Re: aio: compat_ioctl issue?

[Michael Tokarev <mjt@tls.msk.ru>]

Michael Tokarev wrote:
> Jeff Moyer wrote:
> []
>>>>> I just come across a situation (next in a long row :)
>>>>> when on x86, 32bit userspace does not work with 64bit
>>>>> kernel.  This time this is about aio requests.
>> [snip]
[]
>> Could you maybe print out the values that are passed to io_getevents?
> 
> They were in my first email, here it goes again:
> 
> io_submit: lio_opcode=7 reqprio=0 iov=0x9cd7018{0xf5599000,4096}, niov=1, offset=0
> io_getevents: expected 4096 got -22 (EINVAL)
> 
> This is what gets passed to libaio -- strace here
> does not decode the arguments unfortunately.
[]
> My *guess* is that it handles read/write correctly but
> does not properly handle preadv/pwritev (opcode=7 is
> IO_CMD_PREADV as far as I can see).  That'll explain
> my "testcase" with Oracle which does not use preadv.

Actually, looking at the code in fs/compat.c, I don't see
where it converts iovecs.  Yes it converts iocbs, but for
readv/writev it also needs to convert iovecs.  Oh well,
that expects to be quite painful... :(

> Thanks!
> 
> /mjt
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