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Message-Id: <1459645191-25290-5-git-send-email-kys@microsoft.com>
Date: Sat, 2 Apr 2016 17:59:50 -0700
From: "K. Y. Srinivasan" <kys@...rosoft.com>
To: gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
devel@...uxdriverproject.org, olaf@...fle.de, apw@...onical.com,
vkuznets@...hat.com, jasowang@...hat.com
Cc: "K. Y. Srinivasan" <kys@...rosoft.com>
Subject: [PATCH 5/6] Drivers: hv: vmbus: Move some ring buffer functions to hyperv.h
In preparation for implementing APIs for in-place consumption of VMBUS
packets, movve some ring buffer functionality into hyperv.h
Signed-off-by: K. Y. Srinivasan <kys@...rosoft.com>
---
drivers/hv/ring_buffer.c | 55 ----------------------------------------------
include/linux/hyperv.h | 54 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+), 55 deletions(-)
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 8f518af..dd255c9 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -84,52 +84,6 @@ static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi)
return false;
}
-/*
- * To optimize the flow management on the send-side,
- * when the sender is blocked because of lack of
- * sufficient space in the ring buffer, potential the
- * consumer of the ring buffer can signal the producer.
- * This is controlled by the following parameters:
- *
- * 1. pending_send_sz: This is the size in bytes that the
- * producer is trying to send.
- * 2. The feature bit feat_pending_send_sz set to indicate if
- * the consumer of the ring will signal when the ring
- * state transitions from being full to a state where
- * there is room for the producer to send the pending packet.
- */
-
-static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
-{
- u32 cur_write_sz;
- u32 pending_sz;
-
- /*
- * Issue a full memory barrier before making the signaling decision.
- * Here is the reason for having this barrier:
- * If the reading of the pend_sz (in this function)
- * were to be reordered and read before we commit the new read
- * index (in the calling function) we could
- * have a problem. If the host were to set the pending_sz after we
- * have sampled pending_sz and go to sleep before we commit the
- * read index, we could miss sending the interrupt. Issue a full
- * memory barrier to address this.
- */
- virt_mb();
-
- pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz);
- /* If the other end is not blocked on write don't bother. */
- if (pending_sz == 0)
- return false;
-
- cur_write_sz = hv_get_bytes_to_write(rbi);
-
- if (cur_write_sz >= pending_sz)
- return true;
-
- return false;
-}
-
/* Get the next write location for the specified ring buffer. */
static inline u32
hv_get_next_write_location(struct hv_ring_buffer_info *ring_info)
@@ -180,15 +134,6 @@ hv_set_next_read_location(struct hv_ring_buffer_info *ring_info,
ring_info->ring_buffer->read_index = next_read_location;
}
-
-/* Get the start of the ring buffer. */
-static inline void *
-hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info)
-{
- return (void *)ring_info->ring_buffer->buffer;
-}
-
-
/* Get the size of the ring buffer. */
static inline u32
hv_get_ring_buffersize(struct hv_ring_buffer_info *ring_info)
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 4adeb6e..6797a30 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1366,4 +1366,58 @@ extern __u32 vmbus_proto_version;
int vmbus_send_tl_connect_request(const uuid_le *shv_guest_servie_id,
const uuid_le *shv_host_servie_id);
void vmbus_set_event(struct vmbus_channel *channel);
+
+/* Get the start of the ring buffer. */
+static inline void *
+hv_get_ring_buffer(struct hv_ring_buffer_info *ring_info)
+{
+ return (void *)ring_info->ring_buffer->buffer;
+}
+
+/*
+ * To optimize the flow management on the send-side,
+ * when the sender is blocked because of lack of
+ * sufficient space in the ring buffer, potential the
+ * consumer of the ring buffer can signal the producer.
+ * This is controlled by the following parameters:
+ *
+ * 1. pending_send_sz: This is the size in bytes that the
+ * producer is trying to send.
+ * 2. The feature bit feat_pending_send_sz set to indicate if
+ * the consumer of the ring will signal when the ring
+ * state transitions from being full to a state where
+ * there is room for the producer to send the pending packet.
+ */
+
+static inline bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi)
+{
+ u32 cur_write_sz;
+ u32 pending_sz;
+
+ /*
+ * Issue a full memory barrier before making the signaling decision.
+ * Here is the reason for having this barrier:
+ * If the reading of the pend_sz (in this function)
+ * were to be reordered and read before we commit the new read
+ * index (in the calling function) we could
+ * have a problem. If the host were to set the pending_sz after we
+ * have sampled pending_sz and go to sleep before we commit the
+ * read index, we could miss sending the interrupt. Issue a full
+ * memory barrier to address this.
+ */
+ virt_mb();
+
+ pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz);
+ /* If the other end is not blocked on write don't bother. */
+ if (pending_sz == 0)
+ return false;
+
+ cur_write_sz = hv_get_bytes_to_write(rbi);
+
+ if (cur_write_sz >= pending_sz)
+ return true;
+
+ return false;
+}
+
#endif /* _HYPERV_H */
--
1.7.4.1
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