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s390/qdio: remove 'merge_pending' mechanism

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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>
This commit is contained in:
Julian Wiedmann 2021-01-30 13:22:56 +01:00 committed by Vasily Gorbik
parent 7940eaf2e9
commit 2223318c28
3 changed files with 10 additions and 57 deletions
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4
arch/s390/include/asm/qdio.h
View File

@ -250,17 +250,13 @@ struct slsb {
* struct qdio_outbuf_state - SBAL related asynchronous operation information
* (for communication with upper layer programs)
* (only required for use with completion queues)
* @flags: flags indicating state of buffer
* @user: pointer to upper layer program's state information related to SBAL
* (stored in user1 data of QAOB)
*/
struct qdio_outbuf_state {
u8 flags;
void *user;
};
#define QDIO_OUTBUF_STATE_FLAG_PENDING 0x01
#define CHSC_AC1_INITIATE_INPUTQ 0x80

59
drivers/s390/cio/qdio_main.c
View File

@ -202,7 +202,7 @@ again:
*/
static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
unsigned char *state, unsigned int count,
int auto_ack, int merge_pending)
int auto_ack)
{
unsigned char __state = 0;
int i = 1;
@ -217,18 +217,9 @@ static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
if (__state & SLSB_OWNER_CU)
goto out;
if (merge_pending && __state == SLSB_P_OUTPUT_PENDING)
__state = SLSB_P_OUTPUT_EMPTY;
for (; i < count; i++) {
bufnr = next_buf(bufnr);
/* merge PENDING into EMPTY: */
if (merge_pending &&
q->slsb.val[bufnr] == SLSB_P_OUTPUT_PENDING &&
__state == SLSB_P_OUTPUT_EMPTY)
continue;
/* stop if next state differs from initial state: */
if (q->slsb.val[bufnr] != __state)
break;
@ -242,7 +233,7 @@ out:
static inline int get_buf_state(struct qdio_q *q, unsigned int bufnr,
unsigned char *state, int auto_ack)
{
return get_buf_states(q, bufnr, state, 1, auto_ack, 0);
return get_buf_states(q, bufnr, state, 1, auto_ack);
}
/* wrap-around safe setting of slsb states, returns number of changed buffers */
@ -464,7 +455,7 @@ static int get_inbound_buffer_frontier(struct qdio_q *q, unsigned int start,
* No siga sync here, as a PCI or we after a thin interrupt
* already sync'ed the queues.
*/
count = get_buf_states(q, start, &state, count, 1, 0);
count = get_buf_states(q, start, &state, count, 1);
if (!count)
return 0;
@ -541,7 +532,6 @@ static inline unsigned long qdio_aob_for_buffer(struct qdio_output_q *q,
WARN_ON_ONCE(phys_aob & 0xFF);
}
q->sbal_state[bufnr].flags = 0;
return phys_aob;
}
@ -554,19 +544,6 @@ static inline int qdio_tasklet_schedule(struct qdio_q *q)
return -EPERM;
}
static void qdio_check_pending(struct qdio_q *q, unsigned int index)
{
unsigned char state;
if (get_buf_state(q, index, &state, 0) > 0 &&
state == SLSB_P_OUTPUT_PENDING &&
q->u.out.aobs[index]) {
q->u.out.sbal_state[index].flags |=
QDIO_OUTBUF_STATE_FLAG_PENDING;
q->u.out.aobs[index] = NULL;
}
}
static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start,
unsigned int *error)
{
@ -587,7 +564,7 @@ static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start,
if (!count)
return 0;
count = get_buf_states(q, start, &state, count, 0, q->u.out.use_cq);
count = get_buf_states(q, start, &state, count, 0);
if (!count)
return 0;
@ -609,6 +586,9 @@ static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start,
account_sbals(q, count);
return count;
case SLSB_P_OUTPUT_ERROR:
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out error:%1d %02x",
q->nr, count);
*error = QDIO_ERROR_SLSB_STATE;
process_buffer_error(q, start, count);
atomic_sub(count, &q->nr_buf_used);
@ -640,27 +620,6 @@ static inline int qdio_outbound_q_done(struct qdio_q *q)
return atomic_read(&q->nr_buf_used) == 0;
}
static inline int qdio_outbound_q_moved(struct qdio_q *q, unsigned int start,
unsigned int *error)
{
int count;
count = get_outbound_buffer_frontier(q, start, error);
if (count) {
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out moved:%1d", q->nr);
if (q->u.out.use_cq && *error != QDIO_ERROR_SLSB_PENDING) {
unsigned int i;
for (i = 0; i < count; i++)
qdio_check_pending(q, QDIO_BUFNR(start + i));
}
}
return count;
}
static int qdio_kick_outbound_q(struct qdio_q *q, unsigned int count,
unsigned long aob)
{
@ -715,7 +674,7 @@ void qdio_outbound_tasklet(struct tasklet_struct *t)
qperf_inc(q, tasklet_outbound);
WARN_ON_ONCE(atomic_read(&q->nr_buf_used) < 0);
count = qdio_outbound_q_moved(q, start, &error);
count = get_outbound_buffer_frontier(q, start, &error);
if (count) {
q->first_to_check = add_buf(start, count);
@ -1482,7 +1441,7 @@ static int __qdio_inspect_queue(struct qdio_q *q, unsigned int *bufnr,
*error = 0;
count = q->is_input_q ? get_inbound_buffer_frontier(q, start, error) :
qdio_outbound_q_moved(q, start, error);
get_outbound_buffer_frontier(q, start, error);
if (count == 0)
return 0;

4
drivers/s390/net/qeth_core_main.c
View File

@ -6076,9 +6076,7 @@ static void qeth_iqd_tx_complete(struct qeth_qdio_out_q *queue,
struct qeth_card *card = queue->card;
bool error = !!qdio_error;
if ((qdio_error == QDIO_ERROR_SLSB_PENDING) ||
(queue->bufstates && (queue->bufstates[bidx].flags &
QDIO_OUTBUF_STATE_FLAG_PENDING))) {
if (qdio_error == QDIO_ERROR_SLSB_PENDING) {
WARN_ON_ONCE(card->options.cq != QETH_CQ_ENABLED);
QETH_CARD_TEXT_(card, 5, "pel%u", bidx);