2021-06-02 06:54:32

by Kefeng Wang

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

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 <[email protected]>
---
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

2021-06-02 11:56:48

by Russell King (Oracle)

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

Hi,

On Wed, Jun 02, 2021 at 03:02:40PM +0800, Kefeng Wang wrote:
> 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 <[email protected]>

This looks fine to me. Please send it to the patch system (details in my
email signature.) Thanks.

--
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