On Thu, Mar 02, 2023 at 09:28:09AM +0000, Ruifeng Wang wrote:
> > -----Original Message-----
> > From: Tyler Retzlaff <roret...@linux.microsoft.com>
> > Sent: Thursday, March 2, 2023 8:48 AM
> > To: dev@dpdk.org
> > Cc: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>;
> > tho...@monjalon.net; Tyler
> > Retzlaff <roret...@linux.microsoft.com>
> > Subject: [PATCH 11/17] net/iavf: use previous value atomic fetch operations
> >
> > Use __atomic_fetch_{add,and,or,sub,xor} instead of
> > __atomic_{add,and,or,sub,xor}_fetch
> > when we have no interest in the result of the operation.
> >
> > Reduces unnecessary codegen that provided the result of the atomic
> > operation that was not
> > used.
> >
> > Change brings closer alignment with atomics available in C11 standard and
> > will reduce
> > review effort when they are integrated.
> >
> > Signed-off-by: Tyler Retzlaff <roret...@linux.microsoft.com>
> > ---
> > drivers/net/iavf/iavf_vchnl.c | 6 +++---
> > 1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/iavf/iavf_vchnl.c b/drivers/net/iavf/iavf_vchnl.c
> > index
> > 9adaadb..73875d7 100644
> > --- a/drivers/net/iavf/iavf_vchnl.c
> > +++ b/drivers/net/iavf/iavf_vchnl.c
> > @@ -128,7 +128,7 @@ struct iavf_event_handler {
> > int err = pipe(handler->fd);
> > #endif
> > if (err != 0) {
> > - __atomic_sub_fetch(&handler->ndev, 1, __ATOMIC_RELAXED);
> > + __atomic_fetch_sub(&handler->ndev, 1, __ATOMIC_RELAXED);
> > return -1;
> > }
> >
> > @@ -137,7 +137,7 @@ struct iavf_event_handler {
> >
> > if (rte_ctrl_thread_create(&handler->tid, "iavf-event-thread",
> > NULL, iavf_dev_event_handle, NULL)) {
> > - __atomic_sub_fetch(&handler->ndev, 1, __ATOMIC_RELAXED);
> > + __atomic_fetch_sub(&handler->ndev, 1, __ATOMIC_RELAXED);
> > return -1;
> > }
> >
> > @@ -533,7 +533,7 @@ struct iavf_event_handler {
> > /* read message and it's expected one */
> > if (msg_opc == vf->pend_cmd) {
> > uint32_t cmd_count =
> > - __atomic_sub_fetch(&vf->pend_cmd_count,
> > + __atomic_fetch_sub(&vf->pend_cmd_count,
>
> It doesn't apply here. The return value is used.
> The rest of the series looks good to me.
oh, i was blind to the line wrapping. definitely not correct.
thanks for catching this, will submit v2 with it reverted.
>
> > 1, __ATOMIC_RELAXED);
> > if (cmd_count == 0)
> > _notify_cmd(vf, msg_ret);
> > --
> > 1.8.3.1
