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From:   "Huang, Ying" <ying.huang@intel.com>
To:     Miaoqian Lin <linmq006@gmail.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Wei Xu <weixugc@google.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/demotion: Fix NULL vs IS_ERR checking in
 memory_tier_init
References: <20221110030751.1627266-1-linmq006@gmail.com>
Date:   Thu, 10 Nov 2022 11:09:34 +0800
In-Reply-To: <20221110030751.1627266-1-linmq006@gmail.com> (Miaoqian Lin's
        message of "Thu, 10 Nov 2022 07:07:51 +0400")
Message-ID: <874jv7wln5.fsf@yhuang6-desk2.ccr.corp.intel.com>
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Miaoqian Lin <linmq006@gmail.com> writes:

> The alloc_memory_type() function return error pointers on error
> instead of NULL.
> Use IS_ERR() to check the return value to fix this.
>
> Fixes: 7b88bda3761b ("mm/demotion/dax/kmem: set node's abstract distance to MEMTIER_DEFAULT_DAX_ADISTANCE")
> Signed-off-by: Miaoqian Lin <linmq006@gmail.com>

Thanks!

Reviewed-by: "Huang, Ying" <ying.huang@intel.com>

> ---
>  mm/memory-tiers.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
> index fa8c9d07f9ce..ac0dae9e54bf 100644
> --- a/mm/memory-tiers.c
> +++ b/mm/memory-tiers.c
> @@ -645,7 +645,7 @@ static int __init memory_tier_init(void)
>  	 * than default DRAM tier.
>  	 */
>  	default_dram_type = alloc_memory_type(MEMTIER_ADISTANCE_DRAM);
> -	if (!default_dram_type)
> +	if (IS_ERR(default_dram_type))
>  		panic("%s() failed to allocate default DRAM tier\n", __func__);
>  
>  	/*