linux-kernel - Re: [PATCH v3 1/4] block/badblocks: change some members of badblocks to bool

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Date:   Wed, 21 Jun 2023 07:02:30 -0700
From:   Ashok Raj <ashok_raj@...ux.intel.com>
To:     linan666@...weicloud.com
Cc:     axboe@...nel.dk, linan122@...wei.com, dan.j.williams@...el.com,
        vishal.l.verma@...el.com, linux-block@...r.kernel.org,
        linux-kernel@...r.kernel.org, yukuai3@...wei.com,
        yi.zhang@...wei.com, houtao1@...wei.com, yangerkun@...wei.com,
        Ashok Raj <ashok.raj@...el.com>
Subject: Re: [PATCH v3 1/4] block/badblocks: change some members of badblocks
 to bool

On Thu, Jun 22, 2023 at 01:20:49AM +0800, linan666@...weicloud.com wrote:
> From: Li Nan <linan122@...wei.com>
> 
> "changed" and "unacked_exist" are used as boolean type. Change the type
> of them to bool. And reorder fields to reduce memory hole.

minor nit: If you use a .gitorderfile to list .h before .c it will help review them in
order.

I don't know if its even worth doing this manual compaction unless you are
storing the entire struct in some flash or its in a sensitive cache
thrashing structure.

bool is useful that it makes the code easier to read and can eliminate some
class of bugs that you would otherwise use !! operator.

> 
> No functional changed intended.
> 
> Signed-off-by: Li Nan <linan122@...wei.com>
> ---
>  block/badblocks.c         | 14 +++++++-------
>  include/linux/badblocks.h | 10 +++++-----
>  2 files changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/block/badblocks.c b/block/badblocks.c
> index 3afb550c0f7b..1b4caa42c5f1 100644
> --- a/block/badblocks.c
> +++ b/block/badblocks.c
> @@ -141,7 +141,7 @@ static void badblocks_update_acked(struct badblocks *bb)
>  	}
>  
>  	if (!unacked)
> -		bb->unacked_exist = 0;
> +		bb->unacked_exist = false;
>  }
>  
>  /**
> @@ -302,9 +302,9 @@ int badblocks_set(struct badblocks *bb, sector_t s, int sectors,
>  		}
>  	}
>  
> -	bb->changed = 1;
> +	bb->changed = true;
>  	if (!acknowledged)
> -		bb->unacked_exist = 1;
> +		bb->unacked_exist = true;
>  	else
>  		badblocks_update_acked(bb);
>  	write_sequnlock_irqrestore(&bb->lock, flags);
> @@ -414,7 +414,7 @@ int badblocks_clear(struct badblocks *bb, sector_t s, int sectors)
>  	}
>  
>  	badblocks_update_acked(bb);
> -	bb->changed = 1;
> +	bb->changed = true;
>  out:
>  	write_sequnlock_irq(&bb->lock);
>  	return rv;
> @@ -435,7 +435,7 @@ void ack_all_badblocks(struct badblocks *bb)
>  		return;
>  	write_seqlock_irq(&bb->lock);
>  
> -	if (bb->changed == 0 && bb->unacked_exist) {
> +	if (bb->changed == false && bb->unacked_exist) {

	if (!bb->changed && bb->unacked_exist)


>  		u64 *p = bb->page;
>  		int i;
>  
> @@ -447,7 +447,7 @@ void ack_all_badblocks(struct badblocks *bb)
>  				p[i] = BB_MAKE(start, len, 1);
>  			}
>  		}
> -		bb->unacked_exist = 0;
> +		bb->unacked_exist = false;
>  	}
>  	write_sequnlock_irq(&bb->lock);
>  }
> @@ -493,7 +493,7 @@ ssize_t badblocks_show(struct badblocks *bb, char *page, int unack)
>  				length << bb->shift);
>  	}
>  	if (unack && len == 0)
> -		bb->unacked_exist = 0;
> +		bb->unacked_exist = false;
>  
>  	if (read_seqretry(&bb->lock, seq))
>  		goto retry;
> diff --git a/include/linux/badblocks.h b/include/linux/badblocks.h
> index 2426276b9bd3..c2723f97d22d 100644
> --- a/include/linux/badblocks.h
> +++ b/include/linux/badblocks.h
> @@ -27,15 +27,15 @@
>  struct badblocks {
>  	struct device *dev;	/* set by devm_init_badblocks */
>  	int count;		/* count of bad blocks */
> -	int unacked_exist;	/* there probably are unacknowledged
> -				 * bad blocks.  This is only cleared
> -				 * when a read discovers none
> -				 */
>  	int shift;		/* shift from sectors to block size
>  				 * a -ve shift means badblocks are
>  				 * disabled.*/
> +	bool unacked_exist;	/* there probably are unacknowledged
> +				 * bad blocks.  This is only cleared
> +				 * when a read discovers none

read of what?

> +				 */
> +	bool changed;
>  	u64 *page;		/* badblock list */
> -	int changed;
>  	seqlock_t lock;
>  	sector_t sector;
>  	sector_t size;		/* in sectors */
> -- 
> 2.39.2
>