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Subject: Re: [PATCH 2/7] lightnvm: pblk: fix mapping issue on failed writes
To:     hans.ml.holmberg@owltronix.com
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        javier@cnexlabs.com, hans.holmberg@cnexlabs.com
References: <1535545414-550-1-git-send-email-hans.ml.holmberg@owltronix.com>
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From:   =?UTF-8?Q?Matias_Bj=c3=b8rling?= <mb@lightnvm.io>
Message-ID: <eb5ca95c-6c4a-71a0-4cf1-634b211b52ce@lightnvm.io>
Date:   Wed, 29 Aug 2018 15:23:45 +0200
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On 08/29/2018 02:23 PM, Hans Holmberg wrote:
> From: Hans Holmberg <hans.holmberg@cnexlabs.com>
> 
> On 1.2-devices, the mapping-out of remaning sectors in the
> failed-write's block can result in an infinite loop,
> stalling the write pipeline, fix this.
> 
> Fixes: 6a3abf5beef6 ("lightnvm: pblk: rework write error recovery path")
> 
> Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com>
> ---
>   drivers/lightnvm/pblk-write.c | 45 ++++++++++++++++++++++++++++++++++---------
>   1 file changed, 36 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/lightnvm/pblk-write.c b/drivers/lightnvm/pblk-write.c
> index 1bc879ab679d..fd67325f6e54 100644
> --- a/drivers/lightnvm/pblk-write.c
> +++ b/drivers/lightnvm/pblk-write.c
> @@ -103,6 +103,41 @@ static void pblk_complete_write(struct pblk *pblk, struct nvm_rq *rqd,
>   	pblk_rb_sync_end(&pblk->rwb, &flags);
>   }
>   
> +static int pblk_next_ppa_in_blk(struct nvm_geo *geo, struct ppa_addr *ppa)
> +{
> +	int done = 0;

Could this please be renamed to last to signify it is the last ppa in 
the ppa.

> +
> +	if (geo->version == NVM_OCSSD_SPEC_12) {
> +		int sec = ppa->g.sec;
> +
> +		sec++;
> +		if (sec == geo->ws_min) {
> +			int pg = ppa->g.pg;
> +
> +			sec = 0;
> +			pg++;
> +			if (pg == geo->num_pg) {
> +				int pl = ppa->g.pl;
> +
> +				pg = 0;
> +				pl++;
> +				if (pl == geo->num_pln)
> +					done = 1;
> +
> +				ppa->g.pl = pl;
> +			}
> +			ppa->g.pg = pg;
> +		}
> +		ppa->g.sec = sec;
> +	} else {
> +		ppa->m.sec++;
> +		if (ppa->m.sec == geo->clba)
> +			done = 1;
> +	}
> +
> +	return done;
> +}
> +

Can you please move this function to core? I want to avoid introducing 
more if's around 1.2/2.0 in targets.

>   /* Map remaining sectors in chunk, starting from ppa */
>   static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
>   {
> @@ -125,15 +160,7 @@ static void pblk_map_remaining(struct pblk *pblk, struct ppa_addr *ppa)
>   		if (!test_and_set_bit(paddr, line->invalid_bitmap))
>   			le32_add_cpu(line->vsc, -1);
>   
> -		if (geo->version == NVM_OCSSD_SPEC_12) {
> -			map_ppa.ppa++;
> -			if (map_ppa.g.pg == geo->num_pg)
> -				done = 1;
> -		} else {
> -			map_ppa.m.sec++;
> -			if (map_ppa.m.sec == geo->clba)
> -				done = 1;
> -		}
> +		done = pblk_next_ppa_in_blk(geo, &map_ppa);
>   	}
>   
>   	line->w_err_gc->has_write_err = 1;
>