Add support for IORING_REGISTER_PBUF_STATUS Basic support for querying the provided ring buffer head, and a helper that returns the number of available entries. Includes a basic test case as well. Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/src/include/liburing.h b/src/include/liburing.h index e66c75c..b3f8230 100644 --- a/src/include/liburing.h +++ b/src/include/liburing.h
@@ -239,6 +239,7 @@ int io_uring_register_buf_ring(struct io_uring *ring, struct io_uring_buf_reg *reg, unsigned int flags); int io_uring_unregister_buf_ring(struct io_uring *ring, int bgid); +int io_uring_buf_ring_head(struct io_uring *ring, int buf_group, unsigned *head); int io_uring_register_sync_cancel(struct io_uring *ring, struct io_uring_sync_cancel_reg *reg); @@ -1488,6 +1489,20 @@ __io_uring_buf_ring_cq_advance(ring, br, count, count); } +IOURINGINLINE int io_uring_buf_ring_available(struct io_uring *ring, + struct io_uring_buf_ring *br, + unsigned short bgid) +{ + unsigned head; + int ret; + + ret = io_uring_buf_ring_head(ring, bgid, &head); + if (ret) + return ret; + + return br->tail - head; +} + #ifndef LIBURING_INTERNAL IOURINGINLINE struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring) {
diff --git a/src/include/liburing/io_uring.h b/src/include/liburing/io_uring.h index dfeb5fa..2a473d1 100644 --- a/src/include/liburing/io_uring.h +++ b/src/include/liburing/io_uring.h
@@ -562,6 +562,9 @@ /* register a range of fixed file slots for automatic slot allocation */ IORING_REGISTER_FILE_ALLOC_RANGE = 25, + /* return status information for a buffer group */ + IORING_REGISTER_PBUF_STATUS = 26, + /* this goes last */ IORING_REGISTER_LAST, @@ -688,6 +691,13 @@ __u64 resv[3]; }; +/* argument for IORING_REGISTER_PBUF_STATUS */ +struct io_uring_buf_status { + __u32 buf_group; /* input */ + __u32 head; /* output */ + __u32 resv[8]; +}; + /* * io_uring_restriction->opcode values */
diff --git a/src/register.c b/src/register.c index bf010b0..782736d 100644 --- a/src/register.c +++ b/src/register.c
@@ -326,6 +326,20 @@ return do_register(ring, IORING_UNREGISTER_PBUF_RING, ®, 1); } +int io_uring_buf_ring_head(struct io_uring *ring, int buf_group, unsigned *head) +{ + struct io_uring_buf_status buf_status = { + .buf_group = buf_group, + }; + int ret; + + ret = do_register(ring, IORING_REGISTER_PBUF_STATUS, &buf_status, 1); + if (ret) + return ret; + *head = buf_status.head; + return 0; +} + int io_uring_register_sync_cancel(struct io_uring *ring, struct io_uring_sync_cancel_reg *reg) {
diff --git a/test/Makefile b/test/Makefile index 25abd54..9ccc36e 100644 --- a/test/Makefile +++ b/test/Makefile
@@ -155,6 +155,7 @@ register-restrictions.c \ rename.c \ ringbuf-read.c \ + ringbuf-status.c \ ring-leak2.c \ ring-leak.c \ rsrc_tags.c \
diff --git a/test/ringbuf-status.c b/test/ringbuf-status.c new file mode 100644 index 0000000..b36216e --- /dev/null +++ b/test/ringbuf-status.c
@@ -0,0 +1,182 @@ +/* SPDX-License-Identifier: MIT */ +/* + * Description: test reading provided ring buf head + * + */ +#include <errno.h> +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> + +#include "liburing.h" +#include "helpers.h" + +#define BUF_SIZE 32 +#define NR_BUFS 8 +#define FSIZE (BUF_SIZE * NR_BUFS) + +#define BR_MASK (NR_BUFS - 1) +#define BGID 1 + +static int no_buf_ring; +static int no_buf_ring_status; + +static int test(int invalid) +{ + struct io_uring_sqe *sqe; + struct io_uring_cqe *cqe; + struct io_uring ring; + struct