ilog2 overkill in ieee80211_get_hdrlen?

[bruno randolf <bruno@thinktube.com>]

hello!

just a question...

in 'net/mac80211/util.c', in ieee80211_get_hdrlen (line 175), a function ilog2 
is used to determine the number of bits to shift for 
IEEE80211_STYPE_QOS_DATA. isn't that a bit of an overkill when we could just 
do >> 6? i mean IEEE80211_STYPE_QOS_DATA isn't going to change after all...

		/*
		 * The QoS Control field is two bytes and its presence is
		 * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
		 * hdrlen if that bit is set.
		 * This works by masking out the bit and shifting it to
		 * bit position 1 so the result has the value 0 or 2.
		 */
		hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
				>> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);

i don't know if there is a reason for this, but it all seems overly 
complicated to me.

if (fc & IEEE80211_STYPE_QOS_DATA)
	hdrlen += 2;

would be a bit more readable.

bruno