qdio: extend API to allow polling
Extend the qdio API to allow polling in the upper-layer driver. This
is needed by qeth to use NAPI.
To use the new interface the upper-layer driver must specify the
queue_start_poll(). This callback is used to signal the upper-layer
driver that is has initiative and must process the inbound queue by
calling qdio_get_next_buffers(). If the upper-layer driver wants to
stop polling it calls qdio_start_irq().
Since adapter interrupts are not completely stoppable qdio implements
a software bit QDIO_QUEUE_IRQS_DISABLED to safely disable interrupts for an
input queue.
The old interface is preserved and will be used as is by zfcp.
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h
index f0037ee..0f4ef87 100644
--- a/drivers/s390/cio/qdio.h
+++ b/drivers/s390/cio/qdio.h
@@ -208,6 +208,7 @@
unsigned int eqbs_partial;
unsigned int sqbs;
unsigned int sqbs_partial;
+ unsigned int int_discarded;
} ____cacheline_aligned;
struct qdio_queue_perf_stat {
@@ -222,6 +223,10 @@
unsigned int nr_sbal_total;
};
+enum qdio_queue_irq_states {
+ QDIO_QUEUE_IRQS_DISABLED,
+};
+
struct qdio_input_q {
/* input buffer acknowledgement flag */
int polling;
@@ -231,6 +236,10 @@
int ack_count;
/* last time of noticing incoming data */
u64 timestamp;
+ /* upper-layer polling flag */
+ unsigned long queue_irq_state;
+ /* callback to start upper-layer polling */
+ void (*queue_start_poll) (struct ccw_device *, int, unsigned long);
};
struct qdio_output_q {
@@ -399,6 +408,26 @@
#define sub_buf(bufnr, dec) \
((bufnr - dec) & QDIO_MAX_BUFFERS_MASK)
+#define queue_irqs_enabled(q) \
+ (test_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state) == 0)
+#define queue_irqs_disabled(q) \
+ (test_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state) != 0)
+
+#define TIQDIO_SHARED_IND 63
+
+/* device state change indicators */
+struct indicator_t {
+ u32 ind; /* u32 because of compare-and-swap performance */
+ atomic_t count; /* use count, 0 or 1 for non-shared indicators */
+};
+
+extern struct indicator_t *q_indicators;
+
+static inline int shared_ind(struct qdio_irq *irq_ptr)
+{
+ return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
+}
+
/* prototypes for thin interrupt */
void qdio_setup_thinint(struct qdio_irq *irq_ptr);
int qdio_establish_thinint(struct qdio_irq *irq_ptr);
diff --git a/drivers/s390/cio/qdio_debug.c b/drivers/s390/cio/qdio_debug.c
index 6ce83f5..28868e7 100644
--- a/drivers/s390/cio/qdio_debug.c
+++ b/drivers/s390/cio/qdio_debug.c
@@ -56,9 +56,16 @@
seq_printf(m, "DSCI: %d nr_used: %d\n",
*(u32 *)q->irq_ptr->dsci, atomic_read(&q->nr_buf_used));
- seq_printf(m, "ftc: %d last_move: %d\n", q->first_to_check, q->last_move);
- 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, "ftc: %d last_move: %d\n",
+ q->first_to_check, q->last_move);
+ 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, "IRQs disabled: %u\n",
+ test_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state));
+ }
seq_printf(m, "SBAL states:\n");
seq_printf(m, "|0 |8 |16 |24 |32 |40 |48 |56 63|\n");
@@ -113,22 +120,6 @@
return 0;
}
-static ssize_t qstat_seq_write(struct file *file, const char __user *buf,
- size_t count, loff_t *off)
-{
- struct seq_file *seq = file->private_data;
- struct qdio_q *q = seq->private;
-
- if (!q)
- return 0;
- if (q->is_input_q)
- xchg(q->irq_ptr->dsci, 1);
- local_bh_disable();
- tasklet_schedule(&q->tasklet);
- local_bh_enable();
- return count;
-}
-
static int qstat_seq_open(struct inode *inode, struct file *filp)
{
return single_open(filp, qstat_show,
@@ -139,7 +130,6 @@
.owner = THIS_MODULE,
.open = qstat_seq_open,
.read = seq_read,
- .write = qstat_seq_write,
.llseek = seq_lseek,
.release = single_release,
};
@@ -166,7 +156,8 @@
"QEBSM eqbs",
"QEBSM eqbs partial",
"QEBSM sqbs",
- "QEBSM sqbs partial"
+ "QEBSM sqbs partial",
+ "Discarded interrupts"
};
static int qperf_show(struct seq_file *m, void *v)
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 00520f9..5fcfa7f 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -884,8 +884,19 @@
