Re: [PATCH] Fix umove/umoven return value

[Ben N. <in...@bn...>]

On Tue, Feb 26, 2013 at 3:45 AM, Dmitry V. Levin <ld...@al...> wrote:
>> diff --git a/util.c b/util.c
>> index 405670e..af73f09 100644
>> --- a/util.c
>> +++ b/util.c
>> @@ -800,6 +800,8 @@ umoven(struct tcb *tcp, long addr, int len, char *laddr)
>>                               remote, 1,
>>                               /*flags:*/ 0
>>               );
>> +             if (r == len)
>> +                     return 0;
>
> This should rather be (r >= 0), and errno != ENOSYS shouldn't fall back to
> vm_readv_didnt_work case.

r >= 0 seems less safe than r == len.  What if you get less bytes than expected?

The errno != ENOSYS flow is unchanged, it was already like that.