The patch titled
Subject: mm: introduce vma->vm_flags wrapper functions
has been added to the -mm mm-unstable branch. Its filename is
mm-introduce-vma-vm_flags-wrapper-functions.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-introduce-vma-vm_flags-wrapper-functions.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Subject: mm: introduce vma->vm_flags wrapper functions
Date: Thu, 26 Jan 2023 11:37:47 -0800
vm_flags are among VMA attributes which affect decisions like VMA merging
and splitting. Therefore all vm_flags modifications are performed after
taking exclusive mmap_lock to prevent vm_flags updates racing with such
operations. Introduce modifier functions for vm_flags to be used whenever
flags are updated. This way we can better check and control correct
locking behavior during these updates.
Link: https://lkml.kernel.org/r/20230126193752.297968-3-surenb@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Acked-by: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arjun Roy <arjunroy@xxxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Eric Dumazet <edumazet@xxxxxxxxxx>
Cc: Greg Thelen <gthelen@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Joel Fernandes <joelaf@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Laurent Dufour <ldufour@xxxxxxxxxxxxx>
Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Peter Oskolkov <posk@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Punit Agrawal <punit.agrawal@xxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Soheil Hassas Yeganeh <soheil@xxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 40 +++++++++++++++++++++++++++++++++++++
include/linux/mm_types.h | 10 ++++++++-
2 files changed, 49 insertions(+), 1 deletion(-)
--- a/include/linux/mm.h~mm-introduce-vma-vm_flags-wrapper-functions
+++ a/include/linux/mm.h
@@ -627,6 +627,46 @@ static inline void vma_init(struct vm_ar
INIT_LIST_HEAD(&vma->anon_vma_chain);
}
+/* Use when VMA is not part of the VMA tree and needs no locking */
+static inline void vm_flags_init(struct vm_area_struct *vma,
+ vm_flags_t flags)
+{
+ ACCESS_PRIVATE(vma, __vm_flags) = flags;
+}
+
+/* Use when VMA is part of the VMA tree and modifications need coordination */
+static inline void vm_flags_reset(struct vm_area_struct *vma,
+ vm_flags_t flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ vm_flags_init(vma, flags);
+}
+
+static inline void vm_flags_set(struct vm_area_struct *vma,
+ vm_flags_t flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ ACCESS_PRIVATE(vma, __vm_flags) |= flags;
+}
+
+static inline void vm_flags_clear(struct vm_area_struct *vma,
+ vm_flags_t flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ ACCESS_PRIVATE(vma, __vm_flags) &= ~flags;
+}
+
+/*
+ * Use only when the order of set/clear operations is unimportant, otherwise
+ * use vm_flags_{set|clear} explicitly.
+ */
+static inline void vm_flags_mod(struct vm_area_struct *vma,
+ vm_flags_t set, vm_flags_t clear)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ vm_flags_init(vma, (vma->vm_flags | set) & ~clear);
+}
+
static inline void vma_set_anonymous(struct vm_area_struct *vma)
{
vma->vm_ops = NULL;
--- a/include/linux/mm_types.h~mm-introduce-vma-vm_flags-wrapper-functions
+++ a/include/linux/mm_types.h
@@ -491,7 +491,15 @@ struct vm_area_struct {
* See vmf_insert_mixed_prot() for discussion.
*/
pgprot_t vm_page_prot;
- unsigned long vm_flags; /* Flags, see mm.h. */
+
+ /*
+ * Flags, see mm.h.
+ * To modify use vm_flags_{init|reset|set|clear|mod} functions.
+ */
+ union {
+ const vm_flags_t vm_flags;
+ vm_flags_t __private __vm_flags;
+ };
/*
* For areas with an address space and backing store,
_
Patches currently in -mm which might be from surenb@xxxxxxxxxx are
kernel-fork-convert-vma-assignment-to-a-memcpy.patch
mm-introduce-vma-vm_flags-wrapper-functions.patch
mm-replace-vm_locked_clear_mask-with-vm_locked_mask.patch
mm-replace-vma-vm_flags-direct-modifications-with-modifier-calls.patch
mm-replace-vma-vm_flags-indirect-modification-in-ksm_madvise.patch
mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn.patch
mm-export-dump_mm.patch
