Re: [PATCH V7 01/24] dm: use bio_split() when splitting out the already processed bio

[Mike Snitzer]

On Wed, Jun 27 2018 at  8:45am -0400,
Ming Lei <ming.lei@xxxxxxxxxx> wrote:

> From: Mike Snitzer <snitzer@xxxxxxxxxx>
> 
> Use of bio_clone_bioset() is inefficient if there is no need to clone
> the original bio's bio_vec array.  Best to use the bio_clone_fast()
> variant.  Also, just using bio_advance() is only part of what is needed
> to properly setup the clone -- it doesn't account for the various
> bio_integrity() related work that also needs to be performed (see
> bio_split).
> 
> Address both of these issues by switching from bio_clone_bioset() to
> bio_split().
> 
> Fixes: 18a25da8 ("dm: ensure bio submission follows a depth-first tree walk")
> Cc: stable@xxxxxxxxxxxxxxx
> Reported-by: Christoph Hellwig <hch@xxxxxx>
> Reviewed-by: NeilBrown <neilb@xxxxxxxx>
> Reviewed-by: Ming Lei <ming.lei@xxxxxxxxxx>
> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>

FYI, I'll be sending this to Linus tomorrow.

Mike