The 802.1p priority mapping was discussed here — <802.1p Priority in Ethernet Frame>.

When an 802.11 WLAN device sends out a packet, the upper layers should provide an 802.1p priority mapping. The access points that receive the frame should map the 802.1p priority to the appropriate DSCP value and forward the same.

For 802.11 QoS, the 802.1p is mapped to a 4-level QoS mapping for user priority packets. The mapping of 802.1p<=>802.11 is shown below

Enhanced Distributed Co-ordination Function (WMM) – Part 1