As long as you're removing locks from prepend_name and complicating its
innards, I notice that each and every call site follows it by prepending
"/". How about moving that into prepend_name as well?
Also, if you happen to feel like it, you can delete the slash flag
and replace it with "bptr != *buffer".
Another small tweak would be to the global_root part of the code.
You could move the is_mounted(vfsmnt) test up, and combine the tail of
that code path with the regular exit. All you have to do is change
the !slash test to:
if (error>= 0&& bptr == *buffer) { /* Root directory */
if (--blen< 0)
error = -ENAMETOOLONG;
else
*--bptr = '/';
}
This modified form is no more code than an inlined copy of prepend(),
so we haven't actually slowed the fast path, but it avoids corrupting
the return value of 0/1/2 if possible.