On 4/11/23 8:41 AM, Jens Axboe wrote: > On 4/11/23 8:36?AM, David Ahern wrote: >> On 4/11/23 6:00 AM, Breno Leitao wrote: >>> I am not sure if avoiding io_uring details in network code is possible. >>> >>> The "struct proto"->uring_cmd callback implementation (tcp_uring_cmd() >>> in the TCP case) could be somewhere else, such as in the io_uring/ >>> directory, but, I think it might be cleaner if these implementations are >>> closer to function assignment (in the network subsystem). >>> >>> And this function (tcp_uring_cmd() for instance) is the one that I am >>> planning to map io_uring CMDs to ioctls. Such as SOCKET_URING_OP_SIOCINQ >>> -> SIOCINQ. >>> >>> Please let me know if you have any other idea in mind. >> >> I am not convinced that this io_uring_cmd is needed. This is one >> in-kernel subsystem calling into another, and there are APIs for that. >> All of this set is ioctl based and as Willem noted a little refactoring >> separates the get_user/put_user out so that in-kernel can call can be >> made with existing ops. > > How do you want to wire it up then? We can't use fops->unlocked_ioctl() > obviously, and we already have ->uring_cmd() for this purpose. > > I do think the right thing to do is have a common helper that returns > whatever value you want (or sets it), and split the ioctl parts into a > wrapper around that that simply copies in/out as needed. Then > ->uring_cmd() could call that, or you could some exported function that > does supports that. > > This works for the basic cases, though I do suspect we'll want to go > down the ->uring_cmd() at some point for more advanced cases or cases > that cannot sanely be done in an ioctl fashion. > My meta point is that there are uapis today to return this information to applications (and I suspect this is just the start of more networking changes - both data retrieval and adjusting settings). io_uring is wanting to do this on behalf of the application without a syscall. That makes io_uring yet another subsystem / component managing a socket. Any change to the networking stack required by io_uring should be usable by all other in-kernel socket owners or managers. ie., there is no reason for io_uring specific code here.
