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Date:   Fri, 9 Jun 2023 12:08:52 +0100
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     "Verma, Vishal L" <vishal.l.verma@intel.com>
CC:     "Jiang, Dave" <dave.jiang@intel.com>,
        "Schofield, Alison" <alison.schofield@intel.com>,
        "linux-cxl@vger.kernel.org" <linux-cxl@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "Williams, Dan J" <dan.j.williams@intel.com>,
        "Weight, Russell H" <russell.h.weight@intel.com>,
        "bwidawsk@kernel.org" <bwidawsk@kernel.org>,
        "Weiny, Ira" <ira.weiny@intel.com>,
        "dave@stgolabs.net" <dave@stgolabs.net>
Subject: Re: [PATCH v2 1/4] cxl: add a firmware update mechanism using the
 sysfs firmware loader
Message-ID: <20230609120852.00003c6c@Huawei.com>
In-Reply-To: <298ed811de7148da70609ac2c6ef81f025690620.camel@intel.com>
References: <20230602-vv-fw_update-v2-0-e9e5cd5adb44@intel.com>
        <20230602-vv-fw_update-v2-1-e9e5cd5adb44@intel.com>
        <20230608154905.00007551@Huawei.com>
        <6666972e336a6749f24ce3aab7dddad63a796974.camel@intel.com>
        <298ed811de7148da70609ac2c6ef81f025690620.camel@intel.com>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Thu, 8 Jun 2023 20:26:43 +0000
"Verma, Vishal L" <vishal.l.verma@intel.com> wrote:

> On Thu, 2023-06-08 at 20:15 +0000, Verma, Vishal L wrote:
> >   
> > > > +
> > > > +???????fwl = firmware_upload_register(THIS_MODULE, &cxlmd->dev,
> > > > +????????????????????????????????????? dev_name(&cxlmd->dev),
> > > > +????????????????????????????????????? &cxl_memdev_fw_ops, cxlds);
> > > > +???????if (IS_ERR(fwl)) {
> > > > +???????????????dev_err(&cxlmd->dev, "Failed to register firmware loader\n");
> > > > +???????????????return PTR_ERR(fwl);  
> > > 
> > > It's called from probe only so could use dev_err_probe() for slight
> > > simplification.  
> > 
> > From what I can tell, this ends up looking like:
> > 
> > ????????fwl = firmware_upload_register(THIS_MODULE, dev, dev_name(dev),
> > ?????????????????????????????????????? &cxl_memdev_fw_ops, cxlds);
> > ????????rc = dev_err_probe(dev, PTR_ERR(fwl),
> > ?????????????????????????? "Failed to register firmware loader\n");
> > ????????if (rc)
> > ????????????????return rc;
> > 
> > Is that what you meant? Happy to make the change if so.
> > 
> >   
> Actually I can't drop the IS_ERR() check - so unless I'm missing
> something, this doesn't look like much of a simplification:
> 
> 
> 	if (IS_ERR(fwl)) {
> 		rc = dev_err_probe(dev, PTR_ERR(fwl),
> 				   "Failed to register firmware loader\n");
> 		if (rc)
> 			return rc;
> 	}
> 

Ah. I replied to previous. It's simpler than that as you know rc != 0 as
it's IS_ERR(fwl)

dev_err_probe() does two helpful things over dev_err()
1. Handles stashing the debug messages for the deferred probe cases (not
   relevant here but harmless)
2. Returns the variable you pass in as second argument to allow
   return dev_err_probe()


Jonathan