diff options
Diffstat (limited to 'drivers/hv/ring_buffer.c')
| -rw-r--r-- | drivers/hv/ring_buffer.c | 95 |
1 files changed, 12 insertions, 83 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index a40a73a7b71d..fe586bf74e17 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -33,25 +33,21 @@ void hv_begin_read(struct hv_ring_buffer_info *rbi) { rbi->ring_buffer->interrupt_mask = 1; - mb(); + virt_mb(); } u32 hv_end_read(struct hv_ring_buffer_info *rbi) { - u32 read; - u32 write; rbi->ring_buffer->interrupt_mask = 0; - mb(); + virt_mb(); /* * Now check to see if the ring buffer is still empty. * If it is not, we raced and we need to process new * incoming messages. */ - hv_get_ringbuffer_availbytes(rbi, &read, &write); - - return read; + return hv_get_bytes_to_read(rbi); } /* @@ -72,69 +68,17 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi) static bool hv_need_to_signal(u32 old_write, struct hv_ring_buffer_info *rbi) { - mb(); - if (rbi->ring_buffer->interrupt_mask) + virt_mb(); + if (READ_ONCE(rbi->ring_buffer->interrupt_mask)) return false; /* check interrupt_mask before read_index */ - rmb(); + virt_rmb(); /* * This is the only case we need to signal when the * ring transitions from being empty to non-empty. */ - if (old_write == rbi->ring_buffer->read_index) - return true; - - 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 r_size; - u32 write_loc; - u32 read_loc = rbi->ring_buffer->read_index; - 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. - */ - mb(); - - pending_sz = rbi->ring_buffer->pending_send_sz; - write_loc = rbi->ring_buffer->write_index; - /* If the other end is not blocked on write don't bother. */ - if (pending_sz == 0) - return false; - - r_size = rbi->ring_datasize; - cur_write_sz = write_loc >= read_loc ? r_size - (write_loc - read_loc) : - read_loc - write_loc; - - if (cur_write_sz >= pending_sz) + if (old_write == READ_ONCE(rbi->ring_buffer->read_index)) return true; return false; @@ -188,17 +132,9 @@ hv_set_next_read_location(struct hv_ring_buffer_info *ring_info, u32 next_read_location) { ring_info->ring_buffer->read_index = next_read_location; + ring_info->priv_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) @@ -332,7 +268,6 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, { int i = 0; u32 bytes_avail_towrite; - u32 bytes_avail_toread; u32 totalbytes_towrite = 0; u32 next_write_location; @@ -348,9 +283,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, if (lock) spin_lock_irqsave(&outring_info->ring_lock, flags); - hv_get_ringbuffer_availbytes(outring_info, - &bytes_avail_toread, - &bytes_avail_towrite); + bytes_avail_towrite = hv_get_bytes_to_write(outring_info); /* * If there is only room for the packet, assume it is full. @@ -384,7 +317,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, sizeof(u64)); /* Issue a full memory barrier before updating the write index */ - mb(); + virt_mb(); /* Now, update the write location */ hv_set_next_write_location(outring_info, next_write_location); @@ -401,7 +334,6 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, u32 buflen, u32 *buffer_actual_len, u64 *requestid, bool *signal, bool raw) { - u32 bytes_avail_towrite; u32 bytes_avail_toread; u32 next_read_location = 0; u64 prev_indices = 0; @@ -417,10 +349,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, *buffer_actual_len = 0; *requestid = 0; - hv_get_ringbuffer_availbytes(inring_info, - &bytes_avail_toread, - &bytes_avail_towrite); - + bytes_avail_toread = hv_get_bytes_to_read(inring_info); /* Make sure there is something to read */ if (bytes_avail_toread < sizeof(desc)) { /* @@ -464,7 +393,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, * the writer may start writing to the read area once the read index * is updated. */ - mb(); + virt_mb(); /* Update the read index */ hv_set_next_read_location(inring_info, next_read_location); |