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Subject: Re: [PATCH v3 1/2] iommu - Enable debugfs exposure of the IOMMU
To:     "Hook, Gary" <ghook@amd.com>,
        "Mehta, Sohil" <sohil.mehta@intel.com>,
        "gary.hook@amd.com" <gary.hook@amd.com>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>
Cc:     "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
References: <152302042701.47565.17954813724758433858.stgit@sosxen2.amd.com>
 <152302066417.47565.4017200105445420643.stgit@sosxen2.amd.com>
 <1523663790.2747.4.camel@intel.com>
 <10e422dd-a3ca-8ecb-50fa-e7f131a55a12@amd.com>
From:   Robin Murphy <robin.murphy@arm.com>
Message-ID: <80b1e9e5-3048-391a-6d7d-adeeece1bf46@arm.com>
Date:   Tue, 17 Apr 2018 18:55:49 +0100
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On 17/04/18 18:36, Hook, Gary wrote:
> On 4/13/2018 7:55 PM, Mehta, Sohil wrote:
>> On Fri, 2018-04-06 at 08:17 -0500, Gary R Hook wrote:
>>> +struct dentry *iommu_debugfs_setup(void)
>>> +{
>>> +    if (!debugfs_initialized())
>>
>> This check is probably not needed.
> 
> Ah, so it isn't. Thank you.
> 
>>
>>> +        return NULL;
>>> +
>>> +    if (!iommu_debugfs_dir)
>>> +        iommu_debugfs_dir = debugfs_create_dir("iommu",
>>> NULL);
>>> +
>>> +    if (iommu_debugfs_dir)
>>> +        pr_warn("WARNING: IOMMU DEBUGFS SUPPORT HAS BEEN
>>> ENABLED IN THIS KERNEL\n");
>>> +
>>
>> As this gets called for each IOMMU, do you want to use pr_warn_once?
> 
> That works, yes.

Or I guess you could just roll the pr_warn() into the previous if() 
condition, i.e. only warn when the singleton debugfs_dir is actually 
created.

Robin.

> 
>>
>>> +    return iommu_debugfs_dir;
>>> +}
>>> +EXPORT_SYMBOL_GPL(iommu_debugfs_setup);
>>
>> -Sohil
>>
> 
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