Re: [PATCH RFC v2 02/14] md/md-bitmap: pass discard information to bitmap_{start, end}write

[Christoph Hellwig]

>  	int (*startwrite)(struct mddev *mddev, sector_t offset,
> -			  unsigned long sectors);
> +			  unsigned long sectors, bool is_discard);
>  	void (*endwrite)(struct mddev *mddev, sector_t offset,
> -			 unsigned long sectors);
> +			 unsigned long sectors, bool is_discard);

a bool discard is not a very good interface.  I'd expect an op enum or a set
of flag to properly describe it.

But is start/end write really the right interface for discard or should it
have it's own set of ops?