[PATCH 1/1] io_uring: kill io_uring userspace examples

[PATCH 1/1] io_uring: kill io_uring userspace examples

[Pavel Begunkov]

There are tons of io_uring tests and examples in liburing and on the
Internet. If you're looking for a benchmark, io_uring-bench.c is just an
acutely outdated version of fio/io_uring. And for basic condensed init
template for likes of selftests take a peek at io_uring_zerocopy_tx.c.

Kill tools/io_uring/, it's a burden keeping it here.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
 MAINTAINERS                     |   1 -
 tools/io_uring/Makefile         |  18 -
 tools/io_uring/README           |  29 --
 tools/io_uring/barrier.h        |  16 -
 tools/io_uring/io_uring-bench.c | 592 --------------------------------
 tools/io_uring/io_uring-cp.c    | 283 ---------------
 tools/io_uring/liburing.h       | 187 ----------
 tools/io_uring/queue.c          | 156 ---------
 tools/io_uring/setup.c          | 107 ------
 tools/io_uring/syscall.c        |  52 ---
 10 files changed, 1441 deletions(-)
 delete mode 100644 tools/io_uring/Makefile
 delete mode 100644 tools/io_uring/README
 delete mode 100644 tools/io_uring/barrier.h
 delete mode 100644 tools/io_uring/io_uring-bench.c
 delete mode 100644 tools/io_uring/io_uring-cp.c
 delete mode 100644 tools/io_uring/liburing.h
 delete mode 100644 tools/io_uring/queue.c
 delete mode 100644 tools/io_uring/setup.c
 delete mode 100644 tools/io_uring/syscall.c

diff --git a/MAINTAINERS b/MAINTAINERS
index aee340630eca..2ce167bd0ab4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10920,7 +10920,6 @@ F:	include/linux/io_uring_types.h
 F:	include/trace/events/io_uring.h
 F:	include/uapi/linux/io_uring.h
 F:	io_uring/
-F:	tools/io_uring/
 
 IPMI SUBSYSTEM
 M:	Corey Minyard <minyard@acm.org>
diff --git a/tools/io_uring/Makefile b/tools/io_uring/Makefile
deleted file mode 100644
index 00f146c54c53..000000000000
--- a/tools/io_uring/Makefile
+++ /dev/null
@@ -1,18 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-# Makefile for io_uring test tools
-CFLAGS += -Wall -Wextra -g -D_GNU_SOURCE
-LDLIBS += -lpthread
-
-all: io_uring-cp io_uring-bench
-%: %.c
-	$(CC) $(CFLAGS) -o $@ $^
-
-io_uring-bench: syscall.o io_uring-bench.o
-	$(CC) $(CFLAGS) -o $@ $^ $(LDLIBS)
-
-io_uring-cp: setup.o syscall.o queue.o
-
-clean:
-	$(RM) io_uring-cp io_uring-bench *.o
-
-.PHONY: all clean
diff --git a/tools/io_uring/README b/tools/io_uring/README
deleted file mode 100644
index 67fd70115cff..000000000000
--- a/tools/io_uring/README
+++ /dev/null
@@ -1,29 +0,0 @@
-This directory includes a few programs that demonstrate how to use io_uring
-in an application. The examples are:
-
-io_uring-cp
-	A very basic io_uring implementation of cp(1). It takes two
-	arguments, copies the first argument to the second. This example
-	is part of liburing, and hence uses the simplified liburing API
-	for setting up an io_uring instance, submitting IO, completing IO,
-	etc. The support functions in queue.c and setup.c are straight
-	out of liburing.
-
-io_uring-bench
-	Benchmark program that does random reads on a number of files. This
-	app demonstrates the various features of io_uring, like fixed files,
-	fixed buffers, and polled IO. There are options in the program to
-	control which features to use. Arguments is the file (or files) that
-	io_uring-bench should operate on. This uses the raw io_uring
-	interface.
-
-liburing can be cloned with git here:
-
-	git://git.kernel.dk/liburing
-
-and contains a number of unit tests as well for testing io_uring. It also
-comes with man pages for the three system calls.
