Re: [PATCH v16 06/11] mm: introduce memfd_secret system call to create "secret" memory areas

[Mike Rapoport]

On Wed, Feb 03, 2021 at 01:15:58PM +0100, Michal Hocko wrote:
> On Thu 21-01-21 14:27:18, Mike Rapoport wrote:
> > +static struct file *secretmem_file_create(unsigned long flags)
> > +{
> > +	struct file *file = ERR_PTR(-ENOMEM);
> > +	struct secretmem_ctx *ctx;
> > +	struct inode *inode;
> > +
> > +	inode = alloc_anon_inode(secretmem_mnt->mnt_sb);
> > +	if (IS_ERR(inode))
> > +		return ERR_CAST(inode);
> > +
> > +	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
> > +	if (!ctx)
> > +		goto err_free_inode;
> > +
> > +	file = alloc_file_pseudo(inode, secretmem_mnt, "secretmem",
> > +				 O_RDWR, &secretmem_fops);
> > +	if (IS_ERR(file))
> > +		goto err_free_ctx;
> > +
> > +	mapping_set_unevictable(inode->i_mapping);
> 
> Btw. you need also mapping_set_gfp_mask(mapping, GFP_HIGHUSER) because
> the default is GFP_HIGHUSER_MOVABLE and you do not support migration so
> no pages from movable zones should be allowed.

Ok.

-- 
Sincerely yours,
Mike.