diff options
| -rw-r--r-- | drivers/hv/ring_buffer.c | 55 | ||||
| -rw-r--r-- | 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 8f518af3074d..dd255c9b9420 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 40fd608475f7..eb7c0b215ba4 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 */ |