if (unlikely(irq_ptr->state == QDIO_IRQ_STATE_STOPPED))
return;
- for_each_input_queue(irq_ptr, q, i)
- tasklet_schedule(&q->tasklet);
+ for_each_input_queue(irq_ptr, q, i) {
+ if (q->u.in.queue_start_poll) {
+ /* skip if polling is enabled or already in work */
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state)) {
+ qperf_inc(q, int_discarded);
+ continue;
+ }
+ q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
+ q->irq_ptr->int_parm);
+ } else
+ tasklet_schedule(&q->tasklet);
+ }
if (!(irq_ptr->qib.ac & QIB_AC_OUTBOUND_PCI_SUPPORTED))
return;
@@ -1519,6 +1530,129 @@
}
EXPORT_SYMBOL_GPL(do_QDIO);
+/**
+ * qdio_start_irq - process input buffers
+ * @cdev: associated ccw_device for the qdio subchannel
+ * @nr: input queue number
+ *
+ * Return codes
+ * 0 - success
+ * 1 - irqs not started since new data is available
+ */
+int qdio_start_irq(struct ccw_device *cdev, int nr)
+{
+ struct qdio_q *q;
+ struct qdio_irq *irq_ptr = cdev->private->qdio_data;
+
+ if (!irq_ptr)
+ return -ENODEV;
+ q = irq_ptr->input_qs[nr];
+
+ WARN_ON(queue_irqs_enabled(q));
+
+ if (!shared_ind(q->irq_ptr))
+ xchg(q->irq_ptr->dsci, 0);
+
+ qdio_stop_polling(q);
+ clear_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state);
+
+ /*
+ * We need to check again to not lose initiative after
+ * resetting the ACK state.
+ */
+ if (!shared_ind(q->irq_ptr) && *q->irq_ptr->dsci)
+ goto rescan;
+ if (!qdio_inbound_q_done(q))
+ goto rescan;
+ return 0;
+
+rescan:
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state))
+ return 0;
+ else
+ return 1;
+
+}
+EXPORT_SYMBOL(qdio_start_irq);
+
+/**
+ * qdio_get_next_buffers - process input buffers
+ * @cdev: associated ccw_device for the qdio subchannel
+ * @nr: input queue number
+ * @bufnr: first filled buffer number
+ * @error: buffers are in error state
+ *
+ * Return codes
+ * < 0 - error
+ * = 0 - no new buffers found
+ * > 0 - number of processed buffers
+ */
+int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr,
+ int *error)
+{
+ struct qdio_q *q;
+ int start, end;
+ struct qdio_irq *irq_ptr = cdev->private->qdio_data;
+
+ if (!irq_ptr)
+ return -ENODEV;
+ q = irq_ptr->input_qs[nr];
+ WARN_ON(queue_irqs_enabled(q));
+
+ qdio_sync_after_thinint(q);
+
+ /*
+ * The interrupt could be caused by a PCI request. Check the
+ * PCI capable outbound queues.
+ */
+ qdio_check_outbound_after_thinint(q);
+
+ if (!qdio_inbound_q_moved(q))
+ return 0;
+
+ /* Note: upper-layer MUST stop processing immediately here ... */
+ if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
+ return -EIO;
+
+ start = q->first_to_kick;
+ end = q->first_to_check;
+ *bufnr = start;
+ *error = q->qdio_error;
+
+ /* for the next time */
+ q->first_to_kick = end;
+ q->qdio_error = 0;
+ return sub_buf(end, start);
+}
+EXPORT_SYMBOL(qdio_get_next_buffers);
+
+/**
+ * qdio_stop_irq - disable interrupt processing for the device
+ * @cdev: associated ccw_device for the qdio subchannel
+ * @nr: input queue number
+ *
+ * Return codes
+ * 0 - interrupts were already disabled
+ * 1 - interrupts successfully disabled
+ */
+int qdio_stop_irq(struct ccw_device *cdev, int nr)
+{
+ struct qdio_q *q;
+ struct qdio_irq *irq_ptr = cdev->private->qdio_data;
+
+ if (!irq_ptr)
+ return -ENODEV;
+ q = irq_ptr->input_qs[nr];
+
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state))
+ return 0;
+ else
+ return 1;
+}
+EXPORT_SYMBOL(qdio_stop_irq);
+
static int __init init_QDIO(void)
{
int rc;
diff --git a/drivers/s390/cio/qdio_setup.c b/drivers/s390/cio/qdio_setup.c
index 34c7e40..a13cf7e 100644
--- a/drivers/s390/cio/qdio_setup.c
+++ b/drivers/s390/cio/qdio_setup.c
@@ -161,6 +161,7 @@
setup_queues_misc(q, irq_ptr, qdio_init->input_handler, i);
q->is_input_q = 1;
+ q->u.in.queue_start_poll = qdio_init->queue_start_poll;
setup_storage_lists(q, irq_ptr, input_sbal_array, i);
input_sbal_array += QDIO_MAX_BUFFERS_PER_Q;
diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c
index 8daf1b9..752dbee 100644
--- a/drivers/s390/cio/qdio_thinint.c
+++ b/drivers/s390/cio/qdio_thinint.c
@@ -25,24 +25,20 @@
*/
