user/sven/linux.git/include/uapi/linux/io_uring.h, branch v5.10.84

io_uring: provide IORING_ENTER_SQ_WAIT for SQPOLL SQ ring waits

2020-10-01T02:32:33Z

When using SQPOLL, applications can run into the issue of running out of SQ ring entries because the thread hasn't consumed them yet. The only option for dealing with that is checking later, or busy checking for the condition. Provide IORING_ENTER_SQ_WAIT if applications want to wait on this condition. Signed-off-by: Jens Axboe

io_uring: allow disabling rings during the creation

2020-10-01T02:32:33Z

This patch adds a new IORING_SETUP_R_DISABLED flag to start the rings disabled, allowing the user to register restrictions, buffers, files, before to start processing SQEs. When IORING_SETUP_R_DISABLED is set, SQE are not processed and SQPOLL kthread is not started. The restrictions registration are allowed only when the rings are disable to prevent concurrency issue while processing SQEs. The rings can be enabled using IORING_REGISTER_ENABLE_RINGS opcode with io_uring_register(2). Suggested-by: Jens Axboe Signed-off-by: Stefano Garzarella Reviewed-by: Kees Cook Signed-off-by: Jens Axboe

io_uring: add IOURING_REGISTER_RESTRICTIONS opcode

2020-10-01T02:32:33Z

The new io_uring_register(2) IOURING_REGISTER_RESTRICTIONS opcode permanently installs a feature allowlist on an io_ring_ctx. The io_ring_ctx can then be passed to untrusted code with the knowledge that only operations present in the allowlist can be executed. The allowlist approach ensures that new features added to io_uring do not accidentally become available when an existing application is launched on a newer kernel version. Currently is it possible to restrict sqe opcodes, sqe flags, and register opcodes. IOURING_REGISTER_RESTRICTIONS can only be made once. Afterwards it is not possible to change restrictions anymore. This prevents untrusted code from removing restrictions. Suggested-by: Stefan Hajnoczi Signed-off-by: Stefano Garzarella Reviewed-by: Kees Cook Signed-off-by: Jens Axboe

io_uring: use an enumeration for io_uring_register(2) opcodes

2020-10-01T02:32:33Z

The enumeration allows us to keep track of the last io_uring_register(2) opcode available. Behaviour and opcodes names don't change. Signed-off-by: Stefano Garzarella Reviewed-by: Kees Cook Signed-off-by: Jens Axboe

Merge branch 'io_uring-5.8' into for-5.9/io_uring

2020-07-24T18:53:31Z

Merge in io_uring-5.8 fixes, as changes/cleanups to how we do locked mem accounting require a fixup, and only one of the spots are noticed by git as the other merges cleanly. The flags fix from io_uring-5.8 also causes a merge conflict, the leak fix for recvmsg, the double poll fix, and the link failure locking fix. * io_uring-5.8: io_uring: fix lockup in io_fail_links() io_uring: fix ->work corruption with poll_add io_uring: missed req_init_async() for IOSQE_ASYNC io_uring: always allow drain/link/hardlink/async sqe flags io_uring: ensure double poll additions work with both request types io_uring: fix recvmsg memory leak with buffer selection io_uring: fix not initialised work->flags io_uring: fix missing msg_name assignment io_uring: account user memory freed when exit has been queued io_uring: fix memleak in io_sqe_files_register() io_uring: fix memleak in __io_sqe_files_update() io_uring: export cq overflow status to userspace Signed-off-by: Jens Axboe

io_uring: export cq overflow status to userspace

2020-07-09T01:17:06Z

For those applications which are not willing to use io_uring_enter() to reap and handle cqes, they may completely rely on liburing's io_uring_peek_cqe(), but if cq ring has overflowed, currently because io_uring_peek_cqe() is not aware of this overflow, it won't enter kernel to flush cqes, below test program can reveal this bug: static void test_cq_overflow(struct io_uring *ring) { struct io_uring_cqe *cqe; struct io_uring_sqe *sqe; int issued = 0; int ret = 0; do { sqe = io_uring_get_sqe(ring); if (!sqe) { fprintf(stderr, "get sqe failed\n"); break;; } ret = io_uring_submit(ring); if (ret <= 0) { if (ret != -EBUSY) fprintf(stderr, "sqe submit failed: %d\n", ret); break; } issued++; } while (ret > 0); assert(ret == -EBUSY); printf("issued requests: %d\n", issued); while (issued) { ret = io_uring_peek_cqe(ring, &cqe); if (ret) { if (ret != -EAGAIN) { fprintf(stderr, "peek completion failed: %s\n", strerror(ret)); break; } printf("left requets: %d\n", issued); continue; } io_uring_cqe_seen(ring, cqe); issued--; printf("left requets: %d\n", issued); } } int main(int argc, char *argv[]) { int ret; struct io_uring ring; ret = io_uring_queue_init(16, &ring, 0); if (ret) { fprintf(stderr, "ring setup failed: %d\n", ret); return 1; } test_cq_overflow(&ring); return 0; } To fix this issue, export cq overflow status to userspace by adding new IORING_SQ_CQ_OVERFLOW flag, then helper functions() in liburing, such as io_uring_peek_cqe, can be aware of this cq overflow and do flush accordingly. Signed-off-by: Xiaoguang Wang Signed-off-by: Jens Axboe

io_uring: change the poll type to be 32-bits

2020-06-22T02:44:00Z

poll events should be 32-bits to cover EPOLLEXCLUSIVE. Explicit word-swap the poll32_events for big endian to make sure the ABI is not changed. We call this feature IORING_FEAT_POLL_32BITS, applications who want to use EPOLLEXCLUSIVE should check the feature bit first. Signed-off-by: Jiufei Xue Signed-off-by: Jens Axboe

io_uring: add tee(2) support

2020-05-17T20:10:07Z

Add IORING_OP_TEE implementing tee(2) support. Almost identical to splice bits, but without offsets. Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe

io_uring: add IORING_CQ_EVENTFD_DISABLED to the CQ ring flags

2020-05-15T18:16:59Z

This new flag should be set/clear from the application to disable/enable eventfd notifications when a request is completed and queued to the CQ ring. Before this patch, notifications were always sent if an eventfd is registered, so IORING_CQ_EVENTFD_DISABLED is not set during the initialization. It will be up to the application to set the flag after initialization if no notifications are required at the beginning. Signed-off-by: Stefano Garzarella Signed-off-by: Jens Axboe

io_uring: add 'cq_flags' field for the CQ ring

2020-05-15T18:16:59Z

This patch adds the new 'cq_flags' field that should be written by the application and read by the kernel. This new field is available to the userspace application through 'cq_off.flags'. We are using 4-bytes previously reserved and set to zero. This means that if the application finds this field to zero, then the new functionality is not supported. In the next patch we will introduce the first flag available. Signed-off-by: Stefano Garzarella Signed-off-by: Jens Axboe