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Subject: Re: [PATCH V2 2/3] perf/x86/intel/uncore: Record the size of mapped
 area
To:     Andi Kleen <ak@linux.intel.com>
Cc:     peterz@infradead.org, mingo@redhat.com,
        linux-kernel@vger.kernel.org, David.Laight@aculab.com
References: <1590671727-99311-1-git-send-email-kan.liang@linux.intel.com>
 <1590671727-99311-2-git-send-email-kan.liang@linux.intel.com>
 <20200528132908.GG611145@tassilo.jf.intel.com>
From:   "Liang, Kan" <kan.liang@linux.intel.com>
Message-ID: <7d593433-0e7d-afb5-0bf3-4ea6cd5ad352@linux.intel.com>
Date:   Thu, 28 May 2020 09:44:45 -0400
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On 5/28/2020 9:29 AM, Andi Kleen wrote:
> On Thu, May 28, 2020 at 06:15:26AM -0700, kan.liang@linux.intel.com wrote:
>> -	box->io_addr = ioremap(addr, SNB_UNCORE_PCI_IMC_MAP_SIZE);
>> +	if (!type->mmio_map_size) {
>> +		pr_warn("perf uncore: Cannot ioremap for %s. Size of map area is 0.\n",
>> +			type->name);
>> +		return;
>> +	}
> 
> Is that likely that the size is 0?

In case someone forgets to set mmio_map_size.

> 
> In any case you have to test the return value of ioremap. So I would rather
> test the address for 0 than the size.

The box->io_addr is checked now, but there is no warning message.
I will remove the check for mmio_map_size, and add a warning message for 
the check of box->io_addr.

Thanks,
Kan