-
-Fio includes an io_uring engine, you can clone fio here:
-
-	git://git.kernel.dk/fio
diff --git a/tools/io_uring/barrier.h b/tools/io_uring/barrier.h
deleted file mode 100644
index ef00f6722ba9..000000000000
--- a/tools/io_uring/barrier.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#ifndef LIBURING_BARRIER_H
-#define LIBURING_BARRIER_H
-
-#if defined(__x86_64) || defined(__i386__)
-#define read_barrier()	__asm__ __volatile__("":::"memory")
-#define write_barrier()	__asm__ __volatile__("":::"memory")
-#else
-/*
- * Add arch appropriate definitions. Be safe and use full barriers for
- * archs we don't have support for.
- */
-#define read_barrier()	__sync_synchronize()
-#define write_barrier()	__sync_synchronize()
-#endif
-
-#endif
diff --git a/tools/io_uring/io_uring-bench.c b/tools/io_uring/io_uring-bench.c
deleted file mode 100644
index 7703f0118385..000000000000
--- a/tools/io_uring/io_uring-bench.c
+++ /dev/null
@@ -1,592 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Simple benchmark program that uses the various features of io_uring
- * to provide fast random access to a device/file. It has various
- * options that are control how we use io_uring, see the OPTIONS section
- * below. This uses the raw io_uring interface.
- *
- * Copyright (C) 2018-2019 Jens Axboe
- */
-#include <stdio.h>
-#include <errno.h>
-#include <assert.h>
-#include <stdlib.h>
-#include <stddef.h>
-#include <signal.h>
-#include <inttypes.h>
-
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/ioctl.h>
-#include <sys/syscall.h>
-#include <sys/resource.h>
-#include <sys/mman.h>
-#include <sys/uio.h>
-#include <linux/fs.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <string.h>
-#include <pthread.h>
-#include <sched.h>
-
-#include "liburing.h"
-#include "barrier.h"
-
-#define min(a, b)		((a < b) ? (a) : (b))
-
-struct io_sq_ring {
-	unsigned *head;
-	unsigned *tail;
-	unsigned *ring_mask;
-	unsigned *ring_entries;
-	unsigned *flags;
-	unsigned *array;
-};
-
-struct io_cq_ring {
-	unsigned *head;
-	unsigned *tail;
-	unsigned *ring_mask;
-	unsigned *ring_entries;
-	struct io_uring_cqe *cqes;
-};
-
-#define DEPTH			128
-
-#define BATCH_SUBMIT		32
-#define BATCH_COMPLETE		32
-
-#define BS			4096
-
-#define MAX_FDS			16
-
-static unsigned sq_ring_mask, cq_ring_mask;
-
-struct file {
-	unsigned long max_blocks;
-	unsigned pending_ios;
-	int real_fd;
-	int fixed_fd;
-};
-
-struct submitter {
-	pthread_t thread;
-	int ring_fd;
-	struct drand48_data rand;
-	struct io_sq_ring sq_ring;
-	struct io_uring_sqe *sqes;
-	struct iovec iovecs[DEPTH];
-	struct io_cq_ring cq_ring;
-	int inflight;
-	unsigned long reaps;
-	unsigned long done;
-	unsigned long calls;
-	volatile int finish;
-
-	__s32 *fds;
-
-	struct file files[MAX_FDS];
-	unsigned nr_files;
-	unsigned cur_file;
-};
-
-static struct submitter submitters[1];
-static volatile int finish;
-
-/*
- * OPTIONS: Set these to test the various features of io_uring.
