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-rw-r--r--drivers/hv/ring_buffer.c11
1 files changed, 10 insertions, 1 deletions
diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 71efacb90965..3d215d9dec43 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -439,7 +439,16 @@ int hv_ringbuffer_read(struct vmbus_channel *channel,
static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi)
{
u32 priv_read_loc = rbi->priv_read_index;
- u32 write_loc = READ_ONCE(rbi->ring_buffer->write_index);
+ u32 write_loc;
+
+ /*
+ * The Hyper-V host writes the packet data, then uses
+ * store_release() to update the write_index. Use load_acquire()
+ * here to prevent loads of the packet data from being re-ordered
+ * before the read of the write_index and potentially getting
+ * stale data.
+ */
+ write_loc = virt_load_acquire(&rbi->ring_buffer->write_index);
if (write_loc >= priv_read_loc)
return write_loc - priv_read_loc;