"K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> writes: > We need to issue a full memory barrier prior making a signalling > decision. Any reason this should be mb()? This is pretty strong and will probably lead to performace regression ... and, btw, we have another mb() in hv_ringbuffer_read(). Could you please describe the scenarion you're trying to protect against so we could search for a better solution? > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > --- > drivers/hv/ring_buffer.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c > index 2919395..67dc245 100644 > --- a/drivers/hv/ring_buffer.c > +++ b/drivers/hv/ring_buffer.c > @@ -104,6 +104,7 @@ static bool hv_need_to_signal_on_read(struct hv_ring_buffer_info *rbi) > u32 cur_write_sz; > u32 pending_sz; > > + 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) -- Vitaly -- 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