Re: [PATCH ndctl RESEND 2/2] cxl/region: Fix memory device teardown in disable-region

[Dave Jiang <dave.jiang@intel.com>]

On 11/30/23 21:06, Ira Weiny wrote:
> When a region is requested to be disabled, memory devices are normally
> automatically torn down.  Commit 9399aa667ab0 prevents tear down if
> memory is online without a force flag.  However, daxctl_dev_get_memory()
> may return NULL if the memory device in question is not system-ram
> capable as is the case for a region with only devdax devices.  Such
> devices do not need to be off-lined explicitly.
> 
> Skip non-system-ram devices rather than error the operation.
> 
> Fixes: 9399aa667ab0 ("cxl/region: Add -f option for disable-region")
> Cc: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> ---
>  cxl/region.c             | 3 +++
>  daxctl/lib/libdaxctl.c   | 4 ++--
>  daxctl/lib/libdaxctl.sym | 5 +++++
>  daxctl/libdaxctl.h       | 1 +
>  4 files changed, 11 insertions(+), 2 deletions(-)
> 
> diff --git a/cxl/region.c b/cxl/region.c
> index 5cbbf2749e2d..44ac76b001e9 100644
> --- a/cxl/region.c
> +++ b/cxl/region.c
> @@ -805,6 +805,9 @@ static int disable_region(struct cxl_region *region)
>  		goto out;
>  
>  	daxctl_dev_foreach(dax_region, dev) {
> +		if (!daxctl_dev_is_system_ram_capable(dev))
> +			continue;
> +
>  		mem = daxctl_dev_get_memory(dev);
>  		if (!mem)
>  			return -ENXIO;
> diff --git a/daxctl/lib/libdaxctl.c b/daxctl/lib/libdaxctl.c
> index 4f9aba0b09f2..9fbefe2e8329 100644
> --- a/daxctl/lib/libdaxctl.c
> +++ b/daxctl/lib/libdaxctl.c
> @@ -385,7 +385,7 @@ static bool device_model_is_dax_bus(struct daxctl_dev *dev)
>  	return false;
>  }
>  
> -static int dev_is_system_ram_capable(struct daxctl_dev *dev)
> +DAXCTL_EXPORT int daxctl_dev_is_system_ram_capable(struct daxctl_dev *dev)
>  {
>  	const char *devname = daxctl_dev_get_devname(dev);
>  	struct daxctl_ctx *ctx = daxctl_dev_get_ctx(dev);
> @@ -432,7 +432,7 @@ static struct daxctl_memory *daxctl_dev_alloc_mem(struct daxctl_dev *dev)
>  	char buf[SYSFS_ATTR_SIZE];
>  	int node_num;
>  
> -	if (!dev_is_system_ram_capable(dev))
> +	if (!daxctl_dev_is_system_ram_capable(dev))
>  		return NULL;
>  
>  	mem = calloc(1, sizeof(*mem));
> diff --git a/daxctl/lib/libdaxctl.sym b/daxctl/lib/libdaxctl.sym
> index fe68fd0a9cde..309881196c86 100644
> --- a/daxctl/lib/libdaxctl.sym
> +++ b/daxctl/lib/libdaxctl.sym
> @@ -99,3 +99,8 @@ global:
>  	daxctl_set_config_path;
>  	daxctl_get_config_path;
>  } LIBDAXCTL_8;
> +
> +LIBDAXCTL_10 {
> +global:
> +	daxctl_dev_is_system_ram_capable;
> +} LIBDAXCTL_9;
> diff --git a/daxctl/libdaxctl.h b/daxctl/libdaxctl.h
> index 6876037a9427..53c6bbdae5c3 100644
> --- a/daxctl/libdaxctl.h
> +++ b/daxctl/libdaxctl.h
> @@ -77,6 +77,7 @@ int daxctl_dev_will_auto_online_memory(struct daxctl_dev *dev);
>  int daxctl_dev_has_online_memory(struct daxctl_dev *dev);
>  
>  struct daxctl_memory;
> +int daxctl_dev_is_system_ram_capable(struct daxctl_dev *dev);
>  struct daxctl_memory *daxctl_dev_get_memory(struct daxctl_dev *dev);
>  struct daxctl_dev *daxctl_memory_get_dev(struct daxctl_memory *mem);
>  const char *daxctl_memory_get_node_path(struct daxctl_memory *mem);
>