Re: [PATCH v3] f2fs: deliver the accumulated 'issued' to __issue_discard_cmd_orderly() to meet the max_requests limit

[Chao Yu <chao@kernel.org>]

On 2022/12/13 17:34, Yuwei Guan wrote:
> Any of the following scenarios will send more than the number of
> max_requests at a time, which will not meet the design of the
> max_requests limit.
> 
> - Set max_ordered_discard larger than discard_granularity from userspace.
> - It is a small size device, discard_granularity can be tuned to 1 in
>    f2fs_tuning_parameters().
> 
> We need to deliver the accumulated @issued to __issue_discard_cmd_orderly()
> to meet the max_requests limit.
> 
> BTW, convert the parameter type of @issued in __submit_discard_cmd().
> 
> Signed-off-by: Yuwei Guan <Yuwei.Guan@zeekrlife.com>
> Cc: Bagas Sanjaya <bagasdotme@gmail.com>

For the code part, it looks good to me.

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

> ---
>   fs/f2fs/segment.c | 24 +++++++++++-------------
>   1 file changed, 11 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> index a9099a754dd2..5268938466f5 100644
> --- a/fs/f2fs/segment.c
> +++ b/fs/f2fs/segment.c
> @@ -1097,8 +1097,7 @@ static void __update_discard_tree_range(struct f2fs_sb_info *sbi,
>   /* this function is copied from blkdev_issue_discard from block/blk-lib.c */
>   static int __submit_discard_cmd(struct f2fs_sb_info *sbi,
>   						struct discard_policy *dpolicy,
> -						struct discard_cmd *dc,
> -						unsigned int *issued)
> +						struct discard_cmd *dc, int *issued)
>   {
>   	struct block_device *bdev = dc->bdev;
>   	unsigned int max_discard_blocks =
> @@ -1379,8 +1378,8 @@ static void __queue_discard_cmd(struct f2fs_sb_info *sbi,
>   	mutex_unlock(&SM_I(sbi)->dcc_info->cmd_lock);
>   }
>   
> -static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> -					struct discard_policy *dpolicy)
> +static void __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
> +					struct discard_policy *dpolicy, int *issued)
>   {
>   	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
>   	struct discard_cmd *prev_dc = NULL, *next_dc = NULL;
> @@ -1388,7 +1387,6 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
>   	struct discard_cmd *dc;
>   	struct blk_plug plug;
>   	unsigned int pos = dcc->next_pos;
> -	unsigned int issued = 0;
>   	bool io_interrupted = false;
>   
>   	mutex_lock(&dcc->cmd_lock);
> @@ -1415,9 +1413,9 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
>   		}
>   
>   		dcc->next_pos = dc->lstart + dc->len;
> -		err = __submit_discard_cmd(sbi, dpolicy, dc, &issued);
> +		err = __submit_discard_cmd(sbi, dpolicy, dc, issued);
>   
> -		if (issued >= dpolicy->max_requests)
> +		if (*issued >= dpolicy->max_requests)
>   			break;
>   next:
>   		node = rb_next(&dc->rb_node);
> @@ -1433,10 +1431,8 @@ static unsigned int __issue_discard_cmd_orderly(struct f2fs_sb_info *sbi,
>   
>   	mutex_unlock(&dcc->cmd_lock);
>   
> -	if (!issued && io_interrupted)
> -		issued = -1;
> -
> -	return issued;
> +	if (!(*issued) && io_interrupted)
> +		*issued = -1;
>   }
>   static unsigned int __wait_all_discard_cmd(struct f2fs_sb_info *sbi,
>   					struct discard_policy *dpolicy);
> @@ -1464,8 +1460,10 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
>   		if (i + 1 < dpolicy->granularity)
>   			break;
>   
> -		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered)
> -			return __issue_discard_cmd_orderly(sbi, dpolicy);
> +		if (i + 1 < dcc->max_ordered_discard && dpolicy->ordered) {
> +			__issue_discard_cmd_orderly(sbi, dpolicy, &issued);
> +			return issued;
> +		}
>   
>   		pend_list = &dcc->pend_list[i];
>