tree c1ad32d09ce608bb6e59403336770b19c709db06
parent 98085faf49596d408920049eb1bccb4ffe229557
author Andrew Jeffery <andrew@aj.id.au> 1689136053 +0930
committer Andrew Jeffery <andrew@aj.id.au> 1690502413 +0930

transport: pldm_transport_poll(): Adjust return value semantics

Prior, a timeout in pldm_transport_poll() would result in a
pldm_transport_recv() call being issued in pldm_transport_send_recv().
That's not the right course of action as it will translate to a blocking
recv() system call for either of the current transport implementations.
As there's no data present the recv() blocks indefinitely, violating the
timeout constraint.

Instead, align the behaviour with POSIX poll(2)[1], which returns the
number of active descriptors. The number of active descriptors is 0 if a
timeout occurs.

[1]: https://www.man7.org/linux/man-pages/man2/poll.2.html#RETURN_VALUE

Fixes: c1b66f420912 ("requester: Add new APIs to support multiple transports")
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: Id75e8dad49a0ea6081830d0825896094bff0e827