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s390/qdio: simplify ACK tracking 

Current code uses a 'polling' flag to keep track of whether an Input
Queue has any ACKed SBALs. QEBSM devices might have multiple ACKed
SBALs, and those are tracked separately with 'ack_count'.

By also setting ack_count for non-QEBSM devices (to a fixed value of 1),
we can use 'ack_count != 0' as replacement for the polling flag.

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 2019-11-25 14:18:29 +01:00 committed by Vasily Gorbik
parent fcd98d4002
commit 0b6f499022
3 changed files with 14 additions and 24 deletions
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4
drivers/s390/cio/qdio.h
View File

@ -182,11 +182,9 @@ enum qdio_queue_irq_states {
};
struct qdio_input_q {
/* input buffer acknowledgement flag */
int polling;
/* first ACK'ed buffer */
int ack_start;
/* how much sbals are acknowledged with qebsm */
/* how many SBALs are acknowledged */
int ack_count;
/* last time of noticing incoming data */
u64 timestamp;

5
drivers/s390/cio/qdio_debug.c
View File

@ -124,9 +124,8 @@ static int qstat_show(struct seq_file *m, void *v)
seq_printf(m, "nr_used: %d ftc: %d\n",
atomic_read(&q->nr_buf_used), q->first_to_check);
if (q->is_input_q) {
seq_printf(m, "polling: %d ack start: %d ack count: %d\n",
q->u.in.polling, q->u.in.ack_start,
q->u.in.ack_count);
seq_printf(m, "ack start: %d ack count: %d\n",
q->u.in.ack_start, q->u.in.ack_count);
seq_printf(m, "DSCI: %x IRQs disabled: %u\n",
*(u8 *)q->irq_ptr->dsci,
test_bit(QDIO_QUEUE_IRQS_DISABLED,

29
drivers/s390/cio/qdio_main.c
View File

@ -393,19 +393,15 @@ int debug_get_buf_state(struct qdio_q *q, unsigned int bufnr,
static inline void qdio_stop_polling(struct qdio_q *q)
{
if (!q->u.in.polling)
if (!q->u.in.ack_count)
return;
q->u.in.polling = 0;
qperf_inc(q, stop_polling);
/* show the card that we are not polling anymore */
if (is_qebsm(q)) {
set_buf_states(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT,
q->u.in.ack_count);
q->u.in.ack_count = 0;
} else
set_buf_state(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT);
set_buf_states(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT,
q->u.in.ack_count);
q->u.in.ack_count = 0;
}
static inline void account_sbals(struct qdio_q *q, unsigned int count)
@ -451,8 +447,7 @@ static inline void inbound_primed(struct qdio_q *q, unsigned int start,
/* for QEBSM the ACK was already set by EQBS */
if (is_qebsm(q)) {
if (!q->u.in.polling) {
q->u.in.polling = 1;
if (!q->u.in.ack_count) {
q->u.in.ack_count = count;
q->u.in.ack_start = start;
return;
@ -471,12 +466,12 @@ static inline void inbound_primed(struct qdio_q *q, unsigned int start,
* or by the next inbound run.
*/
new = add_buf(start, count - 1);
if (q->u.in.polling) {
if (q->u.in.ack_count) {
/* reset the previous ACK but first set the new one */
set_buf_state(q, new, SLSB_P_INPUT_ACK);
set_buf_state(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT);
} else {
q->u.in.polling = 1;
q->u.in.ack_count = 1;
set_buf_state(q, new, SLSB_P_INPUT_ACK);
}
@ -1479,13 +1474,12 @@ static int handle_inbound(struct qdio_q *q, unsigned int callflags,
qperf_inc(q, inbound_call);
if (!q->u.in.polling)
if (!q->u.in.ack_count)
goto set;
/* protect against stop polling setting an ACK for an emptied slsb */
if (count == QDIO_MAX_BUFFERS_PER_Q) {
/* overwriting everything, just delete polling status */
q->u.in.polling = 0;
q->u.in.ack_count = 0;
goto set;
} else if (buf_in_between(q->u.in.ack_start, bufnr, count)) {
@ -1495,15 +1489,14 @@ static int handle_inbound(struct qdio_q *q, unsigned int callflags,
diff = sub_buf(diff, q->u.in.ack_start);
q->u.in.ack_count -= diff;
if (q->u.in.ack_count <= 0) {
q->u.in.polling = 0;
q->u.in.ack_count = 0;
goto set;
}
q->u.in.ack_start = add_buf(q->u.in.ack_start, diff);
} else {
/* the only ACK will be deleted */
q->u.in.ack_count = 0;
}
else
/* the only ACK will be deleted, so stop polling */
q->u.in.polling = 0;
}
set: