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) {