linux-kernel - Re: [PATCH V2] mm/cma: cma_declare_contiguous: correct err handling

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Message-Id: <20190227153626.GF16901@rapoport-lnx>
Date:   Wed, 27 Feb 2019 17:36:26 +0200
From:   Mike Rapoport <rppt@...ux.ibm.com>
To:     Peng Fan <peng.fan@....com>
Cc:     "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "labbott@...hat.com" <labbott@...hat.com>,
        "iamjoonsoo.kim@....com" <iamjoonsoo.kim@....com>,
        "mhocko@...e.com" <mhocko@...e.com>,
        "vbabka@...e.cz" <vbabka@...e.cz>,
        "rppt@...ux.vnet.ibm.com" <rppt@...ux.vnet.ibm.com>,
        "m.szyprowski@...sung.com" <m.szyprowski@...sung.com>,
        "andreyknvl@...gle.com" <andreyknvl@...gle.com>,
        "catalin.marinas@....com" <catalin.marinas@....com>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "van.freenix@...il.com" <van.freenix@...il.com>
Subject: Re: [PATCH V2] mm/cma: cma_declare_contiguous: correct err handling

On Wed, Feb 27, 2019 at 02:34:55PM +0000, Peng Fan wrote:
> In case cma_init_reserved_mem failed, need to free the memblock allocated
> by memblock_reserve or memblock_alloc_range.
> 
> Quote Catalin's comments:
> https://lkml.org/lkml/2019/2/26/482
> Kmemleak is supposed to work with the memblock_{alloc,free} pair and it
> ignores the memblock_reserve() as a memblock_alloc() implementation
> detail. It is, however, tolerant to memblock_free() being called on
> a sub-range or just a different range from a previous memblock_alloc().
> So the original patch looks fine to me. FWIW:
> 
> Signed-off-by: Peng Fan <peng.fan@....com>
> Reviewed-by: Catalin Marinas <catalin.marinas@....com>

Reviewed-by: Mike Rapoport <rppt@...ux.ibm.com>

> ---
> 
> V2:
>  Per Mike's comments, add more information in commit log
>  Add R-B
> 
>  mm/cma.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/cma.c b/mm/cma.c
> index c7b39dd3b4f6..f4f3a8a57d86 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -353,12 +353,14 @@ int __init cma_declare_contiguous(phys_addr_t base,
>  
>  	ret = cma_init_reserved_mem(base, size, order_per_bit, name, res_cma);
>  	if (ret)
> -		goto err;
> +		goto free_mem;
>  
>  	pr_info("Reserved %ld MiB at %pa\n", (unsigned long)size / SZ_1M,
>  		&base);
>  	return 0;
>  
> +free_mem:
> +	memblock_free(base, size);
>  err:
>  	pr_err("Failed to reserve %ld MiB\n", (unsigned long)size / SZ_1M);
>  	return ret;
> -- 
> 2.16.4
> 

-- 
Sincerely yours,
Mike.