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Subject: Re: [PATCH] mtd: fix size in mtd_info_user to support 64-bit
To:     Miquel Raynal <miquel.raynal@bootlin.com>
CC:     <richard@nod.at>, <vigneshr@ti.com>, <David.Woodhouse@intel.com>,
        <Artem.Bityutskiy@nokia.com>, <ext-adrian.hunter@nokia.com>,
        <linux-kernel@vger.kernel.org>, <linux-mtd@lists.infradead.org>,
        <linfeilong@huawei.com>
References: <20210708131359.21591-1-linmiaohe@huawei.com>
 <20210716010224.44582046@xps13>
From:   Miaohe Lin <linmiaohe@huawei.com>
Message-ID: <95e3d455-ccb1-0e22-ee83-78dc6ad8aab1@huawei.com>
Date:   Fri, 16 Jul 2021 09:42:19 +0800
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On 2021/7/16 7:02, Miquel Raynal wrote:
> Hi Miaohe,
> 
> Miaohe Lin <linmiaohe@huawei.com> wrote on Thu, 8 Jul 2021 21:13:59
> +0800:
> 
>> From: Feilong Lin <linfeilong@huawei.com>
>>
>> The size in struct mtd_info_user is 32-bit, which will cause errors
>> when obtaining the size of large-capacity MTD devices, such as TLC
>> NAND FLASH-2048Gb.
> 
> Besides the fact that such devices are far from being supported by the
> Linux kernel, this change would basically break userspace, it cannot
> enter as-is...
> 

I see. Many thanks for your reply! We're working with these large-capacity
MTD devices now, any suggestion to work around this?

Thanks again!

>> Fixes: 69423d99fc18 ("[MTD] update internal API to support 64-bit device size")
>> Signed-off-by: Feilong Lin <linfeilong@huawei.com>
>> ---
>>  include/uapi/mtd/mtd-abi.h | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/include/uapi/mtd/mtd-abi.h b/include/uapi/mtd/mtd-abi.h
>> index b869990c2db2..efe0b53b10c1 100644
>> --- a/include/uapi/mtd/mtd-abi.h
>> +++ b/include/uapi/mtd/mtd-abi.h
>> @@ -128,7 +128,7 @@ struct mtd_write_req {
>>  struct mtd_info_user {
>>  	__u8 type;
>>  	__u32 flags;
>> -	__u32 size;	/* Total size of the MTD */
>> +	__u64 size;	/* Total size of the MTD */
>>  	__u32 erasesize;
>>  	__u32 writesize;
>>  	__u32 oobsize;	/* Amount of OOB data per block (e.g. 16) */
> 
> Thanks,
> Miquèl
> .
>