If bus_dmamap_load_mbuf() fails following a defrag, the caller of
bwn_dma_tx_start() would free the original mbuf after m_defrag() had
already done so. Fix this by returning the defragged mbuf to the
caller instead. Update bwn_pio_tx_start() similarly for consistency.
Reported by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Reviewed by: landonf
Tested by: landonf
MFC after: 3 days
admbug: 820
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D18342
9732b465b4