Skip to content

Commit

Permalink
s390/qdio: consolidate index tracking for queue scan
Browse files Browse the repository at this point in the history 
qdio.ko offers a small number of high-level functions to drive the
scanning of a QDIO queue for ready-to-process SBALs:
qdio_get_next_buffers(), __[ti]qdio_inbound_processing() and
__qdio_outbound_processing().

Let each of those functions maintain the 'start' index for their current
scan, and pass it to lower-level helpers as needed. This improves the
code's overall layering, and allows us to eliminate the additional
first_to_kick cursor with a follow-on patch.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Jens Remus <jremus@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
  • Loading branch information
Julian Wiedmann authored and Martin Schwidefsky committed Apr 18, 2019
1 parent 5b2ad27 commit 6bcf74e
Showing 1 changed file with 31 additions and 24 deletions.
55 changes: 31 additions & 24 deletions drivers/s390/cio/qdio_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -492,9 +492,8 @@ static inline void inbound_primed(struct qdio_q *q, unsigned int start,
set_buf_states(q, start, SLSB_P_INPUT_NOT_INIT, count);
}

static int get_inbound_buffer_frontier(struct qdio_q *q)
static int get_inbound_buffer_frontier(struct qdio_q *q, unsigned int start)
{
unsigned int start = q->first_to_check;
unsigned char state = 0;
int count;

Expand All @@ -519,15 +518,13 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
switch (state) {
case SLSB_P_INPUT_PRIMED:
inbound_primed(q, start, count);
q->first_to_check = add_buf(start, count);
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:
process_buffer_error(q, start, count);
q->first_to_check = add_buf(start, count);
if (atomic_sub_return(count, &q->nr_buf_used) == 0)
qperf_inc(q, inbound_queue_full);
if (q->irq_ptr->perf_stat_enabled)
Expand All @@ -547,21 +544,20 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
}
}

static int qdio_inbound_q_moved(struct qdio_q *q)
static int qdio_inbound_q_moved(struct qdio_q *q, unsigned int start)
{
int count;

count = get_inbound_buffer_frontier(q);
count = get_inbound_buffer_frontier(q, start);

if (count && !is_thinint_irq(q->irq_ptr) && MACHINE_IS_LPAR)
q->u.in.timestamp = get_tod_clock();

return count;
}

static inline int qdio_inbound_q_done(struct qdio_q *q)
static inline int qdio_inbound_q_done(struct qdio_q *q, unsigned int start)
{
unsigned int start = q->first_to_check;
unsigned char state = 0;

if (!atomic_read(&q->nr_buf_used))
Expand Down Expand Up @@ -672,17 +668,20 @@ static inline int qdio_tasklet_schedule(struct qdio_q *q)

static void __qdio_inbound_processing(struct qdio_q *q)
{
unsigned int start = q->first_to_check;
int count;

qperf_inc(q, tasklet_inbound);

count = qdio_inbound_q_moved(q);
count = qdio_inbound_q_moved(q, start);
if (count == 0)
return;

start = add_buf(start, count);
q->first_to_check = start;
qdio_kick_handler(q, count);

if (!qdio_inbound_q_done(q)) {
if (!qdio_inbound_q_done(q, start)) {
/* means poll time is not yet over */
qperf_inc(q, tasklet_inbound_resched);
if (!qdio_tasklet_schedule(q))
Expand All @@ -694,7 +693,7 @@ static void __qdio_inbound_processing(struct qdio_q *q)
* We need to check again to not lose initiative after
* resetting the ACK state.
*/
if (!qdio_inbound_q_done(q)) {
if (!qdio_inbound_q_done(q, start)) {
qperf_inc(q, tasklet_inbound_resched2);
qdio_tasklet_schedule(q);
}
Expand All @@ -706,9 +705,8 @@ void qdio_inbound_processing(unsigned long data)
__qdio_inbound_processing(q);
}

static int get_outbound_buffer_frontier(struct qdio_q *q)
static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start)
{
unsigned int start = q->first_to_check;
unsigned char state = 0;
int count;

