From: Liam R. Howlett <Liam.Howlett@Oracle.com>
Date: Tue, 16 Mar 2021 19:57:18 +0000 (-0400)
Subject: cxl rcu fix
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=01babeb9e2e73962dd2dc3dff9c881085410fcf1;p=users%2Fjedix%2Flinux-maple.git

cxl rcu fix

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

diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c
index b1e5ded5ee903..b26aebb21b099 100644
--- a/drivers/misc/cxl/fault.c
+++ b/drivers/misc/cxl/fault.c
@@ -324,6 +324,7 @@ static void cxl_prefault_vma(struct cxl_context *ctx)
 
 	mas.tree = &mm->mm_mt;
 	mmap_read_lock(mm);
+	rcu_read_lock();
 	mas_for_each(&mas, vma, ULONG_MAX) {
 		for (ea = vma->vm_start; ea < vma->vm_end;
 				ea = next_segment(ea, slb.vsid)) {
@@ -338,6 +339,7 @@ static void cxl_prefault_vma(struct cxl_context *ctx)
 			last_esid = slb.esid;
 		}
 	}
+	rcu_read_unlock();
 	mmap_read_unlock(mm);
 
 	mmput(mm);