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Date:   Tue, 2 Feb 2021 18:04:41 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Ben Widawsky <ben.widawsky@intel.com>
Cc:     linux-cxl@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org,
        linux-pci@vger.kernel.org, Bjorn Helgaas <helgaas@kernel.org>,
        Chris Browy <cbrowy@avery-design.com>,
        Christoph Hellwig <hch@infradead.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Jon Masters <jcm@jonmasters.org>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Rafael Wysocki <rafael.j.wysocki@intel.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        Vishal Verma <vishal.l.verma@intel.com>,
        daniel.lll@alibaba-inc.com,
        "John Groves (jgroves)" <jgroves@micron.com>,
        "Kelley, Sean V" <sean.v.kelley@intel.com>
Subject: Re: [PATCH 02/14] cxl/mem: Map memory device registers
Message-ID: <20210202180441.GC3708021@infradead.org>
References: <20210130002438.1872527-1-ben.widawsky@intel.com>
 <20210130002438.1872527-3-ben.widawsky@intel.com>
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In-Reply-To: <20210130002438.1872527-3-ben.widawsky@intel.com>
Precedence: bulk

Any reason not to merge a bunch of patches?  Both this one and
the previous one are rather useless on their own, making review
harder than necessary.

> + * cxl_mem_create() - Create a new &struct cxl_mem.
> + * @pdev: The pci device associated with the new &struct cxl_mem.
> + * @reg_lo: Lower 32b of the register locator
> + * @reg_hi: Upper 32b of the register locator.
> + *
> + * Return: The new &struct cxl_mem on success, NULL on failure.
> + *
> + * Map the BAR for a CXL memory device. This BAR has the memory device's
> + * registers for the device as specified in CXL specification.
> + */

A lot of text with almost no value over just reading the function.
What's that fetish with kerneldoc comments for trivial static functions?

> +		reg_type =
> +			(reg_lo >> CXL_REGLOC_RBI_SHIFT) & CXL_REGLOC_RBI_MASK;

OTOH this screams for a helper that would make the code a lot more
self documenting.

> +		if (reg_type == CXL_REGLOC_RBI_MEMDEV) {
> +			rc = 0;
> +			cxlm = cxl_mem_create(pdev, reg_lo, reg_hi);
> +			if (!cxlm)
> +				rc = -ENODEV;
> +			break;

And given that we're going to grow more types eventually, why not start
out with a switch here?  Also why return the structure when nothing
uses it?