diff options
| author | Neil Horman <nhorman@redhat.com> | 2015-08-01 01:56:32 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-08-04 03:45:02 +0300 |
| commit | fdc792cd1b5c86cb34770707aa1b04edce5288cf (patch) | |
| tree | 4a47e45329aa668ed914812fbfa7a15b9f20d011 /drivers/staging/unisys | |
| parent | fd93b8059294146a1c3dc9cf6b5616c22b7b47f7 (diff) | |
| download | linux-fdc792cd1b5c86cb34770707aa1b04edce5288cf.tar.xz | |
staging: unisys: visorchannel: Add peek function
According to unisys, the s_par hypervisor has a bug in which it never
triggers an interrupt. That makes the visornic effectively a 2ms poll
loop. In order to just have the rx thread shceduling a napi poll every
2ms, lets instead give it the chance to check the response queue for
data before we schedule. This helper provides that functionality
Signed-off-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/unisys')
| -rw-r--r-- | drivers/staging/unisys/include/visorbus.h | 2 | ||||
| -rw-r--r-- | drivers/staging/unisys/visorbus/visorchannel.c | 21 |
2 files changed, 23 insertions, 0 deletions
diff --git a/drivers/staging/unisys/include/visorbus.h b/drivers/staging/unisys/include/visorbus.h index a0144c6a8ad1..9235536fa75f 100644 --- a/drivers/staging/unisys/include/visorbus.h +++ b/drivers/staging/unisys/include/visorbus.h @@ -201,6 +201,8 @@ bool visorchannel_signalremove(struct visorchannel *channel, u32 queue, void *msg); bool visorchannel_signalinsert(struct visorchannel *channel, u32 queue, void *msg); +bool visorchannel_signalempty(struct visorchannel *channel, u32 queue); + int visorchannel_signalqueue_slots_avail(struct visorchannel *channel, u32 queue); int visorchannel_signalqueue_max_slots(struct visorchannel *channel, u32 queue); diff --git a/drivers/staging/unisys/visorbus/visorchannel.c b/drivers/staging/unisys/visorbus/visorchannel.c index 242246492b7a..6da7e49a6627 100644 --- a/drivers/staging/unisys/visorbus/visorchannel.c +++ b/drivers/staging/unisys/visorbus/visorchannel.c @@ -430,6 +430,27 @@ visorchannel_signalremove(struct visorchannel *channel, u32 queue, void *msg) } EXPORT_SYMBOL_GPL(visorchannel_signalremove); +bool +visorchannel_signalempty(struct visorchannel *channel, u32 queue) +{ + unsigned long flags = 0; + struct signal_queue_header sig_hdr; + bool rc = false; + + if (channel->needs_lock) + spin_lock_irqsave(&channel->remove_lock, flags); + + if (!sig_read_header(channel, queue, &sig_hdr)) + rc = true; + if (sig_hdr.head == sig_hdr.tail) + rc = true; + if (channel->needs_lock) + spin_unlock_irqrestore(&channel->remove_lock, flags); + + return rc; +} +EXPORT_SYMBOL_GPL(visorchannel_signalempty); + static bool signalinsert_inner(struct visorchannel *channel, u32 queue, void *msg) { |