On 5/20/22 6:43 AM, Jason A. Donenfeld wrote:
> Hi Jens,
>
> On Thu, May 19, 2022 at 07:10:56PM -0600, Jens Axboe wrote:
>> On 5/19/22 7:00 PM, Jason A. Donenfeld wrote:
>>> Hi Jens,
>>>
>>> On Thu, May 19, 2022 at 06:56:12PM -0600, Jens Axboe wrote:
>>>> On 5/19/22 6:48 PM, Jason A. Donenfeld wrote:
>>>>> sendfile() returns -EINVAL even with your patches. Only splicing to pipes
>>>>> seems to work.
>>>>
>>>> Huh, that really should work. Are you trying to sendfile() to random? If
>>>> so, you need that last write_iter patch too, and add the splice_write as
>>>> I mentioned.
>>>
>>> No, I've only tried the read side so far. I made a little program:
>>>
>>> #include <sys/sendfile.h>
>>> #include <stdio.h>
>>>
>>> int main(int argc, char *argv[])
>>> {
>>> ssize_t s = sendfile(1, 0, NULL, 0xffff);
>>> fprintf(stderr, "ret: %zd\n", s);
>>> return 0;
>>> }
>>>
>>> Then I ran `./a.out < /dev/urandom > /dev/null`. Fails. OTOH, if I
>>> replace /dev/urandom with an ordinary file, it succeeds.
>>
>> Here's why, it's limited to regular files or block devices:
>>
>> if (unlikely(!S_ISREG(i_mode) && !S_ISBLK(i_mode)))
>> return -EINVAL;
>>
>> in splice_direct_to_actor().
>
> Indeed. Looks like that was your code from long long ago!
Yep I would not be surprised if that is the case!
> I posted
> https://lore.kernel.org/lkml/[email protected]/ to
> fix it if you'd like to review.
Not in my inbox, but you also used an email that hasn't been valid in 16
years :-)
But looks fine to me, we can open this up to character devices, don't
see an issue with that.
--
Jens Axboe
Hi Jens,
On Fri, May 20, 2022 at 06:49:45AM -0600, Jens Axboe wrote:
> > I posted
> > https://lore.kernel.org/lkml/[email protected]/ to
> > fix it if you'd like to review.
>
> Not in my inbox, but you also used an email that hasn't been valid in 16
> years :-)
>
> But looks fine to me, we can open this up to character devices, don't
> see an issue with that.
Whoops! I'll bounce it to you so you can provide a Reviewed-by for Al
over there.
Jason