[PATCH v2 1/7] ARM: mm: Rafactor the __do_page_fault()

Kefeng Wang
2021-06-02T06:53:51Z

Clean up the multiple goto statements and drops local variable
vm_fault_t fault, which will make the __do_page_fault() much
more readability.

No functional change.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
arch/arm/mm/fault.c | 34 +++++++++++++---------------------
1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index efa402025031..662ac3ca3c8a 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -205,35 +205,27 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
unsigned int flags, struct task_struct *tsk,
struct pt_regs *regs)
{
- struct vm_area_struct *vma;
- vm_fault_t fault;
-
- vma = find_vma(mm, addr);
- fault = VM_FAULT_BADMAP;
+ struct vm_area_struct *vma = find_vma(mm, addr);
if (unlikely(!vma))
- goto out;
- if (unlikely(vma->vm_start > addr))
- goto check_stack;
+ return VM_FAULT_BADMAP;
+
+ if (unlikely(vma->vm_start > addr)) {
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ return VM_FAULT_BADMAP;
+ if (addr < FIRST_USER_ADDRESS)
+ return VM_FAULT_BADMAP;
+ if (expand_stack(vma, addr))
+ return VM_FAULT_BADMAP;
+ }

/*
* Ok, we have a good vm_area for this
* memory access, so we can handle it.
*/
-good_area:
- if (access_error(fsr, vma)) {
- fault = VM_FAULT_BADACCESS;
- goto out;
- }
+ if (access_error(fsr, vma))
+ return VM_FAULT_BADACCESS;

return handle_mm_fault(vma, addr & PAGE_MASK, flags, regs);
-
-check_stack:
- /* Don't allow expansion below FIRST_USER_ADDRESS */
- if (vma->vm_flags & VM_GROWSDOWN &&
- addr >= FIRST_USER_ADDRESS && !expand_stack(vma, addr))
- goto good_area;
-out:
- return fault;
}

static int __kprobes
--
2.26.2