}
EXPORT_SYMBOL(kmemdup);
+/**
+ * memdup_user - duplicate memory region from user space
+ *
+ * @src: source address in user space
+ * @len: number of bytes to copy
+ *
+ * Returns an ERR_PTR() on failure.
+ */
+void *memdup_user(const void __user *src, size_t len)
+{
+ void *p;
+
+ /*
+ * Always use GFP_KERNEL, since copy_from_user() can sleep and
+ * cause pagefault, which makes it pointless to use GFP_NOFS
+ * or GFP_ATOMIC.
+ */
+ p = kmalloc_track_caller(len, GFP_KERNEL);
+ if (!p)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(p, src, len)) {
+ kfree(p);
+ return ERR_PTR(-EFAULT);
+ }
+
+ return p;
+}
+EXPORT_SYMBOL(memdup_user);
+
/**
* __krealloc - like krealloc() but don't free @p.
* @p: object to reallocate memory for.
}
EXPORT_SYMBOL(krealloc);
+/**
+ * kzfree - like kfree but zero memory
+ * @p: object to free memory of
+ *
+ * The memory of the object @p points to is zeroed before freed.
+ * If @p is %NULL, kzfree() does nothing.
+ */
+void kzfree(const void *p)
+{
+ size_t ks;
+ void *mem = (void *)p;
+
+ if (unlikely(ZERO_OR_NULL_PTR(mem)))
+ return;
+ ks = ksize(mem);
+ memset(mem, 0, ks);
+ kfree(mem);
+}
+EXPORT_SYMBOL(kzfree);
+
/*
* strndup_user - duplicate an existing string from user space
* @s: The string to duplicate
mm->unmap_area = arch_unmap_area;
}
#endif
+
+int __attribute__((weak)) get_user_pages_fast(unsigned long start,
+ int nr_pages, int write, struct page **pages)
+{
+ struct mm_struct *mm = current->mm;
+ int ret;
+
+ down_read(&mm->mmap_sem);
+ ret = get_user_pages(current, mm, start, nr_pages,
+ write, 0, pages, NULL);
+ up_read(&mm->mmap_sem);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(get_user_pages_fast);