- */
-static int polled = 1;		/* use IO polling */
-static int fixedbufs = 1;	/* use fixed user buffers */
-static int register_files = 1;	/* use fixed files */
-static int buffered = 0;	/* use buffered IO, not O_DIRECT */
-static int sq_thread_poll = 0;	/* use kernel submission/poller thread */
-static int sq_thread_cpu = -1;	/* pin above thread to this CPU */
-static int do_nop = 0;		/* no-op SQ ring commands */
-
-static int io_uring_register_buffers(struct submitter *s)
-{
-	if (do_nop)
-		return 0;
-
-	return io_uring_register(s->ring_fd, IORING_REGISTER_BUFFERS, s->iovecs,
-					DEPTH);
-}
-
-static int io_uring_register_files(struct submitter *s)
-{
-	unsigned i;
-
-	if (do_nop)
-		return 0;
-
-	s->fds = calloc(s->nr_files, sizeof(__s32));
-	for (i = 0; i < s->nr_files; i++) {
-		s->fds[i] = s->files[i].real_fd;
-		s->files[i].fixed_fd = i;
-	}
-
-	return io_uring_register(s->ring_fd, IORING_REGISTER_FILES, s->fds,
-					s->nr_files);
-}
-
-static int lk_gettid(void)
-{
-	return syscall(__NR_gettid);
-}
-
-static unsigned file_depth(struct submitter *s)
-{
-	return (DEPTH + s->nr_files - 1) / s->nr_files;
-}
-
-static void init_io(struct submitter *s, unsigned index)
-{
-	struct io_uring_sqe *sqe = &s->sqes[index];
-	unsigned long offset;
-	struct file *f;
-	long r;
-
-	if (do_nop) {
-		sqe->opcode = IORING_OP_NOP;
-		return;
-	}
-
-	if (s->nr_files == 1) {
-		f = &s->files[0];
-	} else {
-		f = &s->files[s->cur_file];
-		if (f->pending_ios >= file_depth(s)) {
-			s->cur_file++;
-			if (s->cur_file == s->nr_files)
-				s->cur_file = 0;
-			f = &s->files[s->cur_file];
-		}
-	}
-	f->pending_ios++;
-
-	lrand48_r(&s->rand, &r);
-	offset = (r % (f->max_blocks - 1)) * BS;
-
-	if (register_files) {
-		sqe->flags = IOSQE_FIXED_FILE;
-		sqe->fd = f->fixed_fd;
-	} else {
-		sqe->flags = 0;
-		sqe->fd = f->real_fd;
-	}
-	if (fixedbufs) {
-		sqe->opcode = IORING_OP_READ_FIXED;
-		sqe->addr = (unsigned long) s->iovecs[index].iov_base;
-		sqe->len = BS;
-		sqe->buf_index = index;
-	} else {
-		sqe->opcode = IORING_OP_READV;
-		sqe->addr = (unsigned long) &s->iovecs[index];
-		sqe->len = 1;
-		sqe->buf_index = 0;
-	}
-	sqe->ioprio = 0;
-	sqe->off = offset;
-	sqe->user_data = (unsigned long) f;
-}
-
-static int prep_more_ios(struct submitter *s, unsigned max_ios)
-{
-	struct io_sq_ring *ring = &s->sq_ring;
-	unsigned index, tail, next_tail, prepped = 0;
-
-	next_tail = tail = *ring->tail;
-	do {
-		next_tail++;
-		read_barrier();
-		if (next_tail == *ring->head)
-			break;
-
-		index = tail & sq_ring_mask;
-		init_io(s, index);
-		ring->array[index] = index;
-		prepped++;
-		tail = next_tail;
-	} while (prepped < max_ios);
-
-	if (*ring->tail != tail) {
-		/* order tail store with writes to sqes above */
-		write_barrier();
-		*ring->tail = tail;
-		write_barrier();
-	}
-	return prepped;
-}
-
-static int get_file_size(struct file *f)
-{
-	struct stat st;
-
-	if (fstat(f->real_fd, &st) < 0)
-		return -1;
-	if (S_ISBLK(st.st_mode)) {
-		unsigned long long bytes;
-
-		if (ioctl(f->real_fd, BLKGETSIZE64, &bytes) != 0)
-			return -1;
-
-		f->max_blocks = bytes / BS;
-		return 0;
-	} else if (S_ISREG(st.st_mode)) {
-		f->max_blocks = st.st_size / BS;
-		return 0;
-	}
-
-	return -1;
-}
-
-static int reap_events(struct submitter *s)
-{
-	struct io_cq_ring *ring = &s->cq_ring;
-	struct io_uring_cqe *cqe;
-	unsigned head, reaped = 0;
-
-	head = *ring->head;
-	do {
-		struct file *f;
-
-		read_barrier();
-		if (head == *ring->tail)
-			break;
-		cqe = &ring->cqes[head & cq_ring_mask];
-		if (!do_nop) {
-			f = (struct file *) (uintptr_t) cqe->user_data;
-			f->pending_ios--;
-			if (cqe->res != BS) {
-				printf("io: unexpected ret=%d\n", cqe->res);
-				if (polled && cqe->res == -EOPNOTSUPP)
-					printf("Your filesystem doesn't support poll\n");
-				return -1;
-			}
-		}
-		reaped++;
-		head++;
-	} while (1);
-
-	s->inflight -= reaped;
-	*ring->head = head;
-	write_barrier();
-	return reaped;
-}
-
-static void *submitter_fn(void *data)
-{
-	struct submitter *s = data;
-	struct io_sq_ring *ring = &s->sq_ring;
-	int ret, prepped;
-
-	printf("submitter=%d\n", lk_gettid());
-
-	srand48_r(pthread_self(), &s->rand);
-
-	prepped = 0;
-	do {
-		int to_wait, to_submit, this_reap, to_prep;
-
-		if (!prepped && s->inflight < DEPTH) {
-			to_prep = min(DEPTH - s->inflight, BATCH_SUBMIT);
-			prepped = prep_more_ios(s, to_prep);
-		}
-		s->inflight += prepped;
-submit_more:
-		to_submit = prepped;
-submit:
-		if (to_submit && (s->inflight + to_submit <= DEPTH))
-			to_wait = 0;
-		else
-			to_wait = min(s->inflight + to_submit, BATCH_COMPLETE);
-
-		/*
-		 * Only need to call io_uring_enter if we're not using SQ thread
-		 * poll, or if IORING_SQ_NEED_WAKEUP is set.
