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authorJens Axboe <axboe@kernel.dk>2019-05-13 16:16:07 -0600
committerJens Axboe <axboe@kernel.dk>2019-05-13 16:16:07 -0600
commit0ba9503f793647bfd967da8083a2adf56621307c (patch)
treed0cb567953421723a4f93c6895f47081b48980ff /examples/link-cp.c
parent40c6f8454b86a5cd3bda63b41b9524ec162e9842 (diff)
downloadliburing-0ba9503f793647bfd967da8083a2adf56621307c.tar.gz
liburing-0ba9503f793647bfd967da8083a2adf56621307c.tar.bz2
Add link SQE support
Just a basic test case that does various forms of linked nops, and a sample bare bones copy program using linked reads and writes. Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'examples/link-cp.c')
-rw-r--r--examples/link-cp.c163
1 files changed, 163 insertions, 0 deletions
diff --git a/examples/link-cp.c b/examples/link-cp.c
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+++ b/examples/link-cp.c
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+/*
+ * Very basic proof-of-concept for doing a copy with linked SQEs. Needs a
+ * bit of error handling and short read love.
+ */
+#include <stdio.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+#include <inttypes.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include "../src/liburing.h"
+
+#define QD 64
+#define BS (32*1024)
+
+struct io_data {
+ struct iovec iov;
+};
+
+static int infd, outfd;
+
+static int setup_context(unsigned entries, struct io_uring *ring)
+{
+ int ret;
+
+ ret = io_uring_queue_init(entries, ring, 0);
+ if (ret < 0) {
+ fprintf(stderr, "queue_init: %s\n", strerror(-ret));
+ return -1;
+ }
+
+ return 0;
+}
+
+static int get_file_size(int fd, off_t *size)
+{
+ struct stat st;
+
+ if (fstat(fd, &st) < 0)
+ return -1;
+ if (S_ISREG(st.st_mode)) {
+ *size = st.st_size;
+ return 0;
+ } else if (S_ISBLK(st.st_mode)) {
+ unsigned long long bytes;
+
+ if (ioctl(fd, BLKGETSIZE64, &bytes) != 0)
+ return -1;
+
+ *size = bytes;
+ return 0;
+ }
+
+ return -1;
+}
+
+static int queue_rw_pair(struct io_uring *ring, off_t size, off_t offset)
+{
+ struct io_uring_sqe *sqe;
+ struct io_data *data;
+
+ data = malloc(size + sizeof(*data));
+ data->iov.iov_base = data + 1;
+ data->iov.iov_len = size;
+
+ sqe = io_uring_get_sqe(ring);
+ io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
+ sqe->flags |= IOSQE_IO_LINK;
+
+ sqe = io_uring_get_sqe(ring);
+ io_uring_prep_writev(sqe, outfd, &data->iov, 1, offset);
+ io_uring_sqe_set_data(sqe, data);
+ return 0;
+}
+
+static void handle_cqe(struct io_uring_cqe *cqe)
+{
+ struct io_data *data;
+
+ data = io_uring_cqe_get_data(cqe);
+ if (!data)
+ return;
+
+ free(data);
+}
+
+static int copy_file(struct io_uring *ring, off_t insize)
+{
+ struct io_uring_cqe *cqe;
+ size_t this_size;
+ off_t offset;
+ int inflight;
+
+ offset = 0;
+ inflight = 0;
+ while (insize) {
+ int has_inflight = inflight;
+
+ while (inflight < QD) {
+ this_size = BS;
+ if (this_size > insize)
+ this_size = insize;
+ queue_rw_pair(ring, this_size, offset);
+ offset += this_size;
+ insize -= this_size;
+ inflight += 2;
+ }
+
+ if (has_inflight != inflight)
+ io_uring_submit(ring);
+
+ while (inflight >= QD) {
+ int ret;
+
+ ret = io_uring_wait_cqe(ring, &cqe);
+ assert(ret >= 0);
+ handle_cqe(cqe);
+ inflight--;
+ }
+ }
+
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ struct io_uring ring;
+ off_t insize;
+ int ret;
+
+ if (argc < 3) {
+ printf("%s: infile outfile\n", argv[0]);
+ return 1;
+ }
+
+ infd = open(argv[1], O_RDONLY);
+ if (infd < 0) {
+ perror("open infile");
+ return 1;
+ }
+ outfd = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0644);
+ if (outfd < 0) {
+ perror("open outfile");
+ return 1;
+ }
+
+ if (setup_context(QD, &ring))
+ return 1;
+ if (get_file_size(infd, &insize))
+ return 1;
+
+ ret = copy_file(&ring, insize);
+
+ close(infd);
+ close(outfd);
+ io_uring_queue_exit(&ring);
+ return ret;
+}