net/ncsi: Avoid unused-value build warning from ia64-linux-gcc
xchg() is used to set NCSI channel's state in order for consistent
access to the state. xchg()'s return value should be used. Otherwise,
one build warning will be raised (with -Wunused-value) as below message
indicates. It is reported by ia64-linux-gcc (GCC) 4.9.0.
net/ncsi/ncsi-manage.c: In function 'ncsi_channel_monitor':
arch/ia64/include/uapi/asm/cmpxchg.h:56:2: warning: value computed is \
not used [-Wunused-value]
((__typeof__(*(ptr))) __xchg((unsigned long) (x), (ptr), sizeof(*(ptr))))
^
net/ncsi/ncsi-manage.c:202:3: note: in expansion of macro 'xchg'
xchg(&nc->state, NCSI_CHANNEL_INACTIVE);
This removes the atomic access to NCSI channel's state avoid the above
build warning. We have to hold the channel's lock when its state is readed
or updated. No functional changes introduced.
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ncsi/ncsi-aen.c b/net/ncsi/ncsi-aen.c
index d463468..b41a661 100644
--- a/net/ncsi/ncsi-aen.c
+++ b/net/ncsi/ncsi-aen.c
@@ -53,7 +53,9 @@
struct ncsi_aen_lsc_pkt *lsc;
struct ncsi_channel *nc;
struct ncsi_channel_mode *ncm;
- unsigned long old_data;
+ bool chained;
+ int state;
+ unsigned long old_data, data;
unsigned long flags;
/* Find the NCSI channel */
@@ -62,20 +64,27 @@
return -ENODEV;
/* Update the link status */
- ncm = &nc->modes[NCSI_MODE_LINK];
lsc = (struct ncsi_aen_lsc_pkt *)h;
+
+ spin_lock_irqsave(&nc->lock, flags);
+ ncm = &nc->modes[NCSI_MODE_LINK];
old_data = ncm->data[2];
- ncm->data[2] = ntohl(lsc->status);
+ data = ntohl(lsc->status);
+ ncm->data[2] = data;
ncm->data[4] = ntohl(lsc->oem_status);
- if (!((old_data ^ ncm->data[2]) & 0x1) ||
- !list_empty(&nc->link))
+
+ chained = !list_empty(&nc->link);
+ state = nc->state;
+ spin_unlock_irqrestore(&nc->lock, flags);
+
+ if (!((old_data ^ data) & 0x1) || chained)
return 0;
- if (!(nc->state == NCSI_CHANNEL_INACTIVE && (ncm->data[2] & 0x1)) &&
- !(nc->state == NCSI_CHANNEL_ACTIVE && !(ncm->data[2] & 0x1)))
+ if (!(state == NCSI_CHANNEL_INACTIVE && (data & 0x1)) &&
+ !(state == NCSI_CHANNEL_ACTIVE && !(data & 0x1)))
return 0;
if (!(ndp->flags & NCSI_DEV_HWA) &&
- nc->state == NCSI_CHANNEL_ACTIVE)
+ state == NCSI_CHANNEL_ACTIVE)
ndp->flags |= NCSI_DEV_RESHUFFLE;
ncsi_stop_channel_monitor(nc);
@@ -97,13 +106,21 @@
if (!nc)
return -ENODEV;
+ spin_lock_irqsave(&nc->lock, flags);
if (!list_empty(&nc->link) ||
- nc->state != NCSI_CHANNEL_ACTIVE)
+ nc->state != NCSI_CHANNEL_ACTIVE) {
+ spin_unlock_irqrestore(&nc->lock, flags);
return 0;
+ }
+ spin_unlock_irqrestore(&nc->lock, flags);
ncsi_stop_channel_monitor(nc);
+ spin_lock_irqsave(&nc->lock, flags);
+ nc->state = NCSI_CHANNEL_INVISIBLE;
+ spin_unlock_irqrestore(&nc->lock, flags);
+
spin_lock_irqsave(&ndp->lock, flags);
- xchg(&nc->state, NCSI_CHANNEL_INACTIVE);
+ nc->state = NCSI_CHANNEL_INACTIVE;
list_add_tail_rcu(&nc->link, &ndp->channel_queue);
spin_unlock_irqrestore(&ndp->lock, flags);