[PATCH v2 05/13] mm: prefer mm->def_vma_flags in mm logic

[Lorenzo Stoakes <ljs@kernel.org>]

Currently mm->def_flags (of type vm_flags_t) is union'd with
mm->def_vma_flags (of type vma_flags_t).

As part of the effort to convert vm_flags_t usage to vma_flags_t (in order
to no longer be arbitrarily limited to a system word size for VMA flags),
prefer mm->def_vma_flags to mm->def_flags throughout the mm logic.

We update dump_mm() to use the %*pb format which means we make no
assumption about the number of VMA flag bits on output when outputting
default VMA flags.

No functional change intended.

Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
---
 mm/debug.c |  5 +++--
 mm/mlock.c | 13 +++++++------
 mm/mmap.c  | 11 ++++++-----
 mm/vma.c   |  2 +-
 4 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/mm/debug.c b/mm/debug.c
index 497654b36f1a..9a0297b3988d 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -197,7 +197,7 @@ void dump_mm(const struct mm_struct *mm)
 		"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
 #endif
 		"tlb_flush_pending %d\n"
-		"def_flags: %#lx(%pGv)\n",
+		"def_flags: %*pb(%pGv)\n",
 
 		mm, mm->task_size,
 		mm->mmap_base, mm->mmap_legacy_base,
@@ -226,7 +226,8 @@ void dump_mm(const struct mm_struct *mm)
 		mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
 #endif
 		atomic_read(&mm->tlb_flush_pending),
-		mm->def_flags, &mm->def_flags
+		NUM_VMA_FLAG_BITS, mm->def_vma_flags.__vma_flags,
+		&mm->def_vma_flags
 	);
 }
 EXPORT_SYMBOL(dump_mm);
diff --git a/mm/mlock.c b/mm/mlock.c
index 97e49038d8d3..34ffa954006f 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -699,26 +699,27 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
 
 /*
  * Take the MCL_* flags passed into mlockall (or 0 if called from munlockall)
- * and translate into the appropriate modifications to mm->def_flags and/or the
- * flags for all current VMAs.
+ * and translate into the appropriate modifications to mm->def_vma_flags and/or
+ * the flags for all current VMAs.
  *
  * There are a couple of subtleties with this.  If mlockall() is called multiple
  * times with different flags, the values do not necessarily stack.  If mlockall
  * is called once including the MCL_FUTURE flag and then a second time without
- * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags.
+ * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_vma_flags.
  */
 static int apply_mlockall_flags(int flags)
 {
 	VMA_ITERATOR(vmi, current->mm, 0);
+	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma, *prev = NULL;
 	vm_flags_t to_add = 0;
 
-	current->mm->def_flags &= ~VM_LOCKED_MASK;
+	vma_flags_clear_mask(&mm->def_vma_flags, VMA_LOCKED_MASK);
 	if (flags & MCL_FUTURE) {
-		current->mm->def_flags |= VM_LOCKED;
+		vma_flags_set(&mm->def_vma_flags, VMA_LOCKED_BIT);
 
 		if (flags & MCL_ONFAULT)
-			current->mm->def_flags |= VM_LOCKONFAULT;
+			vma_flags_set(&mm->def_vma_flags, VMA_LOCKONFAULT_BIT);
 
 		if (!(flags & MCL_CURRENT))
 			goto out;
diff --git a/mm/mmap.c b/mm/mmap.c
index 39d33f3a55c2..ae9a5018e20e 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -102,15 +102,16 @@ void vma_set_page_prot(struct vm_area_struct *vma)
  */
 static int check_brk_limits(unsigned long addr, unsigned long len)
 {
+	const struct mm_struct *mm = current->mm;
+	const bool is_def_locked =
+		vma_flags_test(&mm->def_vma_flags, VMA_LOCKED_BIT);
 	unsigned long mapped_addr;
 
 	mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED);
 	if (IS_ERR_VALUE(mapped_addr))
 		return mapped_addr;
 
-	return mlock_future_ok(current->mm,
-			      current->mm->def_flags & VM_LOCKED, len)
-		? 0 : -EAGAIN;
+	return mlock_future_ok(mm, is_def_locked, len) ? 0 : -EAGAIN;
 }
 
 SYSCALL_DEFINE1(brk, unsigned long, brk)
@@ -197,7 +198,7 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
 		goto out;
 
 	mm->brk = brk;
-	if (mm->def_flags & VM_LOCKED)
+	if (vma_flags_test(&mm->def_vma_flags, VMA_LOCKED_BIT))
 		populate = true;
 
 success:
@@ -1247,7 +1248,7 @@ int vm_brk_flags(unsigned long addr, unsigned long request, bool is_exec)
 
 	vma = vma_prev(&vmi);
 	ret = do_brk_flags(&vmi, vma, addr, len, vma_flags);
-	populate = ((mm->def_flags & VM_LOCKED) != 0);
+	populate = vma_flags_test(&mm->def_vma_flags, VMA_LOCKED_BIT);
 	mmap_write_unlock(mm);
 	userfaultfd_unmap_complete(mm, &uf);
 	if (populate && !ret)
diff --git a/mm/vma.c b/mm/vma.c
index 70b08c76ea2f..1f443d979a7d 100644
--- a/mm/vma.c
+++ b/mm/vma.c
@@ -3426,7 +3426,7 @@ struct vm_area_struct *__install_special_mapping(
 	if (unlikely(vma == NULL))
 		return ERR_PTR(-ENOMEM);
 
-	vm_flags |= mm->def_flags | VM_DONTEXPAND;
+	vm_flags |= vma_flags_to_legacy(mm->def_vma_flags) | VM_DONTEXPAND;
 	if (pgtable_supports_soft_dirty())
 		vm_flags |= VM_SOFTDIRTY;
 	vm_flags_init(vma, vm_flags & ~VM_LOCKED_MASK);

-- 
2.55.0