linux-kernel - Re: [PATCH v4] nvme: Add hardware monitoring support

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Message-ID: <20191105181023.GA22468@roeck-us.net>
Date:   Tue, 5 Nov 2019 10:10:23 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Akinobu Mita <akinobu.mita@...il.com>
Cc:     Keith Busch <kbusch@...nel.org>, Chris Healy <cphealy@...il.com>,
        Jens Axboe <axboe@...com>, Christoph Hellwig <hch@....de>,
        Sagi Grimberg <sagi@...mberg.me>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-nvme@...ts.infradead.org, Linux PM <linux-pm@...r.kernel.org>
Subject: Re: [PATCH v4] nvme: Add hardware monitoring support

On Wed, Nov 06, 2019 at 12:44:56AM +0900, Akinobu Mita wrote:
> 2019年11月6日(水) 0:38 Akinobu Mita <akinobu.mita@...il.com>:
> >
> > 2019年11月2日(土) 23:55 Guenter Roeck <linux@...ck-us.net>:
> > > diff --git a/drivers/nvme/host/nvme-hwmon.c b/drivers/nvme/host/nvme-hwmon.c
> > > new file mode 100644
> > > index 000000000000..28b4b7f43bb0
> > > --- /dev/null
> > > +++ b/drivers/nvme/host/nvme-hwmon.c
> > > @@ -0,0 +1,181 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +/*
> > > + * NVM Express hardware monitoring support
> > > + * Copyright (c) 2019, Guenter Roeck
> > > + */
> > > +
> > > +#include <linux/hwmon.h>
> > > +#include <asm/unaligned.h>
> > > +
> > > +#include "nvme.h"
> > > +
> > > +struct nvme_hwmon_data {
> > > +       struct nvme_ctrl *ctrl;
> > > +       struct nvme_smart_log log;
> > > +       struct mutex read_lock;
> > > +};
> > > +
> > > +static int nvme_hwmon_get_smart_log(struct nvme_hwmon_data *data)
> > > +{
> > > +       int ret;
> > > +
> > > +       ret = nvme_get_log(data->ctrl, NVME_NSID_ALL, NVME_LOG_SMART, 0,
> > > +                          &data->log, sizeof(data->log), 0);
> > > +
> > > +       return ret <= 0 ? ret : -EIO;
> > > +}
> > > +
> > > +static int nvme_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
> > > +                          u32 attr, int channel, long *val)
> > > +{
> > > +       struct nvme_hwmon_data *data = dev_get_drvdata(dev);
> > > +       struct nvme_smart_log *log = &data->log;
> > > +       int temp;
> > > +       int err;
> > > +
> > > +       /*
> > > +        * First handle attributes which don't require us to read
> > > +        * the smart log.
> > > +        */
> > > +       switch (attr) {
> > > +       case hwmon_temp_max:
> > > +               *val = (data->ctrl->wctemp - 273) * 1000;
> > > +               return 0;
> > > +       case hwmon_temp_crit:
> > > +               *val = (data->ctrl->cctemp - 273) * 1000;
> >
> > This attribute should be 'hwmon_temp_max_alarm' rather than
> > 'hwmon_temp_crit_alarm'?
> 

Yes, you are correct. Actually, re-reading the specification,
the bit may also be set for under-temperature alarms, so I'll
use the more generic hwmon_temp_alarm.

Thanks,
Guenter

> Oops, I misquoted the code.
> 
> This comment should be addressed to the code below:
> 
> +       case hwmon_temp_crit_alarm:
> +               *val = !!(log->critical_warning & NVME_SMART_CRIT_TEMPERATURE);
> +               break;