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s390/qdio: let drivers opt-out from Output Queue scanning 

If a driver wants to use the new Output Queue poll code, then the qdio
layer must disable its internal Queue scanning. Let the driver select
this mode by passing a special scan_threshold of 0.

As the scan_threshold is the same for all Output Queues, also move it
into the main qdio_irq struct. This allows for fast opt-out checking, a
driver is expected to operate either _all_ or none of its Output Queues
in polling mode.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Julian Wiedmann 2019-08-23 11:48:48 +02:00 committed by David S. Miller
parent 7c47f5afde
commit 313dc689b1
4 changed files with 11 additions and 7 deletions
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2
arch/s390/include/asm/qdio.h
View File

@ -359,7 +359,7 @@ struct qdio_initialize {
qdio_handler_t *output_handler;
void (**queue_start_poll_array) (struct ccw_device *, int,
unsigned long);
int scan_threshold;
unsigned int scan_threshold;
unsigned long int_parm;
struct qdio_buffer **input_sbal_addr_array;
struct qdio_buffer **output_sbal_addr_array;

3
drivers/s390/cio/qdio.h
View File

@ -206,8 +206,6 @@ struct qdio_output_q {
struct qdio_outbuf_state *sbal_state;
/* timer to check for more outbound work */
struct timer_list timer;
/* used SBALs before tasklet schedule */
int scan_threshold;
};
/*
@ -295,6 +293,7 @@ struct qdio_irq {
struct qdio_ssqd_desc ssqd_desc;
void (*orig_handler) (struct ccw_device *, unsigned long, struct irb *);
unsigned int scan_threshold; /* used SBALs before tasklet schedule */
int perf_stat_enabled;
struct qdr *qdr;

11
drivers/s390/cio/qdio_main.c
View File

@ -880,7 +880,7 @@ static inline void qdio_check_outbound_pci_queues(struct qdio_irq *irq)
struct qdio_q *out;
int i;
if (!pci_out_supported(irq))
if (!pci_out_supported(irq) || !irq->scan_threshold)
return;
for_each_output_queue(irq, out, i)
@ -973,7 +973,7 @@ static void qdio_int_handler_pci(struct qdio_irq *irq_ptr)
}
}
if (!pci_out_supported(irq_ptr))
if (!pci_out_supported(irq_ptr) || !irq_ptr->scan_threshold)
return;
for_each_output_queue(irq_ptr, q, i) {
@ -1528,6 +1528,7 @@ static int handle_inbound(struct qdio_q *q, unsigned int callflags,
static int handle_outbound(struct qdio_q *q, unsigned int callflags,
int bufnr, int count)
{
const unsigned int scan_threshold = q->irq_ptr->scan_threshold;
unsigned char state = 0;
int used, rc = 0;
@ -1566,8 +1567,12 @@ static int handle_outbound(struct qdio_q *q, unsigned int callflags,
rc = qdio_kick_outbound_q(q, 0);
}
/* Let drivers implement their own completion scanning: */
if (!scan_threshold)
return rc;
/* in case of SIGA errors we must process the error immediately */
if (used >= q->u.out.scan_threshold || rc)
if (used >= scan_threshold || rc)
qdio_tasklet_schedule(q);
else
/* free the SBALs in case of no further traffic */

2
drivers/s390/cio/qdio_setup.c
View File

@ -248,7 +248,6 @@ static void setup_queues(struct qdio_irq *irq_ptr,
output_sbal_state_array += QDIO_MAX_BUFFERS_PER_Q;
q->is_input_q = 0;
q->u.out.scan_threshold = qdio_init->scan_threshold;
setup_storage_lists(q, irq_ptr, output_sbal_array, i);
output_sbal_array += QDIO_MAX_BUFFERS_PER_Q;
@ -474,6 +473,7 @@ int qdio_setup_irq(struct qdio_initialize *init_data)
irq_ptr->nr_input_qs = init_data->no_input_qs;
irq_ptr->nr_output_qs = init_data->no_output_qs;
irq_ptr->cdev = init_data->cdev;
irq_ptr->scan_threshold = init_data->scan_threshold;
ccw_device_get_schid(irq_ptr->cdev, &irq_ptr->schid);
setup_queues(irq_ptr, init_data);