Improving kernel string handling

long sys_foo(...)
{
long ret = 0;

/* ... */

ret = strscpy(dest, src, sizeof_dest);
if (ret < 0)
goto err;
/* ret now has the string length, saving a strlen() */

/* ... */

return ret;

err:
/* ...cleanup... */
return ret;
}

That is, in case of error, the value can be returned directly to userspace. That is a common design pattern in the kernel: if a function you called returns a negative value (indicating failure), abort what you were doing and pass that value up the stack.