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Date: Mon, 1 May 2017 21:32:14 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Baoquan He <bhe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
        x86@kernel.org, Kees Cook <keescook@chromium.org>,
        Thomas Garnier <thgarnie@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Yasuaki Ishimatsu <yasu.isimatu@gmail.com>,
        Jinbum Park <jinb.park7@gmail.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Yinghai Lu <yinghai@kernel.org>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Young <dyoung@redhat.com>
Subject: Re: [PATCH v2] x86/mm: Fix incorrect for loop count calculation in
 sync_global_pgds
Message-ID: <20170501193214.fbozpx6dlrapsma3@gmail.com>
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* Baoquan He <bhe@redhat.com> wrote:

>  arch/x86/mm/init_64.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
> index 15173d3..dfa9edb 100644
> --- a/arch/x86/mm/init_64.c
> +++ b/arch/x86/mm/init_64.c
> @@ -96,7 +96,9 @@ void sync_global_pgds(unsigned long start, unsigned long end)
>  {
>  	unsigned long address;
>  
> -	for (address = start; address <= end; address += PGDIR_SIZE) {
> +	for (address = start; address <= end;
> +	     address = ALIGN(address + 1, PGDIR_SIZE)) {
> +
>  		const pgd_t *pgd_ref = pgd_offset_k(address);
>  		struct page *page;

This patch does not apply cleanly to tip:master.

You can avoid the col80 problems by renaming 'address' to the canonical 'addr' 
name, the loop will become:

	for (addr = start; addr <= end; addr = ALIGN(addr + 1, PGDIR_SIZE)) {

... which fits into 80 cols.

Thanks,

	Ingo