s390/qdio: consolidate index tracking for queue scan
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>
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 045f2aa..cfce255 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -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;
@@ -519,7 +518,6 @@ 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)
@@ -527,7 +525,6 @@ static int get_inbound_buffer_frontier(struct qdio_q *q)
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)
@@ -547,11 +544,11 @@ 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();
@@ -559,9 +556,8 @@ static int qdio_inbound_q_moved(struct qdio_q *q)
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))
@@ -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))
@@ -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);
}
@@ -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;
@@ -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);
@@ -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);
@@ -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))
@@ -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);
@@ -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;
@@ -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);
}
@@ -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;
@@ -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
@@ -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;