Expand Down Expand Up @@ -740,13 +738,11 @@ static int get_outbound_buffer_frontier(struct qdio_q *q)
"out empty:%1d %02x", q->nr, count);

atomic_sub(count, &q->nr_buf_used);
q->first_to_check = add_buf(start, count);
if (q->irq_ptr->perf_stat_enabled)
account_sbals(q, count);
return count;
case SLSB_P_OUTPUT_ERROR:
process_buffer_error(q, start, count);
q->first_to_check = add_buf(start, count);
atomic_sub(count, &q->nr_buf_used);
if (q->irq_ptr->perf_stat_enabled)
account_sbals_error(q, count);
Expand All @@ -773,11 +769,11 @@ 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)
static inline int qdio_outbound_q_moved(struct qdio_q *q, unsigned int start)
{
int count;

count = get_outbound_buffer_frontier(q);
count = get_outbound_buffer_frontier(q, start);

if (count)
DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out moved:%1d", q->nr);
Expand Down Expand Up @@ -829,14 +825,17 @@ static int qdio_kick_outbound_q(struct qdio_q *q, unsigned long aob)

static void __qdio_outbound_processing(struct qdio_q *q)
{
unsigned int start = q->first_to_check;
int count;

qperf_inc(q, tasklet_outbound);
WARN_ON_ONCE(atomic_read(&q->nr_buf_used) < 0);

count = qdio_outbound_q_moved(q);
if (count)
count = qdio_outbound_q_moved(q, start);
if (count) {
q->first_to_check = add_buf(start, count);
qdio_kick_handler(q, count);
}

if (queue_type(q) == QDIO_ZFCP_QFMT && !pci_out_supported(q->irq_ptr) &&
!qdio_outbound_q_done(q))
Expand Down Expand Up @@ -891,6 +890,7 @@ static inline void qdio_check_outbound_pci_queues(struct qdio_irq *irq)

static void __tiqdio_inbound_processing(struct qdio_q *q)
{
unsigned int start = q->first_to_check;
int count;

qperf_inc(q, tasklet_inbound);
Expand All @@ -900,13 +900,15 @@ static void __tiqdio_inbound_processing(struct qdio_q *q)
/* The interrupt could be caused by a PCI request: */
qdio_check_outbound_pci_queues(q->irq_ptr);

count = qdio_inbound_q_moved(q);
count = qdio_inbound_q_moved(q, start);
if (count == 0)
return;

start = add_buf(start, count);
q->first_to_check = start;
qdio_kick_handler(q, count);

if (!qdio_inbound_q_done(q)) {
if (!qdio_inbound_q_done(q, start)) {
qperf_inc(q, tasklet_inbound_resched);
if (!qdio_tasklet_schedule(q))
return;
Expand All @@ -917,7 +919,7 @@ static void __tiqdio_inbound_processing(struct qdio_q *q)
* We need to check again to not lose initiative after
* resetting the ACK state.
*/
if (!qdio_inbound_q_done(q)) {
if (!qdio_inbound_q_done(q, start)) {
qperf_inc(q, tasklet_inbound_resched2);
qdio_tasklet_schedule(q);
}
Expand Down Expand Up @@ -1637,7 +1639,7 @@ int qdio_start_irq(struct ccw_device *cdev, int nr)
*/
if (test_nonshared_ind(irq_ptr))
goto rescan;
if (!qdio_inbound_q_done(q))
if (!qdio_inbound_q_done(q, q->first_to_check))
goto rescan;
return 0;

Expand Down Expand Up @@ -1668,11 +1670,13 @@ int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr,
{
struct qdio_q *q;
struct qdio_irq *irq_ptr = cdev->private->qdio_data;
unsigned int start;
int count;

if (!irq_ptr)
return -ENODEV;
q = irq_ptr->input_qs[nr];
start = q->first_to_check;

/*
* Cannot rely on automatic sync after interrupt since queues may
Expand All @@ -1683,10 +1687,13 @@ int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr,

qdio_check_outbound_pci_queues(irq_ptr);

count = qdio_inbound_q_moved(q);
count = qdio_inbound_q_moved(q, start);
if (count == 0)
return 0;

start = add_buf(start, count);
q->first_to_check = start;

/* Note: upper-layer MUST stop processing immediately here ... */
if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
return -EIO;
Expand Down

0 comments on commit 6bcf74e

Please sign in to comment.