Previously, the devif_poll works in this flow:
devif_poll_xx -> bstop = callback -> continue if !bstop -> poll another
Now we split the polling and callback, so it should work like:
devif_poll_connections -> return true if callback need to be called
-> bstop = callback -> loop if !bstop -> poll again
Conditions:
poll_connections == 0, d_len == 0, break, return 0
poll_connections == 1, d_len == 0, break, return 1 (other stop case,
don't callback)
poll_connections == 1, d_len > 0, callback == 1, break, return 1
poll_connections == 1, d_len > 0, callback == 0, loop
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>