Re: [PATCH v3 3/4] cxl/core: Add locked variants of the poison inject and clear funcs

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Sat, 12 Jul 2025 19:37:56 -0700
alison.schofield@intel.com wrote:

> From: Alison Schofield <alison.schofield@intel.com>
> 
> The core functions that validate and send inject and clear commands
> to the memdev devices require holding both the dpa_rwsem and the
> region_rwsem.
> 
> In preparation for another caller of these functions that must hold
> the locks upon entry, split the work into a locked and unlocked pair.
> 
> Consideration was given to moving the locking to both callers,
> however, the existing caller is not in the core (mem.c) and cannot
> access the locks.
> 
> Signed-off-by: Alison Schofield <alison.schofield@intel.com>

Trivial comment to cleanup inline.

Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>

> @@ -324,9 +319,26 @@ int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
>  
>  	return 0;
>  }
> +
> +int cxl_inject_poison(struct cxl_memdev *cxlmd, u64 dpa)
> +{
> +	int rc;
> +
> +	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
> +	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
> +		return rc;
> +
> +	ACQUIRE(rwsem_read_intr, dpa_rwsem)(&cxl_rwsem.dpa);
> +	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &dpa_rwsem)))
> +		return rc;
> +
> +	rc = cxl_inject_poison_locked(cxlmd, dpa);
> +
> +	return rc;

	return cxl_inject_poison_locked(cxlmd, dpa);

> +}
>  EXPORT_SYMBOL_NS_GPL(cxl_inject_poison, "CXL");

> +
> +int cxl_clear_poison(struct cxl_memdev *cxlmd, u64 dpa)
> +{
> +	int rc;
> +
> +	ACQUIRE(rwsem_read_intr, region_rwsem)(&cxl_rwsem.region);
> +	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &region_rwsem)))
> +		return rc;
> +
> +	ACQUIRE(rwsem_read_intr, dpa_rwsem)(&cxl_rwsem.dpa);
> +	if ((rc = ACQUIRE_ERR(rwsem_read_intr, &dpa_rwsem)))
> +		return rc;
> +
> +	rc = cxl_clear_poison_locked(cxlmd, dpa);
> +
> +	return rc;
> +}

	return cxl_clear_poison_locked(cxlmd, dpa);

I wondered if this was to save churn in a later patch, but
not seeing anything related in patch 4.

>  EXPORT_SYMBOL_NS_GPL(cxl_clear_poison, "CXL");