> > Which buffer? skb->data..skb->tail? And isn't that, in mac80211's case, > > at least currently all the buffer anyway? > > Right. > > For TSO or cases using frag lists of frag page vectors, it gets > more complicated. Yeah, but at least right now we don't accept any of those. That might change, but even then we'll only care about the headroom (and maybe for TKIP the crypto MIC that's at the end, assuming the hardware does the encryption which it usually does), but we can stick that elsewhere and just DMA it on. > Basically, skb_header_cloned()==false means that you can modify > anything covered by skb->data..skb->tail Ok. > > Interesting point. I'll have to see when socket filters are run, > > wpa_supplicant could have a tap open I think. Maybe that's why I'm > > seeing so many cloned packets. I think I'll stacktrace skb_clone and > > print that out. > > Note that we can even optimize that case even further if we really > have to. > > But try to see why the filter used by WPA Supplicant is not effective. > If the filter fails to match, the packet is free'd immediately using > kfree_skb() which should undo clone'age. Right. I just checked, and realised I remembered wrongly, wpa_supplicant actually binds the socket to the ethertype it wants so dev_queue_xmit_nit() shouldn't be called. I'll have to check why I got so many cloned packets, best see if it still happens with the header_cloned() change. johannes
Attachment:
signature.asc
Description: This is a digitally signed message part