#define TIQDIO_NR_NONSHARED_IND 63
#define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
-#define TIQDIO_SHARED_IND 63
/* list of thin interrupt input queues */
static LIST_HEAD(tiq_list);
DEFINE_MUTEX(tiq_list_lock);
/* adapter local summary indicator */
-static unsigned char *tiqdio_alsi;
+static u8 *tiqdio_alsi;
-/* device state change indicators */
-struct indicator_t {
- u32 ind; /* u32 because of compare-and-swap performance */
- atomic_t count; /* use count, 0 or 1 for non-shared indicators */
-};
-static struct indicator_t *q_indicators;
+struct indicator_t *q_indicators;
static int css_qdio_omit_svs;
+static u64 last_ai_time;
+
static inline unsigned long do_clear_global_summary(void)
{
register unsigned long __fn asm("1") = 3;
@@ -116,59 +112,73 @@
}
}
-static inline int shared_ind(struct qdio_irq *irq_ptr)
+static inline int shared_ind_used(void)
{
- return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
+ return atomic_read(&q_indicators[TIQDIO_SHARED_IND].count);
}
/**
* tiqdio_thinint_handler - thin interrupt handler for qdio
- * @ind: pointer to adapter local summary indicator
- * @drv_data: NULL
+ * @alsi: pointer to adapter local summary indicator
+ * @data: NULL
*/
-static void tiqdio_thinint_handler(void *ind, void *drv_data)
+static void tiqdio_thinint_handler(void *alsi, void *data)
{
struct qdio_q *q;
+ last_ai_time = S390_lowcore.int_clock;
+
/*
* SVS only when needed: issue SVS to benefit from iqdio interrupt
- * avoidance (SVS clears adapter interrupt suppression overwrite)
+ * avoidance (SVS clears adapter interrupt suppression overwrite).
*/
if (!css_qdio_omit_svs)
do_clear_global_summary();
- /*
- * reset local summary indicator (tiqdio_alsi) to stop adapter
- * interrupts for now
- */
- xchg((u8 *)ind, 0);
+ /* reset local summary indicator */
+ if (shared_ind_used())
+ xchg(tiqdio_alsi, 0);
/* protect tiq_list entries, only changed in activate or shutdown */
rcu_read_lock();
/* check for work on all inbound thinint queues */
- list_for_each_entry_rcu(q, &tiq_list, entry)
- /* only process queues from changed sets */
- if (*q->irq_ptr->dsci) {
- qperf_inc(q, adapter_int);
+ list_for_each_entry_rcu(q, &tiq_list, entry) {
+ /* only process queues from changed sets */
+ if (!*q->irq_ptr->dsci)
+ continue;
+
+ if (q->u.in.queue_start_poll) {
+ /* skip if polling is enabled or already in work */
+ if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
+ &q->u.in.queue_irq_state)) {
+ qperf_inc(q, int_discarded);
+ continue;
+ }
+
+ /* avoid dsci clear here, done after processing */
+ q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
+ q->irq_ptr->int_parm);
+ } else {
/* only clear it if the indicator is non-shared */
if (!shared_ind(q->irq_ptr))
xchg(q->irq_ptr->dsci, 0);
/*
- * don't call inbound processing directly since
- * that could starve other thinint queues
+ * Call inbound processing but not directly
+ * since that could starve other thinint queues.
*/
tasklet_schedule(&q->tasklet);
}
-
+ qperf_inc(q, adapter_int);
+ }
rcu_read_unlock();
/*
- * if we used the shared indicator clear it now after all queues
- * were processed
+ * If the shared indicator was used clear it now after all queues
+ * were processed.
*/
- if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
+ if (shared_ind_used()) {
xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
/* prevent racing */
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index b263575..da54a28 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -277,16 +277,12 @@
static void zfcp_qdio_setup_init_data(struct qdio_initialize *id,
struct zfcp_qdio *qdio)
{
-
+ memset(id, 0, sizeof(*id));
id->cdev = qdio->adapter->ccw_device;
id->q_format = QDIO_ZFCP_QFMT;
memcpy(id->adapter_name, dev_name(&id->cdev->dev), 8);
ASCEBC(id->adapter_name, 8);
id->qib_rflags = QIB_RFLAGS_ENABLE_DATA_DIV;
- id->qib_param_field_format = 0;
- id->qib_param_field = NULL;
- id->input_slib_elements = NULL;
- id->output_slib_elements = NULL;
id->no_input_qs = 1;
id->no_output_qs = 1;
id->input_handler = zfcp_qdio_int_resp;