drivers/edac/edac_mc.c
index 603de8b49f27..357c95f30fc6 100644
--- a/drivers/edac/edac_mc.c
+++ b/drivers/edac/edac_mc.c
@@ -1632,47 +1632,46 @@ static struct mem_ctl_info *find_mci_by_dev(struct device *dev)
         return NULL;
 }
 
-static int add_mc_to_global_list(struct mem_ctl_info *mci)
+/* Return 0 on success, 1 on failure.
+ * Before calling this function, caller must
+ * assign a unique value to mci->mc_idx.
+ */
+static int add_mc_to_global_list (struct mem_ctl_info *mci)
 {
         struct list_head *item, *insert_before;
         struct mem_ctl_info *p;
-        int i;
 
-        if (list_empty(&mc_devices)) {
-                mci->mc_idx = 0;
-                insert_before = &mc_devices;
-        } else {
-                if (find_mci_by_dev(mci->dev)) {
-                        edac_printk(KERN_WARNING, EDAC_MC,
-                                "%s (%s) %s %s already assigned %d\n",
-                                mci->dev->bus_id, dev_name(mci->dev),
-                                mci->mod_name, mci->ctl_name,
-                                mci->mc_idx);
-                        return 1;
-                }
+        insert_before = &mc_devices;
 
-                insert_before = NULL;
-                i = 0;
+        if (unlikely((p = find_mci_by_dev(mci->dev)) != NULL))
+                goto fail0;
 
-                list_for_each(item, &mc_devices) {
-                        p = list_entry(item, struct mem_ctl_info, link);
+        list_for_each(item, &mc_devices) {
+                p = list_entry(item, struct mem_ctl_info, link);
 
-                        if (p->mc_idx != i) {
-                                insert_before = item;
-                                break;
-                        }
+                if (p->mc_idx >= mci->mc_idx) {
+                        if (unlikely(p->mc_idx == mci->mc_idx))
+                                goto fail1;
 
-                        i++;
+                        insert_before = item;
+                        break;
                 }
-
-                mci->mc_idx = i;
-
-                if (insert_before == NULL)
-                        insert_before = &mc_devices;
         }
 
         list_add_tail_rcu(&mci->link, insert_before);
         return 0;
+
+fail0:
+        edac_printk(KERN_WARNING, EDAC_MC,
+                    "%s (%s) %s %s already assigned %d\n", p->dev->bus_id,
+                    dev_name(p->dev), p->mod_name, p->ctl_name, p->mc_idx);
+        return 1;
+
+fail1:
+        edac_printk(KERN_WARNING, EDAC_MC,
+                    "bug in low-level driver: attempt to assign\n"
+                    "    duplicate mc_idx %d in %s()\n", p->mc_idx, __func__);
+        return 1;
 }
 
 static void complete_mc_list_del(struct rcu_head *head)
@@ -1696,6 +1695,7 @@ static void del_mc_from_global_list(struct mem_ctl_info *mci)
  * edac_mc_add_mc: Insert the 'mci' structure into the mci global list and
  *                 create sysfs entries associated with mci structure
  * @mci: pointer to the mci structure to be added to the list
+ * @mc_idx: A unique numeric identifier to be assigned to the 'mci' structure.
  *
  * Return:
  *      0       Success
@@ -1703,9 +1703,10 @@ static void del_mc_from_global_list(struct mem_ctl_info *mci)
  */
 
 /* FIXME - should a warning be printed if no error detection? correction? */
-int edac_mc_add_mc(struct mem_ctl_info *mci)
+int edac_mc_add_mc(struct mem_ctl_info *mci, int mc_idx)
 {
         debugf0("%s()\n", __func__);
+        mci->mc_idx = mc_idx;
 #ifdef CONFIG_EDAC_DEBUG
         if (edac_debug_level >= 3)
                 edac_mc_dump_mci(mci);