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authorJulian Wiedmann <jwi@linux.ibm.com>2019-08-23 11:48:48 +0200
committerDavid S. Miller <davem@davemloft.net>2019-08-24 16:39:18 -0700
commit313dc689b16c08b081939ee9b87dac3736c780e3 (patch)
tree473f175b8e96dd7f404e10872d2353ce4e895838 /drivers/s390/cio/qdio_main.c
parents390/qdio: enable drivers to poll for Output completions (diff)
downloadlinux-dev-313dc689b16c08b081939ee9b87dac3736c780e3.tar.xz
linux-dev-313dc689b16c08b081939ee9b87dac3736c780e3.zip
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>
Diffstat (limited to '')
-rw-r--r--drivers/s390/cio/qdio_main.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 5efba0d29190..5b63c505a2f7 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -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 @@ set:
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 */