+++ /dev/null
-/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
- *
- * lttng-probe-user.c
- *
- * Copyright (C) 2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- */
-
-#include <linux/uaccess.h>
-#include <linux/module.h>
-#include <probes/lttng-probe-user.h>
-
-/*
- * Calculate string length. Include final null terminating character if there is
- * one, or ends at first fault. Disabling page faults ensures that we can safely
- * call this from pretty much any context, including those where the caller
- * holds mmap_sem, or any lock which nests in mmap_sem.
- */
-long lttng_strlen_user_inatomic(const char *addr)
-{
- long count = 0;
- mm_segment_t old_fs;
-
- if (!addr)
- return 0;
-
- old_fs = get_fs();
- set_fs(KERNEL_DS);
- pagefault_disable();
- for (;;) {
- char v;
- unsigned long ret;
-
- if (unlikely(!access_ok(VERIFY_READ,
- (__force const char __user *) addr,
- sizeof(v))))
- break;
- ret = __copy_from_user_inatomic(&v,
- (__force const char __user *)(addr),
- sizeof(v));
- if (unlikely(ret > 0))
- break;
- count++;
- if (unlikely(!v))
- break;
- addr++;
- }
- pagefault_enable();
- set_fs(old_fs);
- return count;
-}
-EXPORT_SYMBOL_GPL(lttng_strlen_user_inatomic);