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[PATCH v3 6/8] cxl/region: Move ready-to-probe state check to a helper

Dan Williams posted 8 patches 2 months, 3 weeks ago
[PATCH v3 6/8] cxl/region: Move ready-to-probe state check to a helper
Posted by Dan Williams 2 months, 3 weeks ago 
Rather than unlocking the region rwsem in the middle of cxl_region_probe()
create a helper for determining when the region is ready-to-probe.

Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 drivers/cxl/core/region.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
index 3a77aec2c447..2a97fa9a394f 100644
--- a/drivers/cxl/core/region.c
+++ b/drivers/cxl/core/region.c
@@ -3572,9 +3572,8 @@ static void shutdown_notifiers(void *_cxlr)
 	unregister_mt_adistance_algorithm(&cxlr->adist_notifier);
 }
 
-static int cxl_region_probe(struct device *dev)
+static int cxl_region_can_probe(struct cxl_region *cxlr)
 {
-	struct cxl_region *cxlr = to_cxl_region(dev);
 	struct cxl_region_params *p = &cxlr->params;
 	int rc;
 
@@ -3597,15 +3596,28 @@ static int cxl_region_probe(struct device *dev)
 		goto out;
 	}
 
-	/*
-	 * From this point on any path that changes the region's state away from
-	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
-	 */
 out:
 	up_read(&cxl_region_rwsem);
 
 	if (rc)
 		return rc;
+	return 0;
+}
+
+static int cxl_region_probe(struct device *dev)
+{
+	struct cxl_region *cxlr = to_cxl_region(dev);
+	struct cxl_region_params *p = &cxlr->params;
+	int rc;
+
+	rc = cxl_region_can_probe(cxlr);
+	if (rc)
+		return rc;
+
+	/*
+	 * From this point on any path that changes the region's state away from
+	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
+	 */
 
 	cxlr->memory_notifier.notifier_call = cxl_region_perf_attrs_callback;
 	cxlr->memory_notifier.priority = CXL_CALLBACK_PRI;
-- 
2.50.0
Re: [PATCH v3 6/8] cxl/region: Move ready-to-probe state check to a helper
Posted by Jonathan Cameron 2 months, 3 weeks ago 
On Fri, 11 Jul 2025 16:49:30 -0700
Dan Williams <dan.j.williams@intel.com> wrote:

> Rather than unlocking the region rwsem in the middle of cxl_region_probe()
> create a helper for determining when the region is ready-to-probe.
I'd maybe mention the odd bit of 
if (rc)
	return rc;

return 0;

Will go away shortly. Or maybe that is overkill for a commit message.

Anyhow, with that in mind LGTM
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>


> 
> Cc: Davidlohr Bueso <dave@stgolabs.net>
> Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> ---
>  drivers/cxl/core/region.c | 24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 3a77aec2c447..2a97fa9a394f 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3572,9 +3572,8 @@ static void shutdown_notifiers(void *_cxlr)
>  	unregister_mt_adistance_algorithm(&cxlr->adist_notifier);
>  }
>  
> -static int cxl_region_probe(struct device *dev)
> +static int cxl_region_can_probe(struct cxl_region *cxlr)
>  {
> -	struct cxl_region *cxlr = to_cxl_region(dev);
>  	struct cxl_region_params *p = &cxlr->params;
>  	int rc;
>  
> @@ -3597,15 +3596,28 @@ static int cxl_region_probe(struct device *dev)
>  		goto out;
>  	}
>  
> -	/*
> -	 * From this point on any path that changes the region's state away from
> -	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
> -	 */
>  out:
>  	up_read(&cxl_region_rwsem);
>  
>  	if (rc)
>  		return rc;
> +	return 0;

This is an odd bit of code now.  Why not just

	return rc;

Ah. Patch 8 drops the if (rc) return rc bit.



