ubi: some invalid code in the function scan_peb

[Zhihao Cheng]

在 2023/10/18 15:28, Ryder Wang 写道:
> The patch below can remove the invalid code. It can pass ubi code build and ubi attach can also be OK from the testing.
> 

Reviewed-by: Zhihao Cheng <chengzhihao1 at huawei.com>

> diff --git a/drivers/mtd/ubi/attach.c b/drivers/mtd/ubi/attach.c
> index 10b2459f8951..8268ca6a91d1
> --- a/drivers/mtd/ubi/attach.c
> +++ b/drivers/mtd/ubi/attach.c
> @@ -995,28 +995,6 @@ static int scan_peb(struct ubi_device *ubi, struct ubi_attach_info *ai,
>        if (!ec_err) {
>              int image_seq;
>   
> -           /* Make sure UBI version is OK */
> -           if (ech->version != UBI_VERSION) {
> -                 ubi_err(ubi, "this UBI version is %d, image version is %d",
> -                       UBI_VERSION, (int)ech->version);
> -                 return -EINVAL;
> -           }
> -
> -           ec = be64_to_cpu(ech->ec);
> -           if (ec > UBI_MAX_ERASECOUNTER) {
> -                 /*
> -                  * Erase counter overflow. The EC headers have 64 bits
> -                  * reserved, but we anyway make use of only 31 bit
> -                  * values, as this seems to be enough for any existing
> -                  * flash. Upgrade UBI and use 64-bit erase counters
> -                  * internally.
> -                  */
> -                 ubi_err(ubi, "erase counter overflow, max is %d",
> -                       UBI_MAX_ERASECOUNTER);
> -                 ubi_dump_ec_hdr(ech);
> -                 return -EINVAL;
> -           }
> -
>              /*
>               * Make sure that all PEBs have the same image sequence number.
>               * This allows us to detect situations when users flash UBI
> 
> 
> From: Zhihao Cheng <chengzhihao1 at huawei.com>
> Sent: Wednesday, October 18, 2023 14:31
> To: Ryder Wang <rydercoding at hotmail.com>; linux-mtd at lists.infradead.org <linux-mtd at lists.infradead.org>
> Subject: Re: ubi: some invalid code in the function scan_peb
>   
> 在 2023/10/18 13:59, Ryder Wang 写道:
>> I just find some dead code in the function scan_peb in drvier/mtd/ubi/attach.c.
>>
>> In the function scan_peb, it calls validate_ec_hdr which calls validate_ec_hdr. If ubi version or erase count is incorrect, it will report -EINVAL and abort the function scan_peb. However, ubi version or erase count will be checked again in scan_peb and such check code will never find the errors because such errors should have been detected by validate_ec_hdr (aborting).
>>
> 
> Yes, redundant checking indeed exists in scan_peb(), could you send a
> patch to clean it up?
>