mm/vma: add append_vma_flags() helper

In order to be able to efficiently combine VMA flag masks with additional
VMA flag bits we need to extend the concept introduced in mk_vma_flags()
and __mk_vma_flags() by allowing the specification of a VMA flag mask to
append VMA flag bits to.

Update __mk_vma_flags() to allow for this and update mk_vma_flags()
accordingly, and also provide append_vma_flags() to allow for the caller
to specify which VMA flags mask to append to.

Finally, update the VMA flags tests to reflect the change.

Link: https://lkml.kernel.org/r/9f928cd4688270002f2c0c3777fcc9b49cc7a8ea.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, 14 insertions, 6 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index d7e647e31742..26cfb2fbe4db 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1042,13 +1042,11 @@ static __always_inline void vma_flags_set_flag(vma_flags_t *flags,
 	__set_bit((__force int)bit, bitmap);
 }
 
-static __always_inline vma_flags_t __mk_vma_flags(size_t count,
-		const vma_flag_t *bits)
+static __always_inline vma_flags_t __mk_vma_flags(vma_flags_t flags,
+		size_t count, const vma_flag_t *bits)
 {
-	vma_flags_t flags;
 	int i;
 
-	vma_flags_clear_all(&flags);
 	for (i = 0; i < count; i++)
 		vma_flags_set_flag(&flags, bits[i]);
 	return flags;
@@ -1064,8 +1062,18 @@ static __always_inline vma_flags_t __mk_vma_flags(size_t count,
  * The compiler cleverly optimises away all of the work and this ends up being
  * equivalent to aggregating the values manually.
  */
-#define mk_vma_flags(...) __mk_vma_flags(COUNT_ARGS(__VA_ARGS__), \
-					 (const vma_flag_t []){__VA_ARGS__})
+#define mk_vma_flags(...) __mk_vma_flags(EMPTY_VMA_FLAGS,			\
+		COUNT_ARGS(__VA_ARGS__), (const vma_flag_t []){__VA_ARGS__})
+
+/*
+ * Helper macro which acts like mk_vma_flags, only appending to a copy of the
+ * specified flags rather than establishing new flags. E.g.:
+ *
+ * vma_flags_t flags = append_vma_flags(VMA_STACK_DEFAULT_FLAGS, VMA_STACK_BIT,
+ *              VMA_ACCOUNT_BIT);
+ */
+#define append_vma_flags(flags, ...) __mk_vma_flags(flags,			\
+		COUNT_ARGS(__VA_ARGS__), (const vma_flag_t []){__VA_ARGS__})
 
 /*
  * Test whether a specific VMA flag is set, e.g.: