net/ncsi: avoid maybe-uninitialized warning (a1b43edd) · Commits · 戴 / test

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>

net/ncsi/ncsi-manage.c

+19 −13

Original line number	Diff line number	Diff line
		@@ -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) {
		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)

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