net/ncsi: avoid maybe-uninitialized warning

gcc-4.9 and higher warn about the newly added NSCI code:

net/ncsi/ncsi-manage.c: In function 'ncsi_process_next_channel':
net/ncsi/ncsi-manage.c:1003:2: error: 'old_state' may be used uninitialized in this function [-Werror=maybe-uninitialized]

The warning is a false positive and therefore harmless, but it would be good to
avoid it anyway. I have determined that the barrier in the spin_unlock_irqsave()
is what confuses gcc to the point that it cannot track whether the variable
was unused or not.

This rearranges the code in a way that makes it obvious to gcc that old_state
is always initialized at the time of use, functionally this should not
change anything.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 13 deletions

diff --git a/net/ncsi/ncsi-manage.c b/net/ncsi/ncsi-manage.c
index d627a39ddcd0..ef017b871857 100644
--- a/net/ncsi/ncsi-manage.c
+++ b/net/ncsi/ncsi-manage.c
@@ -982,23 +982,18 @@ int ncsi_process_next_channel(struct ncsi_dev_priv *ndp)
         spin_lock_irqsave(&ndp->lock, flags);
         nc = list_first_or_null_rcu(&ndp->channel_queue,
                                     struct ncsi_channel, link);
-        if (nc) {
-                old_state = xchg(&nc->state, NCSI_CHANNEL_INVISIBLE);
-                list_del_init(&nc->link);
+        if (!nc) {
+                spin_unlock_irqrestore(&ndp->lock, flags);
+                goto out;
         }
+
+        old_state = xchg(&nc->state, NCSI_CHANNEL_INVISIBLE);
+        list_del_init(&nc->link);
+
         spin_unlock_irqrestore(&ndp->lock, flags);
 
         ndp->active_channel = nc;
-        ndp->active_package = nc ? nc->package : NULL;
-        if (!nc) {
-                if (ndp->flags & NCSI_DEV_RESHUFFLE) {
-                        ndp->flags &= ~NCSI_DEV_RESHUFFLE;
-                        return ncsi_choose_active_channel(ndp);
-                }
-
-                ncsi_report_link(ndp, false);
-                return -ENODEV;
-        }
+        ndp->active_package = nc->package;
 
         switch (old_state) {
         case NCSI_CHANNEL_INACTIVE:
@@ -1017,6 +1012,17 @@ int ncsi_process_next_channel(struct ncsi_dev_priv *ndp)
         }
 
         return 0;
+
+out:
+        ndp->active_channel = NULL;
+        ndp->active_package = NULL;
+        if (ndp->flags & NCSI_DEV_RESHUFFLE) {
+                ndp->flags &= ~NCSI_DEV_RESHUFFLE;
+                return ncsi_choose_active_channel(ndp);
+        }
+
+        ncsi_report_link(ndp, false);
+        return -ENODEV;
 }
 
 #if IS_ENABLED(CONFIG_IPV6)