This commit updates the btl interface to change the parameters
passed to receive callbacks. The interface used to pass the tag,
a btl base descriptor, and the callback context. Most of the
values in the btl base descriptor were unused and only helped
simplify the callbacks from the self btl. All of the arguments
have now been replaced with a single receive callback descriptor.
This descriptor contains the incoming endpoint, data segment(s),
tag, and callback context. All btls have been updated to use
the new callback and the btl interface version has been bumped
to v3.2.0.
As part of this change the descriptor argument (and the segments
contained within it) have been marked as const. The were treated
as const before but this change could allow the compiler to make
better optimization decisions and will enforce that the callback
does not attempt to change the data in the descriptor.
Signed-off-by: Nathan Hjelm <hjelmn@google.com>
88f51fbb8e