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s390/qdio: add IRQ reduction for error SBALs 

SBALs in PRIMED or ERROR state represent new work on the Input Queue.
But while inbound_primed() does all sorts of ACK management for new
PRIMED work, the same handling is currently missing for ERROR work.
In particular the path for ERROR work doesn't clear up _old_ ACKs.

Treat ERROR work the same as PRIMED work, but consider that the QEBSM
auto-ACK feature doesn't apply here. So we need to set the ACK manually,
as if it was a non-QEBSM device.

Note that this doesn't aspire to actually improve performance, the main
goal is to just unify the code paths and have consistent behaviour.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
This commit is contained in:
Julian Wiedmann 2020-04-21 10:38:18 +02:00 committed by Vasily Gorbik
parent 1db85d0e73
commit c70d82e966
1 changed files with 11 additions and 12 deletions
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23
drivers/s390/cio/qdio_main.c
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@ -438,15 +438,12 @@ static void process_buffer_error(struct qdio_q *q, unsigned int start,
q->sbal[start]->element[15].sflags);
}
static inline void inbound_primed(struct qdio_q *q, unsigned int start,
int count)
static inline void inbound_handle_work(struct qdio_q *q, unsigned int start,
int count, bool auto_ack)
{
int new;
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim:%1d %02x", q->nr, count);
/* for QEBSM the ACK was already set by EQBS */
if (is_qebsm(q)) {
if (auto_ack) {
if (!q->u.in.ack_count) {
q->u.in.ack_count = count;
q->u.in.ack_start = start;
@ -507,19 +504,21 @@ static int get_inbound_buffer_frontier(struct qdio_q *q, unsigned int start)
switch (state) {
case SLSB_P_INPUT_PRIMED:
inbound_primed(q, start, count);
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim:%1d %02x", q->nr,
count);
inbound_handle_work(q, start, count, is_qebsm(q));
if (atomic_sub_return(count, &q->nr_buf_used) == 0)
qperf_inc(q, inbound_queue_full);
if (q->irq_ptr->perf_stat_enabled)
account_sbals(q, count);
return count;
case SLSB_P_INPUT_ERROR:
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in err:%1d %02x", q->nr,
count);
process_buffer_error(q, start, count);
/*
* Interrupts may be avoided as long as the error is present
* so change the buffer state immediately to avoid starvation.
*/
set_buf_states(q, start, SLSB_P_INPUT_NOT_INIT, count);
inbound_handle_work(q, start, count, false);
if (atomic_sub_return(count, &q->nr_buf_used) == 0)
qperf_inc(q, inbound_queue_full);
if (q->irq_ptr->perf_stat_enabled)