Merge branch 'for-rmk/cacheflush-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/will/linux into devel-stable

arch/arm/kernel/traps.c

@@ -497,28 +497,64 @@ static int bad_syscall(int n, struct pt_regs *regs)
 	return regs->ARM_r0;
 }
 
+static long do_cache_op_restart(struct restart_block *);
+
+static inline int
+__do_cache_op(unsigned long start, unsigned long end)
+{
+	int ret;
+	unsigned long chunk = PAGE_SIZE;
+
+	do {
+		if (signal_pending(current)) {
+			struct thread_info *ti = current_thread_info();
+
+			ti->restart_block = (struct restart_block) {
+				.fn	= do_cache_op_restart,
+			};
+
+			ti->arm_restart_block = (struct arm_restart_block) {
+				{
+					.cache = {
+						.start	= start,
+						.end	= end,
+					},
+				},
+			};
+
+			return -ERESTART_RESTARTBLOCK;
+		}
+
+		ret = flush_cache_user_range(start, start + chunk);
+		if (ret)
+			return ret;
+
+		cond_resched();
+		start += chunk;
+	} while (start < end);
+
+	return 0;
+}
+
+static long do_cache_op_restart(struct restart_block *unused)
+{
+	struct arm_restart_block *restart_block;
+
+	restart_block = &current_thread_info()->arm_restart_block;
+	return __do_cache_op(restart_block->cache.start,
+			     restart_block->cache.end);
+}
+
 static inline int
 do_cache_op(unsigned long start, unsigned long end, int flags)
 {
-	struct mm_struct *mm = current->active_mm;
-	struct vm_area_struct *vma;
-
 	if (end < start || flags)
 		return -EINVAL;
 
-	down_read(&mm->mmap_sem);
-	vma = find_vma(mm, start);
-	if (vma && vma->vm_start < end) {
-		if (start < vma->vm_start)
-			start = vma->vm_start;
-		if (end > vma->vm_end)
-			end = vma->vm_end;
+	if (!access_ok(VERIFY_READ, start, end - start))
+		return -EFAULT;
 
-		up_read(&mm->mmap_sem);
-		return flush_cache_user_range(start, end);
-	}
-	up_read(&mm->mmap_sem);
-	return -EINVAL;
+	return __do_cache_op(start, end);
 }
 
 /*