Re: [dm-devel] [PATCH 08/15] dm mpath: merge do_end_io_bio into multipath_end_io_bio

[Martin Wilck <mwilck@suse.com>]

On Thu, 2017-05-18 at 15:18 +0200, Christoph Hellwig wrote:
> This simplifies the code and especially the error passing a bit and
> will help with the next patch.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/md/dm-mpath.c | 42 ++++++++++++++++-------------------------
> -
>  1 file changed, 16 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
> index 3df056b73b66..b1cb0273b081 100644
> --- a/drivers/md/dm-mpath.c
> +++ b/drivers/md/dm-mpath.c
> @@ -1510,24 +1510,26 @@ static int multipath_end_io(struct dm_target
> *ti, struct request *clone,
>  	return r;
>  }
>  
> -static int do_end_io_bio(struct multipath *m, struct bio *clone,
> -			 int error, struct dm_mpath_io *mpio)
> +static int multipath_end_io_bio(struct dm_target *ti, struct bio
> *clone, int error)
>  {
> +	struct multipath *m = ti->private;
> +	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
> +	struct pgpath *pgpath = mpio->pgpath;
>  	unsigned long flags;
>  
> -	if (!error)
> -		return 0;	/* I/O complete */
> +	BUG_ON(!mpio);

You dereferenced mpio already above.

Regards,
Martin

>  
> -	if (noretry_error(error))
> -		return error;
> +	if (!error || noretry_error(error))
> +		goto done;
>  
> -	if (mpio->pgpath)
> -		fail_path(mpio->pgpath);
> +	if (pgpath)
> +		fail_path(pgpath);
>  
>  	if (atomic_read(&m->nr_valid_paths) == 0 &&
>  	    !test_bit(MPATHF_QUEUE_IF_NO_PATH, &m->flags)) {
>  		dm_report_EIO(m);
> -		return -EIO;
> +		error = -EIO;
> +		goto done;
>  	}
>  
>  	/* Queue for the daemon to resubmit */
> @@ -1539,28 +1541,16 @@ static int do_end_io_bio(struct multipath *m,
> struct bio *clone,
>  	if (!test_bit(MPATHF_QUEUE_IO, &m->flags))
>  		queue_work(kmultipathd, &m->process_queued_bios);
>  
> -	return DM_ENDIO_INCOMPLETE;
> -}
> -
> -static int multipath_end_io_bio(struct dm_target *ti, struct bio
> *clone, int error)
> -{
> -	struct multipath *m = ti->private;
> -	struct dm_mpath_io *mpio = get_mpio_from_bio(clone);
> -	struct pgpath *pgpath;
> -	struct path_selector *ps;
> -	int r;
> -
> -	BUG_ON(!mpio);
> -
> -	r = do_end_io_bio(m, clone, error, mpio);
> -	pgpath = mpio->pgpath;
> +	error = DM_ENDIO_INCOMPLETE;
> +done:
>  	if (pgpath) {
> -		ps = &pgpath->pg->ps;
> +		struct path_selector *ps = &pgpath->pg->ps;
> +
>  		if (ps->type->end_io)
>  			ps->type->end_io(ps, &pgpath->path, mpio-
> >nr_bytes);
>  	}
>  
> -	return r;
> +	return error;
>  }
>  
>  /*

-- 
Dr. Martin Wilck <mwilck@suse.com>, Tel. +49 (0)911 74053 2107
SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton
HRB 21284 (AG Nürnberg)