On 1/15/19 9:55 AM, Jens Axboe wrote: > On 1/15/19 9:51 AM, Jonathan Corbet wrote: >> On Mon, 14 Jan 2019 19:55:20 -0700 >> Jens Axboe <axboe@xxxxxxxxx> wrote: >> >> So the [0/16] cover letter seems to have gone astray this time? > > It did go out, but I forgot to add a Subject line to it... > > https://marc.info/?l=linux-block&m=154752095709422&w=2 > > >>> The submission queue (SQ) and completion queue (CQ) rings are shared >>> between the application and the kernel. This eliminates the need to >>> copy data back and forth to submit and complete IO. >>> >>> IO submissions use the io_uring_sqe data structure, and completions >>> are generated in the form of io_uring_sqe data structures. The SQ >>> ring is an index into the io_uring_sqe array, which makes it possible >>> to submit a batch of IOs without them being contiguous in the ring. >>> The CQ ring is always contiguous, as completion events are inherently >>> unordered and can point to any io_uring_iocb. >>> >>> Two new system calls are added for this: >>> >>> io_uring_setup(entries, iovecs, params) >>> Sets up a context for doing async IO. On success, returns a file >>> descriptor that the application can mmap to gain access to the >>> SQ ring, CQ ring, and io_uring_iocbs. >> >> Looking at the code, it would appear that the "iovecs" parameter doesn't >> actually exist. > > Indeed, need to update that commit message. and io_uring_iocbs should > now be io_uring_sqes. > > The iovec/file registration is done through io_uring_register(2). Updated commit message which covers both this one, and the IORING_ENTER_GETEVENTS below. http://git.kernel.dk/cgit/linux-block/commit/?h=io_uring&id=d14a06629baef2b0701dbd01ac9c9066f73065ec -- Jens Axboe
