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: Wed, 25 Jan 2023 15:35:49 -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/20230125233554.153109-3-surenb@xxxxxxxxxx
Signed-off-by: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/include/linux/mm.h~mm-introduce-vma-vm_flags-wrapper-functions
+++ a/include/linux/mm.h
@@ -627,6 +627,43 @@ 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 init_vm_flags(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 reset_vm_flags(struct vm_area_struct *vma,
+ vm_flags_t flags)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ init_vm_flags(vma, flags);
+}
+
+static inline void set_vm_flags(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 clear_vm_flags(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 mod_vm_flags(struct vm_area_struct *vma,
+ vm_flags_t set, vm_flags_t clear)
+{
+ mmap_assert_write_locked(vma->vm_mm);
+ ACCESS_PRIVATE(vma, __vm_flags) |= set;
+ ACCESS_PRIVATE(vma, __vm_flags) &= ~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 {init|reset|set|clear|mod}_vm_flags() 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-mod_vm_flags_nolock-and-use-it-in-untrack_pfn.patch
mm-export-dump_mm.patch
