Re: [PATCH v2 5/8] cxl/region: Split commit_store() into __commit() and queue_reset() helpers

[dan.j.williams]

Alison Schofield wrote:
> On Wed, Jun 18, 2025 at 10:04:13PM -0700, Dan Williams wrote:
> > The complexity of dropping the lock is removed in favor of splitting commit
> > operations to a helper, and leaving all the complexities of "decommit" for
> > commit_store() to coordinate the different locking contexts.
> > 
> > The CPU cache-invalidation in the decommit path is solely handled now by
> > cxl_region_decode_reset(). Previously the CPU caches were being needlessly
> > flushed twice in the decommit path where the first flush had no guarantee
> > that the memory would not be immediately re-dirtied.
> > 
> > Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> > Cc: Jonathan Cameron <jonathan.cameron@xxxxxxxxxx>
> > Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
> > Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
> > Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
> > Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> > ---
> >  drivers/cxl/core/region.c | 99 +++++++++++++++++++++++++++------------
> >  1 file changed, 70 insertions(+), 29 deletions(-)
> > 
> > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> > index 6e5e1460068d..3a77aec2c447 100644
> > --- a/drivers/cxl/core/region.c
> > +++ b/drivers/cxl/core/region.c
> > @@ -349,30 +349,42 @@ static int cxl_region_decode_commit(struct cxl_region *cxlr)
> >  	return rc;
> >  }
> >  
> > -static ssize_t commit_store(struct device *dev, struct device_attribute *attr,
> > -			    const char *buf, size_t len)
> > +static int queue_reset(struct cxl_region *cxlr)
> 
> How about defining both new helpers to return ssize_t type for consistency
> with sysfs functions. The local 'int rc' can remain as long as the function
> return type is ssize_t.

The type change to 'int' for the helpers that are not dealing with
input/ouput is deliberate. queue_reset() is never returning a "size", it
is always returning 0 or a negative error code. An int fits in ssize_t.