mm: change vm_get_page_prot() to accept vm_flags_t argument

Patch series "use vm_flags_t consistently".

The VMA flags field vma->vm_flags is of type vm_flags_t.  Right now this
is exactly equivalent to unsigned long, but it should not be assumed to
be.

Much code that references vma->vm_flags already correctly uses vm_flags_t,
but a fairly large chunk of code simply uses unsigned long and assumes
that the two are equivalent.

This series corrects that and has us use vm_flags_t consistently.

This series is motivated by the desire to, in a future series, adjust
vm_flags_t to be a u64 regardless of whether the kernel is 32-bit or
64-bit in order to deal with the VMA flag exhaustion issue and avoid all
the various problems that arise from it (being unable to use certain
features in 32-bit, being unable to add new flags except for 64-bit, etc.)

This is therefore a critical first step towards that goal.  At any rate,
using the correct type is of value regardless.

We additionally take the opportunity to refer to VMA flags as vm_flags
where possible to make clear what we're referring to.

Overall, this series does not introduce any functional change.


This patch (of 3):

We abstract the type of the VMA flags to vm_flags_t, however in may places
it is simply assumed this is unsigned long, which is simply incorrect.

At the moment this is simply an incongruity, however in future we plan to
change this type and therefore this change is a critical requirement for
doing so.

Overall, this patch does not introduce any functional change.

[lorenzo.stoakes@oracle.com: add missing vm_get_page_prot() instance, remove include]
  Link: https://lkml.kernel.org/r/552f88e1-2df8-4e95-92b8-812f7c8db829@lucifer.local
Link: https://lkml.kernel.org/r/cover.1750274467.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/a12769720a2743f235643b158c4f4f0a9911daf0.1750274467.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Acked-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

5 files changed, 5 insertions, 5 deletions

diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index c86c348857c4..08ee177432c2 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -81,7 +81,7 @@ static int __init adjust_protection_map(void)
 }
 arch_initcall(adjust_protection_map);
 
-pgprot_t vm_get_page_prot(unsigned long vm_flags)
+pgprot_t vm_get_page_prot(vm_flags_t vm_flags)
 {
 	ptdesc_t prot;
 
diff --git a/arch/powerpc/include/asm/book3s/64/pkeys.h b/arch/powerpc/include/asm/book3s/64/pkeys.h
index 5b178139f3c0..ff911b4251d9 100644
--- a/arch/powerpc/include/asm/book3s/64/pkeys.h
+++ b/arch/powerpc/include/asm/book3s/64/pkeys.h
@@ -5,7 +5,7 @@
 
 #include <asm/book3s/64/hash-pkey.h>
 
-static inline u64 vmflag_to_pte_pkey_bits(u64 vm_flags)
+static inline u64 vmflag_to_pte_pkey_bits(vm_flags_t vm_flags)
 {
 	if (!mmu_has_feature(MMU_FTR_PKEY))
 		return 0x0UL;
diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c
index 0db01e10a3f8..a89ef89101fc 100644
--- a/arch/powerpc/mm/book3s64/pgtable.c
+++ b/arch/powerpc/mm/book3s64/pgtable.c
@@ -644,7 +644,7 @@ unsigned long memremap_compat_align(void)
 EXPORT_SYMBOL_GPL(memremap_compat_align);
 #endif
 
-pgprot_t vm_get_page_prot(unsigned long vm_flags)
+pgprot_t vm_get_page_prot(vm_flags_t vm_flags)
 {
 	unsigned long prot;
 
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 25ae4c897aae..7ed58bf3aaca 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -3201,7 +3201,7 @@ void copy_highpage(struct page *to, struct page *from)
 }
 EXPORT_SYMBOL(copy_highpage);
 
-pgprot_t vm_get_page_prot(unsigned long vm_flags)
+pgprot_t vm_get_page_prot(vm_flags_t vm_flags)
 {
 	unsigned long prot = pgprot_val(protection_map[vm_flags &
 					(VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);
diff --git a/arch/x86/mm/pgprot.c b/arch/x86/mm/pgprot.c
index c84bd9540b16..dc1afd5c839d 100644
--- a/arch/x86/mm/pgprot.c
+++ b/arch/x86/mm/pgprot.c
@@ -32,7 +32,7 @@ void add_encrypt_protection_map(void)
 		protection_map[i] = pgprot_encrypted(protection_map[i]);
 }
 
-pgprot_t vm_get_page_prot(unsigned long vm_flags)
+pgprot_t vm_get_page_prot(vm_flags_t vm_flags)
 {
 	unsigned long val = pgprot_val(protection_map[vm_flags &
 				      (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]);