Re: [PATCH v5 RESEND 06/17] mm/ioremap: add slab availability checking in ioremap_prot

[Baoquan He <bhe@xxxxxxxxxx>]

On 05/16/23 at 11:30pm, Christoph Hellwig wrote:
> On Mon, May 15, 2023 at 05:08:37PM +0800, Baoquan He wrote:
> > Several architectures has done checking if slab if available in
> > ioremap_prot(). In fact it should be done in generic ioremap_prot()
> > since on any architecutre, slab allocator must be available before
> > get_vm_area_caller() and vunmap() are used.
> > 
> > Add the checking into generic_ioremap_prot().
> 
> Should we add a WARN_ON/WARN_ON_ONCE to aid debugging?

Sounds like a great idea, will add WARN_ON_ONCE as below. Thanks.

	if (WARN_ON_ONCE(!slab_is_available()))
		return NULL;