Merge branch 'akpm' (patches from Andrew)

Merge even more updates from Andrew Morton:

 - a kernel-wide sweep of show_stack()

 - pagetable cleanups

 - abstract out accesses to mmap_sem - prep for mmap_sem scalability work

 - hch's user acess work

Subsystems affected by this patch series: debug, mm/pagemap, mm/maccess,
mm/documentation.

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (93 commits)
  include/linux/cache.h: expand documentation over __read_mostly
  maccess: return -ERANGE when probe_kernel_read() fails
  x86: use non-set_fs based maccess routines
  maccess: allow architectures to provide kernel probing directly
  maccess: move user access routines together
  maccess: always use strict semantics for probe_kernel_read
  maccess: remove strncpy_from_unsafe
  tracing/kprobes: handle mixed kernel/userspace probes better
  bpf: rework the compat kernel probe handling
  bpf:bpf_seq_printf(): handle potentially unsafe format string better
  bpf: handle the compat string in bpf_trace_copy_string better
  bpf: factor out a bpf_trace_copy_string helper
  maccess: unify the probe kernel arch hooks
  maccess: remove probe_read_common and probe_write_common
  maccess: rename strnlen_unsafe_user to strnlen_user_nofault
  maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault
  maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault
  maccess: update the top of file comment
  maccess: clarify kerneldoc comments
  maccess: remove duplicate kerneldoc comments
  ...

1 files changed, 4 insertions, 11 deletions

diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 8f18cf56b3dd..2b3afa354a90 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -10,7 +10,6 @@
 #include <linux/uaccess.h>
 #include <linux/sched/debug.h>
 #include <asm/current.h>
-#include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <arch.h>
 #include <as-layout.h>
@@ -27,9 +26,6 @@ int handle_page_fault(unsigned long address, unsigned long ip,
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;
 	int err = -EFAULT;
@@ -47,7 +43,7 @@ int handle_page_fault(unsigned long address, unsigned long ip,
 	if (is_user)
 		flags |= FAULT_FLAG_USER;
 retry:
-	down_read(&mm->mmap_sem);
+	mmap_read_lock(mm);
 	vma = find_vma(mm, address);
 	if (!vma)
 		goto out;
@@ -103,10 +99,7 @@ good_area:
 			}
 		}
 
-		pgd = pgd_offset(mm, address);
-		p4d = p4d_offset(pgd, address);
-		pud = pud_offset(p4d, address);
-		pmd = pmd_offset(pud, address);
+		pmd = pmd_off(mm, address);
 		pte = pte_offset_kernel(pmd, address);
 	} while (!pte_present(*pte));
 	err = 0;
@@ -123,7 +116,7 @@ good_area:
 #endif
 	flush_tlb_page(vma, address);
 out:
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 out_nosemaphore:
 	return err;
 
@@ -132,7 +125,7 @@ out_of_memory:
 	 * We ran out of memory, call the OOM killer, and return the userspace
 	 * (which will retry the fault, or kill us if we got oom-killed).
 	 */
-	up_read(&mm->mmap_sem);
+	mmap_read_unlock(mm);
 	if (!is_user)
 		goto out_nosemaphore;
 	pagefault_out_of_memory();