Merge tag 'virt-to-pfn-for-arch-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator into asm-generic

This is an attempt to harden the typing on virt_to_pfn()
and pfn_to_virt().

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, we do the same with pfn_to_virt().

The problem with this inconsistent typing was pointed out by
Russell King:
https://lore.kernel.org/linux-arm-kernel/YoJDKJXc0MJ2QZTb@shell.armlinux.org.uk/

And confirmed by Andrew Morton:
https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/

So the recognition of the problem is widespread.

These platforms have been chosen as initial conversion targets:

- ARM
- ARM64/Aarch64
- asm-generic (including for example x86)
- m68k

The idea is that if this goes in, it will block further misuse
of the function signatures due to the large compile coverage,
and then I can go in and fix the remaining architectures on a
one-by-one basis.

Some of the patches have been circulated before but were not
picked up by subsystem maintainers, so now the arch tree is
target for this series.

It has passed zeroday builds after a lot of iterations in my
personal tree, but there could be some randconfig outliers.
New added or deeply hidden problems appear all the time so
some minor fallout can be expected.

* tag 'virt-to-pfn-for-arch-v6.5-2' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-integrator:
  m68k/mm: Make pfn accessors static inlines
  arm64: memory: Make virt_to_pfn() a static inline
  ARM: mm: Make virt_to_pfn() a static inline
  asm-generic/page.h: Make pfn accessors static inlines
  xen/netback: Pass (void *) to virt_to_page()
  netfs: Pass a pointer to virt_to_page()
  cifs: Pass a pointer to virt_to_page() in cifsglob
  cifs: Pass a pointer to virt_to_page()
  riscv: mm: init: Pass a pointer to virt_to_page()
  ARC: init: Pass a pointer to virt_to_pfn() in init
  m68k: Pass a pointer to virt_to_pfn() virt_to_page()
  fs/proc/kcore.c: Pass a pointer to virt_addr_valid()

4 files changed, 4 insertions, 4 deletions

diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c
index 8a4c86687429..0431ec4a7298 100644
--- a/fs/netfs/iterator.c
+++ b/fs/netfs/iterator.c
@@ -240,7 +240,7 @@ static ssize_t netfs_extract_kvec_to_sg(struct iov_iter *iter,
 			if (is_vmalloc_or_module_addr((void *)kaddr))
 				page = vmalloc_to_page((void *)kaddr);
 			else
-				page = virt_to_page(kaddr);
+				page = virt_to_page((void *)kaddr);
 
 			sg_set_page(sg, page, len, off);
 			sgtable->nents++;
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 25b44b303b35..75708c66527f 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -199,7 +199,7 @@ kclist_add_private(unsigned long pfn, unsigned long nr_pages, void *arg)
 	ent->addr = (unsigned long)page_to_virt(p);
 	ent->size = nr_pages << PAGE_SHIFT;
 
-	if (!virt_addr_valid(ent->addr))
+	if (!virt_addr_valid((void *)ent->addr))
 		goto free_out;
 
 	/* cut not-mapped area. ....from ppc-32 code. */
diff --git a/fs/smb/client/cifsglob.h b/fs/smb/client/cifsglob.h
index 0d84bb1a8cd9..586a0cd2f713 100644
--- a/fs/smb/client/cifsglob.h
+++ b/fs/smb/client/cifsglob.h
@@ -2218,7 +2218,7 @@ static inline void cifs_sg_set_buf(struct sg_table *sgtable,
 		} while (buflen);
 	} else {
 		sg_set_page(&sgtable->sgl[sgtable->nents++],
-			    virt_to_page(addr), buflen, off);
+			    virt_to_page((void *)addr), buflen, off);
 	}
 }
 
diff --git a/fs/smb/client/smbdirect.c b/fs/smb/client/smbdirect.c
index 0362ebd4fa0f..964f07375a8d 100644
--- a/fs/smb/client/smbdirect.c
+++ b/fs/smb/client/smbdirect.c
@@ -2500,7 +2500,7 @@ static ssize_t smb_extract_kvec_to_rdma(struct iov_iter *iter,
 			if (is_vmalloc_or_module_addr((void *)kaddr))
 				page = vmalloc_to_page((void *)kaddr);
 			else
-				page = virt_to_page(kaddr);
+				page = virt_to_page((void *)kaddr);
 
 			if (!smb_set_sge(rdma, page, off, seg))
 				return -EIO;