Re: [PATCH v2 02/16] device/dax: update devdax to use mmap_prepare

[Jan Kara <jack@suse.cz>]

On Wed 10-09-25 21:21:57, Lorenzo Stoakes wrote:
> The devdax driver does nothing special in its f_op->mmap hook, so
> straightforwardly update it to use the mmap_prepare hook instead.
> 
> Acked-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  drivers/dax/device.c | 32 +++++++++++++++++++++-----------
>  1 file changed, 21 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/dax/device.c b/drivers/dax/device.c
> index 2bb40a6060af..c2181439f925 100644
> --- a/drivers/dax/device.c
> +++ b/drivers/dax/device.c
> @@ -13,8 +13,9 @@
>  #include "dax-private.h"
>  #include "bus.h"
>  
> -static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> -		const char *func)
> +static int __check_vma(struct dev_dax *dev_dax, vm_flags_t vm_flags,
> +		       unsigned long start, unsigned long end, struct file *file,
> +		       const char *func)
>  {
>  	struct device *dev = &dev_dax->dev;
>  	unsigned long mask;
> @@ -23,7 +24,7 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
>  		return -ENXIO;
>  
>  	/* prevent private mappings from being established */
> -	if ((vma->vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
> +	if ((vm_flags & VM_MAYSHARE) != VM_MAYSHARE) {
>  		dev_info_ratelimited(dev,
>  				"%s: %s: fail, attempted private mapping\n",
>  				current->comm, func);
> @@ -31,15 +32,15 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
>  	}
>  
>  	mask = dev_dax->align - 1;
> -	if (vma->vm_start & mask || vma->vm_end & mask) {
> +	if (start & mask || end & mask) {
>  		dev_info_ratelimited(dev,
>  				"%s: %s: fail, unaligned vma (%#lx - %#lx, %#lx)\n",
> -				current->comm, func, vma->vm_start, vma->vm_end,
> +				current->comm, func, start, end,
>  				mask);
>  		return -EINVAL;
>  	}
>  
> -	if (!vma_is_dax(vma)) {
> +	if (!file_is_dax(file)) {
>  		dev_info_ratelimited(dev,
>  				"%s: %s: fail, vma is not DAX capable\n",
>  				current->comm, func);
> @@ -49,6 +50,13 @@ static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
>  	return 0;
>  }
>  
> +static int check_vma(struct dev_dax *dev_dax, struct vm_area_struct *vma,
> +		     const char *func)
> +{
> +	return __check_vma(dev_dax, vma->vm_flags, vma->vm_start, vma->vm_end,
> +			   vma->vm_file, func);
> +}
> +
>  /* see "strong" declaration in tools/testing/nvdimm/dax-dev.c */
>  __weak phys_addr_t dax_pgoff_to_phys(struct dev_dax *dev_dax, pgoff_t pgoff,
>  		unsigned long size)
> @@ -285,8 +293,9 @@ static const struct vm_operations_struct dax_vm_ops = {
>  	.pagesize = dev_dax_pagesize,
>  };
>  
> -static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
> +static int dax_mmap_prepare(struct vm_area_desc *desc)
>  {
> +	struct file *filp = desc->file;
>  	struct dev_dax *dev_dax = filp->private_data;
>  	int rc, id;
>  
> @@ -297,13 +306,14 @@ static int dax_mmap(struct file *filp, struct vm_area_struct *vma)
>  	 * fault time.
>  	 */
>  	id = dax_read_lock();
> -	rc = check_vma(dev_dax, vma, __func__);
> +	rc = __check_vma(dev_dax, desc->vm_flags, desc->start, desc->end, filp,
> +			 __func__);
>  	dax_read_unlock(id);
>  	if (rc)
>  		return rc;
>  
> -	vma->vm_ops = &dax_vm_ops;
> -	vm_flags_set(vma, VM_HUGEPAGE);
> +	desc->vm_ops = &dax_vm_ops;
> +	desc->vm_flags |= VM_HUGEPAGE;
>  	return 0;
>  }
>  
> @@ -377,7 +387,7 @@ static const struct file_operations dax_fops = {
>  	.open = dax_open,
>  	.release = dax_release,
>  	.get_unmapped_area = dax_get_unmapped_area,
> -	.mmap = dax_mmap,
> +	.mmap_prepare = dax_mmap_prepare,
>  	.fop_flags = FOP_MMAP_SYNC,
>  };
>  
> -- 
> 2.51.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR