On 2020/04/19 6:45, Bart Van Assche wrote: > On 4/17/20 5:15 AM, Johannes Thumshirn wrote: >> Synchronous direct I/O to a sequential write only zone can be issued using >> the new REQ_OP_ZONE_APPEND request operation. As dispatching multiple >> BIOs can potentially result in reordering, we cannot support asynchronous >> IO via this interface. >> >> We also can only dispatch up to queue_max_zone_append_sectors() via the >> new zone-append method and have to return a short write back to user-space >> in case an IO larger than queue_max_zone_append_sectors() has been issued. > > Is this patch the only patch that adds a user space interface through > which REQ_OP_ZONE_APPEND operations can be submitted? Has it been > considered to make it possible to submit REQ_OP_ZONE_APPEND operations > through the asynchronous I/O mechanism? Yes, we have looked into it. We do have some hack-ish code working for that. For the initial feature post though, we didn't want to add that part to facilitate reviews and also because we need more work to cleanly handle zone append in the aio code (that code is written assuming that BIOs can always be split and so never returns short writes). > > Thanks, > > Bart. > -- Damien Le Moal Western Digital Research