-		 */
-		if (!sq_thread_poll || (*ring->flags & IORING_SQ_NEED_WAKEUP)) {
-			unsigned flags = 0;
-
-			if (to_wait)
-				flags = IORING_ENTER_GETEVENTS;
-			if ((*ring->flags & IORING_SQ_NEED_WAKEUP))
-				flags |= IORING_ENTER_SQ_WAKEUP;
-			ret = io_uring_enter(s->ring_fd, to_submit, to_wait,
-						flags, NULL);
-			s->calls++;
-		}
-
-		/*
-		 * For non SQ thread poll, we already got the events we needed
-		 * through the io_uring_enter() above. For SQ thread poll, we
-		 * need to loop here until we find enough events.
-		 */
-		this_reap = 0;
-		do {
-			int r;
-			r = reap_events(s);
-			if (r == -1) {
-				s->finish = 1;
-				break;
-			} else if (r > 0)
-				this_reap += r;
-		} while (sq_thread_poll && this_reap < to_wait);
-		s->reaps += this_reap;
-
-		if (ret >= 0) {
-			if (!ret) {
-				to_submit = 0;
-				if (s->inflight)
-					goto submit;
-				continue;
-			} else if (ret < to_submit) {
-				int diff = to_submit - ret;
-
-				s->done += ret;
-				prepped -= diff;
-				goto submit_more;
-			}
-			s->done += ret;
-			prepped = 0;
-			continue;
-		} else if (ret < 0) {
-			if (errno == EAGAIN) {
-				if (s->finish)
-					break;
-				if (this_reap)
-					goto submit;
-				to_submit = 0;
-				goto submit;
-			}
-			printf("io_submit: %s\n", strerror(errno));
-			break;
-		}
-	} while (!s->finish);
-
-	finish = 1;
-	return NULL;
-}
-
-static void sig_int(int sig)
-{
-	printf("Exiting on signal %d\n", sig);
-	submitters[0].finish = 1;
-	finish = 1;
-}
-
-static void arm_sig_int(void)
-{
-	struct sigaction act;
-
-	memset(&act, 0, sizeof(act));
-	act.sa_handler = sig_int;
-	act.sa_flags = SA_RESTART;
-	sigaction(SIGINT, &act, NULL);
-}
-
-static int setup_ring(struct submitter *s)
-{
-	struct io_sq_ring *sring = &s->sq_ring;
-	struct io_cq_ring *cring = &s->cq_ring;
-	struct io_uring_params p;
-	int ret, fd;
-	void *ptr;
-
-	memset(&p, 0, sizeof(p));
-
-	if (polled && !do_nop)
-		p.flags |= IORING_SETUP_IOPOLL;
-	if (sq_thread_poll) {
-		p.flags |= IORING_SETUP_SQPOLL;
-		if (sq_thread_cpu != -1) {
-			p.flags |= IORING_SETUP_SQ_AFF;
-			p.sq_thread_cpu = sq_thread_cpu;
-		}
-	}
-
-	fd = io_uring_setup(DEPTH, &p);
-	if (fd < 0) {
-		perror("io_uring_setup");
-		return 1;
-	}
-	s->ring_fd = fd;
-
-	if (fixedbufs) {
-		ret = io_uring_register_buffers(s);
-		if (ret < 0) {
-			perror("io_uring_register_buffers");
-			return 1;
-		}
-	}
-
-	if (register_files) {
-		ret = io_uring_register_files(s);
-		if (ret < 0) {
-			perror("io_uring_register_files");
-			return 1;
-		}
-	}
-
-	ptr = mmap(0, p.sq_off.array + p.sq_entries * sizeof(__u32),
-			PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
-			IORING_OFF_SQ_RING);
-	printf("sq_ring ptr = 0x%p\n", ptr);
-	sring->head = ptr + p.sq_off.head;
-	sring->tail = ptr + p.sq_off.tail;
-	sring->ring_mask = ptr + p.sq_off.ring_mask;
-	sring->ring_entries = ptr + p.sq_off.ring_entries;
-	sring->flags = ptr + p.sq_off.flags;
-	sring->array = ptr + p.sq_off.array;
-	sq_ring_mask = *sring->ring_mask;
-
-	s->sqes = mmap(0, p.sq_entries * sizeof(struct io_uring_sqe),
