Even if guest were compiled without SMP support, it could not assume that host wasn't. So switch to use mb() instead of smp_mb() to force memory barriers for UP guest. Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> --- drivers/hv/ring_buffer.c | 10 +++++----- drivers/hv/vmbus_drv.c | 2 +- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index d6fbb57..791f45d 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -32,7 +32,7 @@ void hv_begin_read(struct hv_ring_buffer_info *rbi) { rbi->ring_buffer->interrupt_mask = 1; - smp_mb(); + mb(); } u32 hv_end_read(struct hv_ring_buffer_info *rbi) @@ -41,7 +41,7 @@ u32 hv_end_read(struct hv_ring_buffer_info *rbi) u32 write; rbi->ring_buffer->interrupt_mask = 0; - smp_mb(); + mb(); /* * Now check to see if the ring buffer is still empty. @@ -71,7 +71,7 @@ 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) { - smp_mb(); + mb(); if (rbi->ring_buffer->interrupt_mask) return false; @@ -442,7 +442,7 @@ int hv_ringbuffer_write(struct hv_ring_buffer_info *outring_info, sizeof(u64)); /* Issue a full memory barrier before updating the write index */ - smp_mb(); + mb(); /* Now, update the write location */ hv_set_next_write_location(outring_info, next_write_location); @@ -549,7 +549,7 @@ int hv_ringbuffer_read(struct hv_ring_buffer_info *inring_info, void *buffer, /* Make sure all reads are done before we update the read index since */ /* the writer may start writing to the read area once the read index */ /*is updated */ - smp_mb(); + mb(); /* Update the read index */ hv_set_next_read_location(inring_info, next_read_location); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index bf421e0..4004e54 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -434,7 +434,7 @@ static void vmbus_on_msg_dpc(unsigned long data) * will not deliver any more messages since there is * no empty slot */ - smp_mb(); + mb(); if (msg->header.message_flags.msg_pending) { /* -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html