| /* |
| * Check if the kernel sets IORING_SQ_CQ_OVERFLOW so that peeking events |
| * still enter the kernel to flush events, if the CQ side is overflown. |
| */ |
| #include <stdio.h> |
| #include <string.h> |
| #include <assert.h> |
| #include "liburing.h" |
| |
| static int test_cq_overflow(struct io_uring *ring) |
| { |
| struct io_uring_cqe *cqe; |
| struct io_uring_sqe *sqe; |
| unsigned flags; |
| int issued = 0; |
| int ret = 0; |
| |
| do { |
| sqe = io_uring_get_sqe(ring); |
| if (!sqe) { |
| fprintf(stderr, "get sqe failed\n"); |
| goto err; |
| } |
| 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); |
| |
| flags = IO_URING_READ_ONCE(*ring->sq.kflags); |
| if (!(flags & IORING_SQ_CQ_OVERFLOW)) { |
| fprintf(stdout, "OVERFLOW not set on -EBUSY, skipping\n"); |
| goto done; |
| } |
| |
| while (issued) { |
| ret = io_uring_peek_cqe(ring, &cqe); |
| if (ret) { |
| if (ret != -EAGAIN) { |
| fprintf(stderr, "peek completion failed: %s\n", |
| strerror(ret)); |
| break; |
| } |
| continue; |
| } |
| io_uring_cqe_seen(ring, cqe); |
| issued--; |
| } |
| |
| done: |
| return 0; |
| err: |
| return 1; |
| } |
| |
| int main(int argc, char *argv[]) |
| { |
| int ret; |
| struct io_uring ring; |
| struct io_uring_params p = { }; |
| |
| if (argc > 1) |
| return 0; |
| |
| ret = io_uring_queue_init_params(16, &ring, &p); |
| if (ret) { |
| fprintf(stderr, "ring setup failed: %d\n", ret); |
| return 1; |
| } |
| |
| if (!(p.features & IORING_FEAT_NODROP)) { |
| fprintf(stdout, "No overflow protection, skipped\n"); |
| return 0; |
| } |
| |
| ret = test_cq_overflow(&ring); |
| if (ret) { |
| fprintf(stderr, "test_cq_overflow failed\n"); |
| return 1; |
| } |
| |
| return 0; |
| } |