Re: [9fans] ether8139.c fix

[jmk@plan9.bell-labs.com]

OK. I think we all got confused about this. Turns out I thought
the fix posted by geoff@collyer.net was referring to the 2nd memmove in
the receive code, where the real problem lay and which I had already
fixed some time before. My apologies for not taking time to verify
the fix was what I thought it was.

Anyway, in conjunction with Presotto I've tested the following which
completely replaces the code in rtl8139receive() for handling an OK packet:


		/*
		 * Receive Completed OK.
		 * Very simplistic; there are ways this could be done
		 * without copying, but the juice probably isn't worth
		 * the squeeze.
		 * The packet length includes a 4 byte CRC on the end.
		 */
		capr = (capr+4) % ctlr->rblen;
		p = ctlr->rbstart+capr;
		capr = (capr+length) % ctlr->rblen;

		if((bp = iallocb(length)) != nil){
			if(p+length >= ctlr->rbstart+ctlr->rblen){
				l = ctlr->rbstart+ctlr->rblen - p;
				memmove(bp->wp, p, l);
				bp->wp += l;
				length -= l;
				p = ctlr->rbstart;
			}
			if(length > 0){
				memmove(bp->wp, p, length);
				bp->wp += length;
			}
			bp->wp -= 4;
			etheriq(edev, bp, 1);
		}

		capr = ROUNDUP(capr, 4);
		csr16w(ctlr, Capr, capr-16);