-			PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
-			IORING_OFF_SQES);
-	printf("sqes ptr    = 0x%p\n", s->sqes);
-
-	ptr = mmap(0, p.cq_off.cqes + p.cq_entries * sizeof(struct io_uring_cqe),
-			PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
-			IORING_OFF_CQ_RING);
-	printf("cq_ring ptr = 0x%p\n", ptr);
-	cring->head = ptr + p.cq_off.head;
-	cring->tail = ptr + p.cq_off.tail;
-	cring->ring_mask = ptr + p.cq_off.ring_mask;
-	cring->ring_entries = ptr + p.cq_off.ring_entries;
-	cring->cqes = ptr + p.cq_off.cqes;
-	cq_ring_mask = *cring->ring_mask;
-	return 0;
-}
-
-static void file_depths(char *buf)
-{
-	struct submitter *s = &submitters[0];
-	unsigned i;
-	char *p;
-
-	buf[0] = '\0';
-	p = buf;
-	for (i = 0; i < s->nr_files; i++) {
-		struct file *f = &s->files[i];
-
-		if (i + 1 == s->nr_files)
-			p += sprintf(p, "%d", f->pending_ios);
-		else
-			p += sprintf(p, "%d, ", f->pending_ios);
-	}
-}
-
-int main(int argc, char *argv[])
-{
-	struct submitter *s = &submitters[0];
-	unsigned long done, calls, reap;
-	int err, i, flags, fd;
-	char *fdepths;
-	void *ret;
-
-	if (!do_nop && argc < 2) {
-		printf("%s: filename\n", argv[0]);
-		return 1;
-	}
-
-	flags = O_RDONLY | O_NOATIME;
-	if (!buffered)
-		flags |= O_DIRECT;
-
-	i = 1;
-	while (!do_nop && i < argc) {
-		struct file *f;
-
-		if (s->nr_files == MAX_FDS) {
-			printf("Max number of files (%d) reached\n", MAX_FDS);
-			break;
-		}
-		fd = open(argv[i], flags);
-		if (fd < 0) {
-			perror("open");
-			return 1;
-		}
-
-		f = &s->files[s->nr_files];
-		f->real_fd = fd;
-		if (get_file_size(f)) {
-			printf("failed getting size of device/file\n");
-			return 1;
-		}
-		if (f->max_blocks <= 1) {
-			printf("Zero file/device size?\n");
-			return 1;
-		}
-		f->max_blocks--;
-
-		printf("Added file %s\n", argv[i]);
-		s->nr_files++;
-		i++;
-	}
-
-	if (fixedbufs) {
-		struct rlimit rlim;
-
-		rlim.rlim_cur = RLIM_INFINITY;
-		rlim.rlim_max = RLIM_INFINITY;
-		if (setrlimit(RLIMIT_MEMLOCK, &rlim) < 0) {
-			perror("setrlimit");
-			return 1;
-		}
-	}
-
-	arm_sig_int();
-
-	for (i = 0; i < DEPTH; i++) {
-		void *buf;
-
-		if (posix_memalign(&buf, BS, BS)) {
-			printf("failed alloc\n");
-			return 1;
-		}
-		s->iovecs[i].iov_base = buf;
-		s->iovecs[i].iov_len = BS;
-	}
-
-	err = setup_ring(s);
-	if (err) {
-		printf("ring setup failed: %s, %d\n", strerror(errno), err);
-		return 1;
-	}
-	printf("polled=%d, fixedbufs=%d, buffered=%d", polled, fixedbufs, buffered);
-	printf(" QD=%d, sq_ring=%d, cq_ring=%d\n", DEPTH, *s->sq_ring.ring_entries, *s->cq_ring.ring_entries);
-
-	pthread_create(&s->thread, NULL, submitter_fn, s);
-
-	fdepths = malloc(8 * s->nr_files);
-	reap = calls = done = 0;
-	do {
-		unsigned long this_done = 0;
-		unsigned long this_reap = 0;
-		unsigned long this_call = 0;
-		unsigned long rpc = 0, ipc = 0;
-
-		sleep(1);
-		this_done += s->done;
-		this_call += s->calls;
-		this_reap += s->reaps;
-		if (this_call - calls) {
-			rpc = (this_done - done) / (this_call - calls);
-			ipc = (this_reap - reap) / (this_call - calls);
-		} else
-			rpc = ipc = -1;
