Re: [PATCH v2] lightnvm: pblk: consider max hw sectors supported for max_write_pgs

["Matias Bjørling" <mb@lightnvm.io>]

On 10/05/2018 07:39 PM, Zhoujie Wu wrote:
> When do GC, the number of read/write sectors are determined
> by max_write_pgs(see gc_rq preparation in pblk_gc_line_prepare_ws).
> 
> Due to max_write_pgs doesn't consider max hw sectors
> supported by nvme controller(128K), which leads to GC
> tries to read 64 * 4K in one command, and see below error
> caused by pblk_bio_map_addr in function pblk_submit_read_gc.
> 
> [ 2923.005376] pblk: could not add page to bio
> [ 2923.005377] pblk: could not allocate GC bio (18446744073709551604)
> 
> Signed-off-by: Zhoujie Wu <zjwu@marvell.com>
> ---
> v2: Changed according to Javier's comments.
> Remove unneccessary comment and move the definition of bqueue to
> maintain ordering.
> 
>   drivers/lightnvm/pblk-init.c | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/lightnvm/pblk-init.c b/drivers/lightnvm/pblk-init.c
> index e357388..0ef9ac5 100644
> --- a/drivers/lightnvm/pblk-init.c
> +++ b/drivers/lightnvm/pblk-init.c
> @@ -391,6 +391,7 @@ static void pblk_put_global_caches(void)
>   static int pblk_core_init(struct pblk *pblk)
>   {
>   	struct nvm_tgt_dev *dev = pblk->dev;
> +	struct request_queue *bqueue = dev->q;
>   	struct nvm_geo *geo = &dev->geo;
>   	int ret, max_write_ppas;
>   
> @@ -407,6 +408,8 @@ static int pblk_core_init(struct pblk *pblk)
>   	pblk->min_write_pgs = geo->ws_opt;
>   	max_write_ppas = pblk->min_write_pgs * geo->all_luns;
>   	pblk->max_write_pgs = min_t(int, max_write_ppas, NVM_MAX_VLBA);
> +	pblk->max_write_pgs =  min_t(int, pblk->max_write_pgs,
> +		queue_max_hw_sectors(bqueue) / (geo->csecs >> 9));
>   	pblk_set_sec_per_write(pblk, pblk->min_write_pgs);
>   
>   	pblk->pad_dist = kcalloc(pblk->min_write_pgs - 1, sizeof(atomic64_t),
> 

Thanks Zhoujie. I've done the following update and applied it to 4.20. 
Note that I also removed the bqueue.

-       pblk->max_write_pgs =  min_t(int, pblk->max_write_pgs,
-               queue_max_hw_sectors(bqueue) / (geo->csecs >> 9));
+       pblk->max_write_pgs = min_t(int, pblk->max_write_pgs,
+               queue_max_hw_sectors(dev->q) / (geo->csecs >> 
SECTOR_SHIFT));

Javier, I've carried over your Reviewed-by, let me know if you want it 
to be removed.