Re: [RFT PATCH 7/9] ethtool: prepare for larger netdev_features_t type
From: Ben Hutchings <hidden>
Date: 2011-06-20 21:17:01
On Mon, 2011-06-20 at 21:14 +0200, Michał Mirosław wrote: [...]
quoted hunk ↗ jump to hunk
@@ -125,19 +131,26 @@ static int ethtool_set_features(struct net_device *dev, void __user *useraddr) if (copy_from_user(features, useraddr, sizeof(features))) return -EFAULT; - if (features[0].valid & ~NETIF_F_ETHTOOL_BITS) + /* I wonder if the compiler will be smart enough to loop-unroll + * and optimize this... (no worries if not) --mq */ + for (i = ETHTOOL_DEV_FEATURE_WORDS; i-- > 0; ) { + valid = (valid << 32)|features[i].valid; + wanted = (wanted << 32)|features[i].requested; + }
[...]
I don't know (or care) about optimisation of this, but I would expect
gcc to complain about shifting a 32-bit value by 32 bits. I suggest you
write this as:
for (i = 0; i < ETHTOOL_DEV_FEATURE_WORDS; ++i) {
valid |= (netdev_features_t)features[i].valid << 32 *i;
wanted |= (netdev_features_t)features[i].requested << 32 *i;
}
Ben.
--
Ben Hutchings, Senior Software Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.