-		file_depths(fdepths);
-		printf("IOPS=%lu, IOS/call=%ld/%ld, inflight=%u (%s)\n",
-				this_done - done, rpc, ipc, s->inflight,
-				fdepths);
-		done = this_done;
-		calls = this_call;
-		reap = this_reap;
-	} while (!finish);
-
-	pthread_join(s->thread, &ret);
-	close(s->ring_fd);
-	free(fdepths);
-	return 0;
-}
diff --git a/tools/io_uring/io_uring-cp.c b/tools/io_uring/io_uring-cp.c
deleted file mode 100644
index d9bd6f5f8f46..000000000000
--- a/tools/io_uring/io_uring-cp.c
+++ /dev/null
@@ -1,283 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Simple test program that demonstrates a file copy through io_uring. This
- * uses the API exposed by liburing.
- *
- * Copyright (C) 2018-2019 Jens Axboe
- */
-#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 "liburing.h"
-
-#define QD	64
-#define BS	(32*1024)
-
-static int infd, outfd;
-
-struct io_data {
-	int read;
-	off_t first_offset, offset;
-	size_t first_len;
-	struct iovec iov;
-};
-
-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 void queue_prepped(struct io_uring *ring, struct io_data *data)
-{
-	struct io_uring_sqe *sqe;
-
-	sqe = io_uring_get_sqe(ring);
-	assert(sqe);
-
-	if (data->read)
-		io_uring_prep_readv(sqe, infd, &data->iov, 1, data->offset);
-	else
-		io_uring_prep_writev(sqe, outfd, &data->iov, 1, data->offset);
-
-	io_uring_sqe_set_data(sqe, data);
-}
-
-static int queue_read(struct io_uring *ring, off_t size, off_t offset)
-{
-	struct io_uring_sqe *sqe;
-	struct io_data *data;
-
-	data = malloc(size + sizeof(*data));
-	if (!data)
-		return 1;
-
-	sqe = io_uring_get_sqe(ring);
-	if (!sqe) {
-		free(data);
-		return 1;
-	}
-
-	data->read = 1;
-	data->offset = data->first_offset = offset;
-
-	data->iov.iov_base = data + 1;
-	data->iov.iov_len = size;
-	data->first_len = size;
-
-	io_uring_prep_readv(sqe, infd, &data->iov, 1, offset);
-	io_uring_sqe_set_data(sqe, data);
-	return 0;
-}
-
-static void queue_write(struct io_uring *ring, struct io_data *data)
-{
-	data->read = 0;
-	data->offset = data->first_offset;
-
-	data->iov.iov_base = data + 1;
-	data->iov.iov_len = data->first_len;
-
-	queue_prepped(ring, data);
-	io_uring_submit(ring);
-}
-
-static int copy_file(struct io_uring *ring, off_t insize)
-{
-	unsigned long reads, writes;
-	struct io_uring_cqe *cqe;
-	off_t write_left, offset;
-	int ret;
-
-	write_left = insize;
-	writes = reads = offset = 0;
-
-	while (insize || write_left) {
-		int had_reads, got_comp;
-
-		/*
-		 * Queue up as many reads as we can
-		 */
-		had_reads = reads;
-		while (insize) {
-			off_t this_size = insize;
-
-			if (reads + writes >= QD)
-				break;
-			if (this_size > BS)
-				this_size = BS;
-			else if (!this_size)
-				break;
-
-			if (queue_read(ring, this_size, offset))
-				break;
-
-			insize -= this_size;
-			offset += this_size;
-			reads++;
-		}
-
-		if (had_reads != reads) {
-			ret = io_uring_submit(ring);
-			if (ret < 0) {
-				fprintf(stderr, "io_uring_submit: %s\n", strerror(-ret));
-				break;
-			}
-		}
-
-		/*
-		 * Queue is full at this point. Find at least one completion.
