static u32 ath_pkt_duration(struct ath_softc *sc, u8 rix, int pktlen,
			    int width, int half_gi, bool shortPreamble)
{
	u32 nbits, nsymbits, duration, nsymbols;
	int streams;

	/* find number of symbols: PLCP + data */
	streams = HT_RC_2_STREAMS(rix);
	nbits = (pktlen << 3) + OFDM_PLCP_BITS;
	nsymbits = bits_per_symbol[rix % 8][width] * streams;
	nsymbols = (nbits + nsymbits - 1) / nsymbits;

	if (!half_gi)
		duration = SYMBOL_TIME(nsymbols);
	else
		duration = SYMBOL_TIME_HALFGI(nsymbols);

	/* addup duration for legacy/ht training and signal fields */
	duration += L_STF + L_LTF + L_SIG + HT_SIG + HT_STF + HT_LTF(streams);

	return duration;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.