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Subject: Re: [PATCH v3 11/12] mm/gup_benchmark: support pin_user_pages() and
 related calls
To:     "Kirill A. Shutemov" <kirill@shutemov.name>
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References: <20200201034029.4063170-1-jhubbard@nvidia.com>
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From:   John Hubbard <jhubbard@nvidia.com>
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On 2/3/20 5:58 AM, Kirill A. Shutemov wrote:
...
>> @@ -19,6 +21,48 @@ struct gup_benchmark {
>>  	__u64 expansion[10];	/* For future use */
>>  };
>>  
>> +static void put_back_pages(unsigned int cmd, struct page **pages,
>> +			   unsigned long nr_pages)
>> +{
>> +	int i;
>> +
>> +	switch (cmd) {
>> +	case GUP_FAST_BENCHMARK:
>> +	case GUP_LONGTERM_BENCHMARK:
>> +	case GUP_BENCHMARK:
>> +		for (i = 0; i < nr_pages; i++)
> 
> 'i' is 'int' and 'nr_pages' is 'unsigned long'.
> There's space for trouble :P
> 

Yes, I've changed it to "unsigned int", thanks.

>> +			put_page(pages[i]);
>> +		break;
>> +
>> +	case PIN_FAST_BENCHMARK:
>> +	case PIN_BENCHMARK:
>> +		unpin_user_pages(pages, nr_pages);
>> +		break;
>> +	}
>> +}
>> +
>> +static void verify_dma_pinned(unsigned int cmd, struct page **pages,
>> +			      unsigned long nr_pages)
>> +{
>> +	int i;
>> +	struct page *page;
>> +
>> +	switch (cmd) {
>> +	case PIN_FAST_BENCHMARK:
>> +	case PIN_BENCHMARK:
>> +		for (i = 0; i < nr_pages; i++) {
> 
> Ditto.
> 

Fixed here also.


>> +			page = pages[i];
>> +			if (WARN(!page_maybe_dma_pinned(page),
>> +				 "pages[%d] is NOT dma-pinned\n", i)) {

...and changed to "pages[%u]", to match.


thanks,
-- 
John Hubbard
NVIDIA


>> +
>> +				dump_page(page, "gup_benchmark failure");
>> +				break;
>> +			}
>> +		}
>> +		break;
>> +	}
>> +}
>> +
>>  static int __gup_benchmark_ioctl(unsigned int cmd,
>>  		struct gup_benchmark *gup)
>>  {
>