From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [net RFC] net/mlx4_en: Use frag stride in crossing page boundary
 condition
Date: Thu, 14 Jun 2018 12:12:16 -0700
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On 06/14/2018 11:56 AM, Saeed Mahameed wrote:

> Interestingly for this exact frag_stride we don't have an issue :)
> since it goes through a different condition branch
> (the page flipping thing):
> 
> if (frag_info->frag_stride == PAGE_SIZE / 2) {
>     frags->page_offset ^= PAGE_SIZE / 2;
> 	release = page_count(page) != 1 ||
> 		  page_is_pfmemalloc(page) ||
> 		  page_to_nid(page) != numa_mem_id();
> 

I guess you forgot to test on PowerPC where PAGE_SIZE=65536 ?

On PowerPC, the first branch is never taken.