Re: [PATCH v2 1/2] lightnvm: pblk: Do not overwrite ppa list with meta list

["Matias Bjørling" <mb@lightnvm.io>]

On 12/07/2018 09:25 AM, Igor Konopko wrote:
> Currently when using PBLK with 0 sized metadata both ppa list
> and meta list points to the same memory since pblk_dma_meta_size()
> returns 0 in that case.
> 
> This commit fix that issue by ensuring that pblk_dma_meta_size()
> always returns space equal to sizeof(struct pblk_sec_meta) and thus
> ppa list and meta list points to different memory address.
> 
> Even that in that case drive does not really care about meta_list
> pointer, this is the easiest way to fix that issue without introducing
> changes in many places in the code just for 0 sized metadata case.
> 
> The same approach needs to be also done for pblk_get_sec_meta()
> since we also cannot point to the same memory address in meta buffer
> when we are using it for pblk recovery process
> 
> Reported-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com>
> ---
>   drivers/lightnvm/pblk.h | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk.h b/drivers/lightnvm/pblk.h
> index bc40b1381ff6..85e38ed62f85 100644
> --- a/drivers/lightnvm/pblk.h
> +++ b/drivers/lightnvm/pblk.h
> @@ -1388,12 +1388,15 @@ static inline unsigned int pblk_get_min_chks(struct pblk *pblk)
>   static inline struct pblk_sec_meta *pblk_get_meta(struct pblk *pblk,
>   							 void *meta, int index)
>   {
> -	return meta + pblk->oob_meta_size * index;
> +	return meta +
> +	       max_t(int, sizeof(struct pblk_sec_meta), pblk->oob_meta_size)
> +	       * index;
>   }
>   
>   static inline int pblk_dma_meta_size(struct pblk *pblk)
>   {
> -	return pblk->oob_meta_size * NVM_MAX_VLBA;
> +	return max_t(int, sizeof(struct pblk_sec_meta), pblk->oob_meta_size)
> +	       * NVM_MAX_VLBA;
>   }
>   
>   static inline int pblk_is_oob_meta_supported(struct pblk *pblk)
> 

Thanks Igor. It's applied for 4.21. I've updated the description a bit