[patch v4] malloc: avoid need for tcache == NULL checks

[Florian Weimer]

* DJ Delorie:

> Florian Weimer <fweimer@redhat.com> writes:
>>> +  if (av)
>>> +    tcache = (tcache_perthread_struct *) _int_malloc (av, request2size (bytes));
>>
>> I think this is too long.
>
> It's 80 chars, tweaked.
>
>>> +  else
>>> +    tcache = (tcache_perthread_struct *) __libc_malloc2 (bytes);
>>>  
>>> -  if (tcache != NULL)
>>> +  if (tcache == NULL)
>>> +    {
>>> +      /* If the allocation failed, don't try again.  */
>>> +      tcache_set_disabled ();
>>> +    }
>>> +  else
>>
>> Already set above.
>
> No!  Setting tcache to the result of malloc undoes that and either
> leaves it active (non NULL) or NULL - and a NULL tcache is not the same
> as tcache_set_disabled, which sets tcache to a known pointer.

Thanks for the clarification.

Florian