[rfc,-next,05/10] powerpc: mm: use try_vma_locked_page_fault()

Commit Message

Kefeng Wang July 13, 2023, 9:53 a.m. UTC

Use new try_vma_locked_page_fault() helper to simplify code.
No functional change intended.

Signed-off-by: Kefeng Wang <[e-mail]>
---
 arch/powerpc/mm/fault.c | 54 +++++++++++++++++------------------------
 1 file changed, 22 insertions(+), 32 deletions(-)

Patch

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 82954d0e6906..dd4832a3cf10 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -391,6 +391,23 @@  static int page_fault_is_bad(unsigned long err)
 #define page_fault_is_bad(__err)	((__err) & DSISR_BAD_FAULT_32S)
 #endif
 
+#ifdef CONFIG_PER_VMA_LOCK
+int arch_vma_check_access(struct vm_area_struct *vma,
+			  struct vm_locked_fault *vmlf)
+{
+	int is_exec = TRAP(vmlf->regs) == INTERRUPT_INST_STORAGE;
+	int is_write = page_fault_is_write(vmlf->fault_code);
+
+	if (unlikely(access_pkey_error(is_write, is_exec,
+				(vmlf->fault_code & DSISR_KEYFAULT), vma)))
+		return -EINVAL;
+
+	if (unlikely(access_error(is_write, is_exec, vma)))
+		return -EINVAL;
+	return 0;
+}
+#endif
+
 /*
  * For 600- and 800-family processors, the error_code parameter is DSISR
  * for a data fault, SRR1 for an instruction fault.
@@ -413,6 +430,7 @@  static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 	int is_write = page_fault_is_write(error_code);
 	vm_fault_t fault, major = 0;
 	bool kprobe_fault = kprobe_page_fault(regs, 11);
+	struct vm_locked_fault vmlf;
 
 	if (unlikely(debugger_fault_handler(regs) || kprobe_fault))
 		return 0;
@@ -469,41 +487,15 @@  static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 	if (is_exec)
 		flags |= FAULT_FLAG_INSTRUCTION;
 
-#ifdef CONFIG_PER_VMA_LOCK
-	if (!(flags & FAULT_FLAG_USER))
-		goto lock_mmap;
-
-	vma = lock_vma_under_rcu(mm, address);
-	if (!vma)
-		goto lock_mmap;
-
-	if (unlikely(access_pkey_error(is_write, is_exec,
-				       (error_code & DSISR_KEYFAULT), vma))) {
-		vma_end_read(vma);
-		goto lock_mmap;
-	}
-
-	if (unlikely(access_error(is_write, is_exec, vma))) {
-		vma_end_read(vma);
-		goto lock_mmap;
-	}
-
-	fault = handle_mm_fault(vma, address, flags | FAULT_FLAG_VMA_LOCK, regs);
-	if (!(fault & (VM_FAULT_RETRY | VM_FAULT_COMPLETED)))
-		vma_end_read(vma);
-
-	if (!(fault & VM_FAULT_RETRY)) {
-		count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
+	VM_LOCKED_FAULT_INIT(vmlf, mm, address, flags, 0, regs, error_code);
+	if (try_vma_locked_page_fault(&vmlf, &fault))
+		goto retry;
+	else if (!(fault | VM_FAULT_RETRY))
 		goto done;
-	}
-	count_vm_vma_lock_event(VMA_LOCK_RETRY);
 
 	if (fault_signal_pending(fault, regs))
 		return user_mode(regs) ? 0 : SIGBUS;
 
-lock_mmap:
-#endif /* CONFIG_PER_VMA_LOCK */
-
 	/* When running in the kernel we expect faults to occur only to
 	 * addresses in user space.  All other faults represent errors in the
 	 * kernel and should generate an OOPS.  Unfortunately, in the case of an
@@ -552,9 +544,7 @@  static int ___do_page_fault(struct pt_regs *regs, unsigned long address,
 
 	mmap_read_unlock(current->mm);
 
-#ifdef CONFIG_PER_VMA_LOCK
 done:
-#endif
 	if (unlikely(fault & VM_FAULT_ERROR))
 		return mm_fault_error(regs, address, fault);