> +}
> +
> +static int cxl_region_probe(struct device *dev)
> +{
> +	struct cxl_region *cxlr = to_cxl_region(dev);
> +	struct cxl_region_params *p = &cxlr->params;
> +	int rc;
> +
> +	rc = cxl_region_can_probe(cxlr);
> +	if (rc)
> +		return rc;
> +
> +	/*
> +	 * From this point on any path that changes the region's state away from
> +	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
> +	 */
>  
>  	cxlr->memory_notifier.notifier_call = cxl_region_perf_attrs_callback;
>  	cxlr->memory_notifier.priority = CXL_CALLBACK_PRI;
Re: [PATCH v3 6/8] cxl/region: Move ready-to-probe state check to a helper
Posted by dan.j.williams@intel.com 2 months, 3 weeks ago 
Jonathan Cameron wrote:
> On Fri, 11 Jul 2025 16:49:30 -0700
> Dan Williams <dan.j.williams@intel.com> wrote:
> 
> > Rather than unlocking the region rwsem in the middle of cxl_region_probe()
> > create a helper for determining when the region is ready-to-probe.
> I'd maybe mention the odd bit of 
> if (rc)
> 	return rc;
> 
> return 0;
> 
> Will go away shortly. Or maybe that is overkill for a commit message.
> 
> Anyhow, with that in mind LGTM
> Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
> 
> 
> > 
> > Cc: Davidlohr Bueso <dave@stgolabs.net>
> > Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
> > Cc: Dave Jiang <dave.jiang@intel.com>
> > Cc: Alison Schofield <alison.schofield@intel.com>
> > Cc: Vishal Verma <vishal.l.verma@intel.com>
> > Cc: Ira Weiny <ira.weiny@intel.com>
> > Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> > Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> > Signed-off-by: Dan Williams <dan.j.williams@intel.com>
> > ---
> >  drivers/cxl/core/region.c | 24 ++++++++++++++++++------
> >  1 file changed, 18 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> > index 3a77aec2c447..2a97fa9a394f 100644
> > --- a/drivers/cxl/core/region.c
> > +++ b/drivers/cxl/core/region.c
> > @@ -3572,9 +3572,8 @@ static void shutdown_notifiers(void *_cxlr)
> >  	unregister_mt_adistance_algorithm(&cxlr->adist_notifier);
> >  }
> >  
> > -static int cxl_region_probe(struct device *dev)
> > +static int cxl_region_can_probe(struct cxl_region *cxlr)
> >  {
> > -	struct cxl_region *cxlr = to_cxl_region(dev);
> >  	struct cxl_region_params *p = &cxlr->params;
> >  	int rc;
> >  
> > @@ -3597,15 +3596,28 @@ static int cxl_region_probe(struct device *dev)
> >  		goto out;
> >  	}
> >  
> > -	/*
> > -	 * From this point on any path that changes the region's state away from
> > -	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
> > -	 */
> >  out:
> >  	up_read(&cxl_region_rwsem);
> >  
> >  	if (rc)
> >  		return rc;
> > +	return 0;
> 
> This is an odd bit of code now.  Why not just
> 
> 	return rc;
> 
> Ah. Patch 8 drops the if (rc) return rc bit.

It was an artifact of how it was developed. I am inclined to let it be
unless something else major comes up.
Re: [PATCH v3 6/8] cxl/region: Move ready-to-probe state check to a helper
Posted by Fabio M. De Francesco 2 months, 3 weeks ago 
On Saturday, July 12, 2025 1:49:30 AM Central European Summer Time Dan Williams wrote:
> Rather than unlocking the region rwsem in the middle of cxl_region_probe()
> create a helper for determining when the region is ready-to-probe.
> 
> Cc: Davidlohr Bueso <dave@stgolabs.net>
> Cc: Jonathan Cameron <jonathan.cameron@huawei.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Alison Schofield <alison.schofield@intel.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Ira Weiny <ira.weiny@intel.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Fabio M. De Francesco <fabio.m.de.francesco@linux.intel.com>

> ---
>  drivers/cxl/core/region.c | 24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/cxl/core/region.c b/drivers/cxl/core/region.c
> index 3a77aec2c447..2a97fa9a394f 100644
> --- a/drivers/cxl/core/region.c
> +++ b/drivers/cxl/core/region.c
> @@ -3572,9 +3572,8 @@ static void shutdown_notifiers(void *_cxlr)
>  	unregister_mt_adistance_algorithm(&cxlr->adist_notifier);
>  }
>  
> -static int cxl_region_probe(struct device *dev)
> +static int cxl_region_can_probe(struct cxl_region *cxlr)
>  {
> -	struct cxl_region *cxlr = to_cxl_region(dev);
>  	struct cxl_region_params *p = &cxlr->params;
>  	int rc;
>  
> @@ -3597,15 +3596,28 @@ static int cxl_region_probe(struct device *dev)
>  		goto out;
>  	}
>  
> -	/*
> -	 * From this point on any path that changes the region's state away from
> -	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
> -	 */
>  out:
>  	up_read(&cxl_region_rwsem);
>  
>  	if (rc)
>  		return rc;
> +	return 0;
> +}
> +
> +static int cxl_region_probe(struct device *dev)
> +{
> +	struct cxl_region *cxlr = to_cxl_region(dev);
> +	struct cxl_region_params *p = &cxlr->params;
> +	int rc;
> +
> +	rc = cxl_region_can_probe(cxlr);
> +	if (rc)
> +		return rc;
> +
> +	/*
> +	 * From this point on any path that changes the region's state away from
> +	 * CXL_CONFIG_COMMIT is also responsible for releasing the driver.
> +	 */
>  
>  	cxlr->memory_notifier.notifier_call = cxl_region_perf_attrs_callback;
>  	cxlr->memory_notifier.priority = CXL_CALLBACK_PRI;
> -- 
> 2.50.0
> 
> 
>

Patchew 2.1-devel-b67e4c2

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