Update the fault handler to use a pseudo-vma when the original vma is
anonymous. This is in preparation to handling such faults with a fine
grained range lock in a later change.
Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
---
arch/x86/mm/fault.c | 20 +++++++++++++++++++-
1 file changed, 19 insertions(+), 1 deletion(-)
diff --git arch/x86/mm/fault.c arch/x86/mm/fault.c
index 700da3cc3db9..52333272e14e 100644
--- arch/x86/mm/fault.c
+++ arch/x86/mm/fault.c
@@ -1279,7 +1279,7 @@ void do_user_addr_fault(struct pt_regs *regs,
unsigned long address)
{
struct mm_lock_range *range;
- struct vm_area_struct *vma;
+ struct vm_area_struct pvma, *vma;
struct task_struct *tsk;
struct mm_struct *mm;
vm_fault_t fault, major = 0;
@@ -1423,6 +1423,23 @@ void do_user_addr_fault(struct pt_regs *regs,
return;
}
+ if (vma_is_anonymous(vma)) {
+ /*
+ * Allocate anon_vma if needed.
+ * This needs to operate on the vma of record.
+ */
+ fault = prepare_mm_fault(vma, flags);
+ if (fault)
+ goto got_fault;
+
+ /*
+ * Copy vma attributes into a pseudo-vma.
+ * This will be required when using fine grained locks.
+ */
+ pvma = *vma;
+ vma = &pvma;
+ }
+
/*
* If for any reason at all we couldn't handle the fault,
* make sure we exit gracefully rather than endlessly redo
@@ -1437,6 +1454,7 @@ void do_user_addr_fault(struct pt_regs *regs,
* FAULT_FLAG_USER|FAULT_FLAG_KILLABLE are both set in flags.
*/
fault = handle_mm_fault_range(vma, address, flags, range);
+got_fault:
major |= fault & VM_FAULT_MAJOR;
/*
--
2.25.0.341.g760bfbb309-goog
