strace of io_uring events?

[Andres Freund]

Hi,

On 2020-07-21 12:44:09 -0700, Andy Lutomirski wrote:
> Can you enlighten me?  I don't see any iov_iter_get_pages() calls or
> equivalents.  If an IO is punted, how does the data end up in the
> io_uring_enter() caller's mm?

For operations needing that io_op_def.needs_mm is true. Which is checked
by io_prep_async_work(), adding the current mm to req. On the wq side
io_wq_switch_mm() uses that mm when executing the queue entry.

Greetings,

Andres Freund