s390/mm: make virt_to_pfn() a static inline

Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

For symmetry do the same with pfn_to_virt() reflecting the
current layout in asm-generic/page.h.

Doing this reveals a number of offenders in the arch code and
the S390-specific drivers, so just bite the bullet and fix up
all of those as well.

Signed-off-by: Linus Walleij <[e-mail]>
Reviewed-by: Alexander Gordeev <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Heiko Carstens <[e-mail]>

arch/s390/include/asm/kfence.h

···
 
 static inline bool kfence_protect_page(unsigned long addr, bool protect)
 {
-	__kernel_map_pages(virt_to_page(addr), 1, !protect);
+	__kernel_map_pages(virt_to_page((void *)addr), 1, !protect);
 	return true;
 }
 

arch/s390/include/asm/page.h

···
 #define phys_to_page(phys)	pfn_to_page(phys_to_pfn(phys))
 #define page_to_phys(page)	pfn_to_phys(page_to_pfn(page))
 
-#define pfn_to_virt(pfn)	__va(pfn_to_phys(pfn))
-#define virt_to_pfn(kaddr)	(phys_to_pfn(__pa(kaddr)))
+static inline void *pfn_to_virt(unsigned long pfn)
+{
+	return __va(pfn_to_phys(pfn));
+}
+
+static inline unsigned long virt_to_pfn(const void *kaddr)
+{
+	return phys_to_pfn(__pa(kaddr));
+}
+
 #define pfn_to_kaddr(pfn)	pfn_to_virt(pfn)
 
 #define virt_to_page(kaddr)	pfn_to_page(virt_to_pfn(kaddr))

arch/s390/mm/cmm.c

···
 			} else
 				free_page((unsigned long) npa);
 		}
-		diag10_range(virt_to_pfn(addr), 1);
+		diag10_range(virt_to_pfn((void *)addr), 1);
 		pa->pages[pa->index++] = addr;
 		(*counter)++;
 		spin_unlock(&cmm_lock);

arch/s390/mm/vmem.c

···
 {
 	/* We don't expect boot memory to be removed ever. */
 	if (!slab_is_available() ||
-	    WARN_ON_ONCE(PageReserved(virt_to_page(addr))))
+	    WARN_ON_ONCE(PageReserved(virt_to_page((void *)addr))))
 		return;
 	free_pages(addr, order);
 }

drivers/s390/block/scm_blk.c

···
 
 		if ((msb->flags & MSB_FLAG_IDA) && aidaw &&
 		    IS_ALIGNED(aidaw, PAGE_SIZE))
-			mempool_free(virt_to_page(aidaw), aidaw_pool);
+			mempool_free(virt_to_page((void *)aidaw), aidaw_pool);
 	}
 
 	spin_lock_irqsave(&list_lock, flags);

drivers/s390/char/vmcp.c

···
 	order = get_order(session->bufsize);
 	nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT;
 	if (session->cma_alloc) {
-		page = virt_to_page((unsigned long)session->response);
+		page = virt_to_page(session->response);
 		cma_release(vmcp_cma, page, nr_pages);
 		session->cma_alloc = 0;
 	} else {