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| author | Neil Horman | 2015-08-01 00:56:32 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2015-08-04 02:45:02 +0200 |
| commit | fdc792cd1b5c86cb34770707aa1b04edce5288cf (patch) | |
| tree | 4a47e45329aa668ed914812fbfa7a15b9f20d011 /drivers/staging/unisys/visorbus/visorchannel.c | |
| parent | staging: android: Allow compile test of GPIO consumers if !GPIOLIB (diff) | |
| download | kernel-qcow2-linux-fdc792cd1b5c86cb34770707aa1b04edce5288cf.tar.gz kernel-qcow2-linux-fdc792cd1b5c86cb34770707aa1b04edce5288cf.tar.xz kernel-qcow2-linux-fdc792cd1b5c86cb34770707aa1b04edce5288cf.zip | |
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/visorbus/visorchannel.c')
| -rw-r--r-- | drivers/staging/unisys/visorbus/visorchannel.c | 21 |
1 files changed, 21 insertions, 0 deletions
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) { |