From: Liam R. Howlett <Liam.Howlett@oracle.com>
Date: Fri, 16 Jun 2023 15:34:44 +0000 (-0400)
Subject: update to use upgrade_mmap_lock_carefully()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=6d6c725418b522d97cdd878dc358916a344a2c73;p=users%2Fjedix%2Flinux-maple.git

update to use upgrade_mmap_lock_carefully()

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

diff --git a/mm/memory.c b/mm/memory.c
index c291511c3155..cb35e52bbd1e 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5331,6 +5331,7 @@ struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm,
 			unsigned long addr, struct pt_regs *regs)
 {
 	struct vm_area_struct *vma;
+	int err;
 
 	if (!get_mmap_lock_carefully(mm, regs))
 		return NULL;
@@ -5343,20 +5344,25 @@ struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm,
 	 * Well, dang. We might still be successful, but only
 	 * if we can extend a vma to do so.
 	 */
-	if (!vma || !(vma->vm_flags & VM_GROWSDOWN)) {
+	if (unlikely(!vma)) {
 		mmap_read_unlock(mm);
 		return NULL;
 	}
-
-	if (!upgrade_mmap_lock_carefully(mm, regs))
-		return NULL;
-
-	vma = find_extend_vma(mm, addr);
-	if (!vma) {
-		mmap_write_unlock(mm);
-		return NULL;
+	err = expand_stack(vma, addr, false);
+	if (unlikely(err)){
+		if (err != -EAGAIN) {
+			mmap_read_unlock(mm);
+			return NULL;
+		}
+		if (!upgrade_mmap_lock_carefully(mm, regs))
+			return NULL;
+		vma = find_vma(mm, addr);
+		if (!vma || expand_stack(vma, addr, true)) {
+			mmap_write_unlock(mm);
+			return NULL;
+		}
+		mmap_write_downgrade(mm);
 	}
-	mmap_write_downgrade(mm);
 	return vma;
 }
 #endif
diff --git a/mm/mmap.c b/mm/mmap.c
index 2f560181148d..11d6af071c4d 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2193,16 +2193,18 @@ struct vm_area_struct *find_extend_vma_locked(struct mm_struct *mm,
 		return vma;
 	start = vma->vm_start;
 	err = expand_stack(vma, addr, write_locked);
-	if (unlikely(err == -EAGAIN)) {
-		mmap_read_unlock(mm);
-		mmap_write_lock(mm);
+	if (unlikely(err)) {
+		if (err != -EAGAIN)
+			return NULL;
+		if (!upgrade_mmap_lock_carefully(mm, NULL))
+			return NULL;
 		vma = find_vma(mm, addr);
-		if (vma)
-			err = expand_stack(vma, addr, true);
+		if (!vma || expand_stack(vma, addr, true)) {
+			mmap_write_downgrade(mm);
+			return NULL;
+		}
 		mmap_write_downgrade(mm);
 	}
-	if (err)
-		return NULL;
 	if (vma->vm_flags & VM_LOCKED)
 		populate_vma_page_range(vma, addr, start, NULL);
 	return vma;