Re: [PATCH] mm: pagewalk: fix unused variable warning

From: John Hubbard <jhubbard@nvidia.com>
To: "Arnd Bergmann" <arnd@arndb.de>,
	"Jérôme Glisse" <jglisse@redhat.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Steven Price" <steven.price@arm.com>,
	"Stephen Rothwell" <sfr@canb.auug.org.au>
Cc: Albert Ou <aou@eecs.berkeley.edu>,
	Alexandre Ghiti <alex@ghiti.fr>,
	"Andy Lutomirski" <luto@kernel.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Borislav Petkov <bp@alien8.de>,
	Catalin Marinas <catalin.marinas@arm.com>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"David S. Miller" <davem@davemloft.net>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Ingo Molnar" <mingo@redhat.com>, James Hogan <jhogan@kernel.org>,
	James Morse <james.morse@arm.com>,
	"Liang, Kan" <kan.liang@linux.intel.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Palmer Dabbelt <palmer@sifive.com>,
	Paul Burton <paul.burton@mips.com>,
	Paul Mackerras <paulus@samba.org>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	Russell King <linux@armlinux.org.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Vineet Gupta <vgupta@synopsys.com>, Will Deacon <will@kernel.org>,
	Zong Li <zong.li@sifive.com>, Jason Gunthorpe <jgg@ziepe.ca>,
	Ralph Campbell <rcampbell@nvidia.com>, <linux-mm@kvack.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: pagewalk: fix unused variable warning
Date: Tue, 7 Jan 2020 13:00:05 -0800	[thread overview]
Message-ID: <06c40b1a-7843-032e-0fdd-595a3218a93b@nvidia.com> (raw)
In-Reply-To: <20200107204607.1533842-1-arnd@arndb.de>

On 1/7/20 12:45 PM, Arnd Bergmann wrote:
> One of the pagewalk patches introduced a harmless warning:
> 
> mm/hmm.c: In function 'hmm_vma_walk_pud':
> mm/hmm.c:478:9: error: unused variable 'pmdp' [-Werror=unused-variable]
>   pmd_t *pmdp;
>          ^~~~
> mm/hmm.c:477:30: error: unused variable 'next' [-Werror=unused-variable]
>   unsigned long addr = start, next;
>                               ^~~~
> 
> Remove both of the now-unused variables.
> 
> Fixes: cb4d03d5fb4c ("mm: pagewalk: add p4d_entry() and pgd_entry()")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  mm/hmm.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 

Reviewed-by: John Hubbard <jhubbard@nvidia.com>


thanks,
-- 
John Hubbard
NVIDIA

> diff --git a/mm/hmm.c b/mm/hmm.c
> index a71295e99968..72e5a6d9a417 100644
> --- a/mm/hmm.c
> +++ b/mm/hmm.c
> @@ -474,8 +474,7 @@ static int hmm_vma_walk_pud(pud_t *pudp, unsigned long start, unsigned long end,
>  {
>  	struct hmm_vma_walk *hmm_vma_walk = walk->private;
>  	struct hmm_range *range = hmm_vma_walk->range;
> -	unsigned long addr = start, next;
> -	pmd_t *pmdp;
> +	unsigned long addr = start;
>  	pud_t pud;
>  	int ret = 0;
>  	spinlock_t *ptl = pud_trans_huge_lock(pudp, walk->vma);
>