On Mon, 2012-05-07 at 14:01 +0200, Janusz Dziedzic wrote: > 2011/10/26 Arik Nemtsov <arik@xxxxxxxxxx>: > > On Wed, Oct 26, 2011 at 11:59, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: > >> On 10/23/2011 8:21 AM, Arik Nemtsov wrote: > >>> > >>> Some cards can generate CCMP IVs in HW, but require the space for the IV > >>> to be pre-allocated in the frame at the correct offset. Add a key flag > >>> that allows us to achieve this. > >> > >> Is it really that expensive to generate the IV and then not use it that this > >> is worth the extra complexity? This not just makes it more complex but also > >> more expensive in the other case. > >> > > > > Some of the platforms with this chip are pretty weak (host CPU is the > > bottleneck). > > > > We add another "if" for the other case (for a value that's likely in > > the cacheline already). I don't think that's too bad. > > > > Hello, > Why this is only done for CCMP? > Our firmware require such IVs allocation for all modes and currently > we have common code that do that in the driver based on: > iv_len = tx_info->control.hw_key->iv_len > icv_len = tx_info->control.hw_key->icv_len > > /* cw1200 driver */ > skb_push(t->skb, iv_len); > memmove(newhdr, newhdr + iv_len, t->hdrlen); > skb_put(t->skb, icv_len); > .... > > Isn't better to handle all modes in mac80211 base on > IEEE80211_KEY_FLAG_PUT_IV_SPACE or just leave this for the driver? > > I know this is easy to fix in our driver but still we have to remember > that in case of CCMP mac80211 will already do it for us and will not > do that in case of other modes. > So, my proposal is to remove all changes from net/mac80211/wpa.c file > and remember that driver should care about it - in such case > PUT_IV_SPACE will be more generic. I suggest the opposite, make it more generic in mac80211. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
