linux-kernel - Re: [PATCH] nvme: Remove redundant validation in nvme_start

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Message-ID: <20200714032352.GA111285@VM20190228-100.tbsite.net>
Date:   Tue, 14 Jul 2020 11:23:52 +0800
From:   Baolin Wang <baolin.wang@...ux.alibaba.com>
To:     Chaitanya Kulkarni <Chaitanya.Kulkarni@....com>
Cc:     "kbusch@...nel.org" <kbusch@...nel.org>,
        "axboe@...com" <axboe@...com>, "hch@....de" <hch@....de>,
        "sagi@...mberg.me" <sagi@...mberg.me>,
        "baolin.wang7@...il.com" <baolin.wang7@...il.com>,
        "linux-nvme@...ts.infradead.org" <linux-nvme@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] nvme: Remove redundant validation in nvme_start_ctrl()

On Mon, Jul 13, 2020 at 11:58:18PM +0000, Chaitanya Kulkarni wrote:
> On 7/12/20 23:31, Baolin Wang wrote:
> > We've already validated the 'kato' in nvme_start_keep_alive(), thus no
> > need to validate it again in nvme_start_ctrl(). Remove it.
> > 
> > Signed-off-by: Baolin Wang <baolin.wang@...ux.alibaba.com>
> > ---
> >   drivers/nvme/host/core.c | 3 +--
> >   1 file changed, 1 insertion(+), 2 deletions(-)
> > 
> > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> > index 3d00ea4..a95e26e 100644
> > --- a/drivers/nvme/host/core.c
> > +++ b/drivers/nvme/host/core.c
> > @@ -4313,8 +4313,7 @@ void nvme_stop_ctrl(struct nvme_ctrl *ctrl)
> >   
> >   void nvme_start_ctrl(struct nvme_ctrl *ctrl)
> >   {
> > -	if (ctrl->kato)
> > -		nvme_start_keep_alive(ctrl);
> > +	nvme_start_keep_alive(ctrl);
> >   
> >   	nvme_enable_aen(ctrl);
> >   
> > 
> 
> Since start keep alive is so small to make a function call how about we 
> in-line the call ? untested patch :-

I am Okay about your suggestion. Will send v2 with your suggested-by tag
if no other objection. Thanks.

> 
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 09abf2ca33f5..c7289c23658a 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -4311,8 +4311,9 @@ EXPORT_SYMBOL_GPL(nvme_stop_ctrl);
> 
>   void nvme_start_ctrl(struct nvme_ctrl *ctrl)
>   {
> +       /* if ctrl keep alive time out is set start keep alive */
>          if (ctrl->kato)
> -               nvme_start_keep_alive(ctrl);
> +               queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * 
> HZ);
> 
>          nvme_enable_aen(ctrl);
> 
> root@...ring nvme (xarray) # git diff
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index 09abf2ca33f5..08e1a6826b08 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1031,14 +1031,6 @@ static void nvme_keep_alive_work(struct 
> work_struct *work)
>          }
>   }
> 
> -static void nvme_start_keep_alive(struct nvme_ctrl *ctrl)
> -{
> -       if (unlikely(ctrl->kato == 0))
> -               return;
> -
> -       queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);
> -}
> -
>   void nvme_stop_keep_alive(struct nvme_ctrl *ctrl)
>   {
>          if (unlikely(ctrl->kato == 0))
> @@ -4311,8 +4303,9 @@ EXPORT_SYMBOL_GPL(nvme_stop_ctrl);
> 
>   void nvme_start_ctrl(struct nvme_ctrl *ctrl)
>   {
> +       /* if ctrl keep alive time out is set start keep alive */
>          if (ctrl->kato)
> -               nvme_start_keep_alive(ctrl);
> +               queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * 
> HZ);
> 
>          nvme_enable_aen(ctrl);
> 
>