Re: [PATCH] dax: Add direct_access() callback check for dax_direct_access()

[Ira Weiny <ira.weiny@intel.com>]

Dave Jiang wrote:
> __devm_create_dev_dax() calls alloc_dax() with the ops parameter passed
> in as NULL. Therefore the ops pointer in dev_dax can be NULL. Add a
> check in dax_direct_access() for ops and ops->direct_access() before
> calling ops->direct_access().

Doesn't this need checking in dax_zero_page_range() and
dax_recovery_write() as well?

Ira

> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> ---
>  drivers/dax/super.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index c00b9dff4a06..5cebaf11a58e 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -160,6 +160,9 @@ long dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, long nr_pages,
>  	if (nr_pages < 0)
>  		return -EINVAL;
>  
> +	if (!dax_dev->ops || !dax_dev->ops->direct_access)
> +		return -EOPNOTSUPP;
> +
>  	avail = dax_dev->ops->direct_access(dax_dev, pgoff, nr_pages,
>  			mode, kaddr, pfn);
>  	if (!avail)
> 
> base-commit: 11439c4635edd669ae435eec308f4ab8a0804808
> -- 
> 2.53.0
> 
>