io_uring_buf_ring *br; + int ret, i, fds[2]; + unsigned head; + char *buf; + void *ptr; + char output[16]; + + memset(output, 0x55, sizeof(output)); + + ret = io_uring_queue_init(NR_BUFS, &ring, 0); + if (ret) { + fprintf(stderr, "ring setup failed: %d\n", ret); + return 1; + } + + if (pipe(fds) < 0) { + perror("pipe"); + return T_EXIT_FAIL; + } + + if (posix_memalign((void **) &buf, 4096, FSIZE)) + return 1; + + br = io_uring_setup_buf_ring(&ring, NR_BUFS, BGID, 0, &ret); + if (!br) { + if (ret == -EINVAL) { + no_buf_ring = 1; + return 0; + } + fprintf(stderr, "Buffer ring register failed %d\n", ret); + return 1; + } + + ptr = buf; + for (i = 0; i < NR_BUFS; i++) { + io_uring_buf_ring_add(br, ptr, BUF_SIZE, i + 1, BR_MASK, i); + ptr += BUF_SIZE; + } + io_uring_buf_ring_advance(br, NR_BUFS); + + /* head should be zero at this point */ + head = 1; + if (!invalid) + ret = io_uring_buf_ring_head(&ring, BGID, &head); + else + ret = io_uring_buf_ring_head(&ring, BGID + 10, &head); + if (ret) { + if (ret == -EINVAL) { + no_buf_ring_status = 1; + return T_EXIT_SKIP; + } + if (invalid && ret == -ENOENT) + return T_EXIT_PASS; + fprintf(stderr, "buf_ring_head: %d\n", ret); + return T_EXIT_FAIL; + } + if (invalid) { + fprintf(stderr, "lookup of bad group id succeeded\n"); + return T_EXIT_FAIL; + } + if (head != 0) { + fprintf(stderr, "bad head %d\n", head); + return T_EXIT_FAIL; + } + + ret = io_uring_buf_ring_available(&ring, br, BGID); + if (ret != NR_BUFS) { + fprintf(stderr, "ring available %d\n", ret); + return T_EXIT_FAIL; + } + + sqe = io_uring_get_sqe(&ring); + io_uring_prep_read(sqe, fds[0], NULL, BUF_SIZE, i * BUF_SIZE); + sqe->buf_group = BGID; + sqe->flags |= IOSQE_BUFFER_SELECT; + sqe->user_data = 1; + + ret = io_uring_submit(&ring); + if (ret != 1) { + fprintf(stderr, "submit: %d\n", ret); + return T_EXIT_FAIL; + } + + /* head should still be zero at this point, no buffers consumed */ + head = 1; + ret = io_uring_buf_ring_head(&ring, BGID, &head); + if (head != 0) { + fprintf(stderr, "bad head after submit %d\n", head); + return T_EXIT_FAIL; + } + + ret = write(fds[1], output, sizeof(output)); + if (ret != sizeof(output)) { + fprintf(stderr, "pipe buffer write %d\n", ret); + return T_EXIT_FAIL; + } + + ret = io_uring_wait_cqe(&ring, &cqe); + if (ret) { + fprintf(stderr, "wait cqe failed %d\n", ret); + return T_EXIT_FAIL; + } + if (cqe->res != sizeof(output)) { + fprintf(stderr, "cqe res %d\n", cqe->res); + return T_EXIT_FAIL; + } + if (!(cqe->flags & IORING_CQE_F_BUFFER)) { + fprintf(stderr, "no buffer selected\n"); + return T_EXIT_FAIL; + } + io_uring_cqe_seen(&ring, cqe); + + /* head should now be one, we consumed a buffer */ + ret = io_uring_buf_ring_head(&ring, BGID, &head); + if (head != 1) { + fprintf(stderr, "bad head after cqe %d\n", head); + return T_EXIT_FAIL; + } + + ret = io_uring_buf_ring_available(&ring, br, BGID); + if (ret != NR_BUFS - 1) { + fprintf(stderr, "ring available %d\n", ret); + return T_EXIT_FAIL; + } + + close(fds[0]); + close(fds[1]); + free(buf); + io_uring_queue_exit(&ring); + return T_EXIT_PASS; +} + +int main(int argc, char *argv[]) +{ + int ret; + + ret = test(0); + if (ret == T_EXIT_FAIL) { + fprintf(stderr, "test 0 failed\n"); + return T_EXIT_FAIL; + } + if (no_buf_ring || no_buf_ring_status) + return T_EXIT_SKIP; + + ret = test(1); + if (ret == T_EXIT_FAIL) { + fprintf(stderr, "test 1 failed\n"); + return T_EXIT_FAIL; + } + + return T_EXIT_PASS; +}