Generalize it to also tidy up allocation of receive DMA maps. And change a
few of the symbol names involved to (1) make sure all uses have been fixed
and (2) make it clearer what's actually going on.
Previously the driver was using DMA maps off the free list without fully
allocating them, apparently in order to save two or three lines releasing
them on error paths. According to the submitter of the PR (H.Saito) this
was causing it to reuse a map already in use when under load, resulting
in panics.
I'm not sure if that ought to have been possible or if it reflected an
interrupt handling bug somewhere else, but the change is an improvement
regardless, so we'll go with it.
Compile-tested only, but I've crosschecked the diffs and all that and it's
a pretty noninvasive change.
(Is anyone actually using this driver rather than tlp?)
3781289e95