diff options
| -rw-r--r-- | drivers/hv/ring_buffer.c | 32 | ||||
| -rw-r--r-- | include/linux/hyperv.h | 49 |
2 files changed, 30 insertions, 51 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index f29981764653..a9021f13379f 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -29,6 +29,7 @@ #include <linux/uio.h> #include <linux/vmalloc.h> #include <linux/slab.h> +#include <linux/prefetch.h> #include "hyperv_vmbus.h" @@ -357,7 +358,7 @@ struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; - /* set state for later hv_signal_on_read() */ + /* set state for later hv_pkt_iter_close */ rbi->cached_read_index = rbi->ring_buffer->read_index; if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor)) @@ -400,6 +401,8 @@ EXPORT_SYMBOL_GPL(__hv_pkt_iter_next); void hv_pkt_iter_close(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; + u32 cur_write_sz, cached_write_sz; + u32 pending_sz; /* * Make sure all reads are done before we update the read index since @@ -409,6 +412,31 @@ void hv_pkt_iter_close(struct vmbus_channel *channel) virt_rmb(); rbi->ring_buffer->read_index = rbi->priv_read_index; - hv_signal_on_read(channel); + /* + * 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; + + cur_write_sz = hv_get_bytes_to_write(rbi); + + if (cur_write_sz < pending_sz) + return; + + cached_write_sz = hv_get_cached_bytes_to_write(rbi); + if (cached_write_sz < pending_sz) + vmbus_setevent(channel); } EXPORT_SYMBOL_GPL(hv_pkt_iter_close); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 5e5f966bf37f..308e1f9706bb 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1472,55 +1472,6 @@ hv_get_ring_buffer(const struct hv_ring_buffer_info *ring_info) } /* - * 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 void hv_signal_on_read(struct vmbus_channel *channel) -{ - u32 cur_write_sz, cached_write_sz; - u32 pending_sz; - struct hv_ring_buffer_info *rbi = &channel->inbound; - - /* - * 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; - - cur_write_sz = hv_get_bytes_to_write(rbi); - - if (cur_write_sz < pending_sz) - return; - - cached_write_sz = hv_get_cached_bytes_to_write(rbi); - if (cached_write_sz < pending_sz) - vmbus_setevent(channel); -} - -/* * Mask off host interrupt callback notifications */ static inline void hv_begin_read(struct hv_ring_buffer_info *rbi) |