mm/vma: introduce [vma_flags,legacy]_to_[legacy,vma_flags]() helpers

While we are still converting VMA flags from vma_flags_t to vm_flags_t,
introduce helpers to convert between the two to allow for iterative
development without having to 'change the world' in a single commit'.

Also update VMA flags tests to reflect the change.

Finally, refresh vma_flags_overwrite_word(),
vma_flag_overwrite_word_once(), vma_flags_set_word() and
vma_flags_clear_word() in the VMA tests to reflect current kernel
implementations - this should make no functional difference, but keeps the
logic consistent between the two.

Link: https://lkml.kernel.org/r/d3569470dbb3ae79134ca7c3eb3fc4df7086e874.1774034900.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8ef84849953f..1da8fb04133f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -1070,6 +1070,18 @@ static __always_inline void vma_flags_clear_all(vma_flags_t *flags)
 }
 
 /*
+ * Helper function which converts a vma_flags_t value to a legacy vm_flags_t
+ * value. This is only valid if the input flags value can be expressed in a
+ * system word.
+ *
+ * Will be removed once the conversion to VMA flags is complete.
+ */
+static __always_inline vm_flags_t vma_flags_to_legacy(vma_flags_t flags)
+{
+	return (vm_flags_t)flags.__vma_flags[0];
+}
+
+/*
  * Copy value to the first system word of VMA flags, non-atomically.
  *
  * IMPORTANT: This does not overwrite bytes past the first system word. The
@@ -1083,6 +1095,20 @@ static inline void vma_flags_overwrite_word(vma_flags_t *flags, unsigned long va
 }
 
 /*
+ * Helper function which converts a legacy vm_flags_t value to a vma_flags_t
+ * value.
+ *
+ * Will be removed once the conversion to VMA flags is complete.
+ */
+static __always_inline vma_flags_t legacy_to_vma_flags(vm_flags_t flags)
+{
+	vma_flags_t ret = EMPTY_VMA_FLAGS;
+
+	vma_flags_overwrite_word(&ret, flags);
+	return ret;
+}
+
+/*
  * Copy value to the first system word of VMA flags ONCE, non-atomically.
  *
  * IMPORTANT: This does not overwrite bytes past the first system word. The