From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Fri, 24 Jul 2020 17:32:30 +0000 (-0400)
Subject: kernel/fork: Convert dup_mmap to use maple tree
X-Git-Tag: howlett/maple/20200727~1
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7fd58758bd618605182f7b22ff9942a947539a1c;p=users%2Fjedix%2Flinux-maple.git

kernel/fork: Convert dup_mmap to use maple tree

Use the maple tree iterator to duplicate the mm_struct trees.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
---

diff --git a/kernel/fork.c b/kernel/fork.c
index 8b38eebf7e10..04b480e532b2 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -489,6 +489,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 	struct rb_node **rb_link, *rb_parent;
 	int retval;
 	unsigned long charge;
+	MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
 	LIST_HEAD(uf);
 
 	uprobe_start_dup_mmap();
@@ -522,9 +523,17 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 		goto out;
 
 	prev = NULL;
-	for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
+
+	mas_lock(&old_mas);
+	mas_for_each(&old_mas, mpnt, ULONG_MAX) {
 		struct file *file;
 
+		if (xa_is_zero(mpnt))
+			continue;
+
+		mas_pause(&old_mas);
+		mas_unlock(&old_mas);
+
 		if (mpnt->vm_flags & VM_DONTCOPY) {
 			vm_stat_account(mm, mpnt->vm_flags, -vma_pages(mpnt));
 			continue;
@@ -616,7 +625,11 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
 
 		if (retval)
 			goto out;
+
+		mas_lock(&old_mas);
 	}
+	mas_unlock(&old_mas);
+
 	/* a new mm has just been created */
 	retval = arch_dup_mmap(oldmm, mm);
 out: