tree 3c77642d10862aa9eea9c9366090941c18b69ac3
parent ab5b5342fd0ba5b9a2f58a94c5d41dd074b7c48e
author Johannes Berg <johannes@sipsolutions.net> 1249656135 +0200
committer John W. Linville <linville@tuxdriver.com> 1250255624 -0400

mac80211: allow DMA optimisation

If we have a lot of frames to transmit at once, for
instance with fragmentation, it can be an optimisation
to only tell the DMA engine about them on the last
fragment/frame to avoid banging the IO too much. This
patch allows implementation such an optimisation by
telling the driver when more frames can be expected.

Currently, this is used by mac80211 only on fragmented
frames, but could also be used in the future on other
frames when the queue was full and there are multiple
frames pending.

Note that drivers need to be careful when using this
flag, they need to kick their DMA engines not just
when this flag is clear, but also when the queue gets
full so that progress can be made.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>