s390/qdio: remove 'merge_pending' mechanism
For non-QEBSM devices, get_buf_states() merges PENDING and EMPTY buffers into a single group of finished buffers. To allow the upper-layer driver to differentiate between the two states, qdio_check_pending() looks at each buffer's state again and sets the sbal_state flag to QDIO_OUTBUF_STATE_FLAG_PENDING accordingly. So effectively we're spending overhead on _every_ Output Queue inspection, just to avoid some additional TX completion calls in case a group of buffers has completed with mixed EMPTY / PENDING state. Given that PENDING buffers should rarely occur, this is a bad trade-off. In particular so as the additional checks in get_buf_states() affect _all_ device types (even those that don't use the PENDING state). Rip it all out, and just report the PENDING completions separately as we already do for QEBSM devices. Signed-off-by:Julian Wiedmann <jwi@linux.ibm.com> Reviewed-by:
Benjamin Block <bblock@linux.ibm.com> Signed-off-by:
Vasily Gorbik <gor@linux.ibm.com>
parent
7940eaf2
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