Update Linux to v5.10.157
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.157.tar.xz
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
Change-Id: I7b30d9e98d8c465d6b44de8e7433b4a40b3289ba
diff --git a/mm/rmap.c b/mm/rmap.c
index 14f84f7..e6f840b 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -89,7 +89,8 @@
anon_vma = kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
if (anon_vma) {
atomic_set(&anon_vma->refcount, 1);
- anon_vma->degree = 1; /* Reference for first vma */
+ anon_vma->num_children = 0;
+ anon_vma->num_active_vmas = 0;
anon_vma->parent = anon_vma;
/*
* Initialise the anon_vma root to point to itself. If called
@@ -197,6 +198,7 @@
anon_vma = anon_vma_alloc();
if (unlikely(!anon_vma))
goto out_enomem_free_avc;
+ anon_vma->num_children++; /* self-parent link for new root */
allocated = anon_vma;
}
@@ -206,8 +208,7 @@
if (likely(!vma->anon_vma)) {
vma->anon_vma = anon_vma;
anon_vma_chain_link(vma, avc, anon_vma);
- /* vma reference or self-parent link for new root */
- anon_vma->degree++;
+ anon_vma->num_active_vmas++;
allocated = NULL;
avc = NULL;
}
@@ -292,19 +293,19 @@
anon_vma_chain_link(dst, avc, anon_vma);
/*
- * Reuse existing anon_vma if its degree lower than two,
- * that means it has no vma and only one anon_vma child.
+ * Reuse existing anon_vma if it has no vma and only one
+ * anon_vma child.
*
- * Do not chose parent anon_vma, otherwise first child
- * will always reuse it. Root anon_vma is never reused:
+ * Root anon_vma is never reused:
* it has self-parent reference and at least one child.
*/
if (!dst->anon_vma && src->anon_vma &&
- anon_vma != src->anon_vma && anon_vma->degree < 2)
+ anon_vma->num_children < 2 &&
+ anon_vma->num_active_vmas == 0)
dst->anon_vma = anon_vma;
}
if (dst->anon_vma)
- dst->anon_vma->degree++;
+ dst->anon_vma->num_active_vmas++;
unlock_anon_vma_root(root);
return 0;
@@ -354,6 +355,7 @@
anon_vma = anon_vma_alloc();
if (!anon_vma)
goto out_error;
+ anon_vma->num_active_vmas++;
avc = anon_vma_chain_alloc(GFP_KERNEL);
if (!avc)
goto out_error_free_anon_vma;
@@ -374,7 +376,7 @@
vma->anon_vma = anon_vma;
anon_vma_lock_write(anon_vma);
anon_vma_chain_link(vma, avc, anon_vma);
- anon_vma->parent->degree++;
+ anon_vma->parent->num_children++;
anon_vma_unlock_write(anon_vma);
return 0;
@@ -406,7 +408,7 @@
* to free them outside the lock.
*/
if (RB_EMPTY_ROOT(&anon_vma->rb_root.rb_root)) {
- anon_vma->parent->degree--;
+ anon_vma->parent->num_children--;
continue;
}
@@ -414,7 +416,7 @@
anon_vma_chain_free(avc);
}
if (vma->anon_vma)
- vma->anon_vma->degree--;
+ vma->anon_vma->num_active_vmas--;
unlock_anon_vma_root(root);
/*
@@ -425,7 +427,8 @@
list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
struct anon_vma *anon_vma = avc->anon_vma;
- VM_WARN_ON(anon_vma->degree);
+ VM_WARN_ON(anon_vma->num_children);
+ VM_WARN_ON(anon_vma->num_active_vmas);
put_anon_vma(anon_vma);
list_del(&avc->same_vma);
@@ -1640,7 +1643,30 @@
/* MADV_FREE page check */
if (!PageSwapBacked(page)) {
- if (!PageDirty(page)) {
+ int ref_count, map_count;
+
+ /*
+ * Synchronize with gup_pte_range():
+ * - clear PTE; barrier; read refcount
+ * - inc refcount; barrier; read PTE
+ */
+ smp_mb();
+
+ ref_count = page_ref_count(page);
+ map_count = page_mapcount(page);
+
+ /*
+ * Order reads for page refcount and dirty flag
+ * (see comments in __remove_mapping()).
+ */
+ smp_rmb();
+
+ /*
+ * The only page refs must be one from isolation
+ * plus the rmap(s) (dropped by discard:).
+ */
+ if (ref_count == 1 + map_count &&
+ !PageDirty(page)) {
/* Invalidate as we cleared the pte */
mmu_notifier_invalidate_range(mm,
address, address + PAGE_SIZE);