-		 */
-		got_comp = 0;
-		while (write_left) {
-			struct io_data *data;
-
-			if (!got_comp) {
-				ret = io_uring_wait_cqe(ring, &cqe);
-				got_comp = 1;
-			} else {
-				ret = io_uring_peek_cqe(ring, &cqe);
-				if (ret == -EAGAIN) {
-					cqe = NULL;
-					ret = 0;
-				}
-			}
-			if (ret < 0) {
-				fprintf(stderr, "io_uring_peek_cqe: %s\n",
-							strerror(-ret));
-				return 1;
-			}
-			if (!cqe)
-				break;
-
-			data = io_uring_cqe_get_data(cqe);
-			if (cqe->res < 0) {
-				if (cqe->res == -EAGAIN) {
-					queue_prepped(ring, data);
-					io_uring_cqe_seen(ring, cqe);
-					continue;
-				}
-				fprintf(stderr, "cqe failed: %s\n",
-						strerror(-cqe->res));
-				return 1;
-			} else if (cqe->res != data->iov.iov_len) {
-				/* Short read/write, adjust and requeue */
-				data->iov.iov_base += cqe->res;
-				data->iov.iov_len -= cqe->res;
-				data->offset += cqe->res;
-				queue_prepped(ring, data);
-				io_uring_cqe_seen(ring, cqe);
-				continue;
-			}
-
-			/*
-			 * All done. if write, nothing else to do. if read,
-			 * queue up corresponding write.
-			 */
-			if (data->read) {
-				queue_write(ring, data);
-				write_left -= data->first_len;
-				reads--;
-				writes++;
-			} else {
-				free(data);
-				writes--;
-			}
-			io_uring_cqe_seen(ring, cqe);
-		}
-	}
-
-	/* wait out pending writes */
-	while (writes) {
-		struct io_data *data;
-
-		ret = io_uring_wait_cqe(ring, &cqe);
-		if (ret) {
-			fprintf(stderr, "wait_cqe=%d\n", ret);
-			return 1;
-		}
-		if (cqe->res < 0) {
-			fprintf(stderr, "write res=%d\n", cqe->res);
-			return 1;
-		}
-		data = io_uring_cqe_get_data(cqe);
-		free(data);
-		writes--;
-		io_uring_cqe_seen(ring, cqe);
-	}
-
-	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;
-}
diff --git a/tools/io_uring/liburing.h b/tools/io_uring/liburing.h
deleted file mode 100644
index 28a837b6069d..000000000000
--- a/tools/io_uring/liburing.h
+++ /dev/null
@@ -1,187 +0,0 @@
-#ifndef LIB_URING_H
-#define LIB_URING_H
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#include <sys/uio.h>
-#include <signal.h>
-#include <string.h>
-#include "../../include/uapi/linux/io_uring.h"
-#include <inttypes.h>
-#include <linux/swab.h>
-#include "barrier.h"
-
-/*
- * Library interface to io_uring
- */
-struct io_uring_sq {
-	unsigned *khead;
-	unsigned *ktail;
-	unsigned *kring_mask;
-	unsigned *kring_entries;
-	unsigned *kflags;
-	unsigned *kdropped;
-	unsigned *array;
-	struct io_uring_sqe *sqes;
-
-	unsigned sqe_head;
-	unsigned sqe_tail;
-
-	size_t ring_sz;
-};
-
-struct io_uring_cq {
-	unsigned *khead;
-	unsigned *ktail;
-	unsigned *kring_mask;
-	unsigned *kring_entries;
-	unsigned *koverflow;
-	struct io_uring_cqe *cqes;
-
-	size_t ring_sz;
-};
-
-struct io_uring {
-	struct io_uring_sq sq;
-	struct io_uring_cq cq;
-	int ring_fd;
-};
-
-/*
- * System calls
- */
-extern int io_uring_setup(unsigned entries, struct io_uring_params *p);
-extern int io_uring_enter(int fd, unsigned to_submit,
-	unsigned min_complete, unsigned flags, sigset_t *sig);
-extern int io_uring_register(int fd, unsigned int opcode, void *arg,
-	unsigned int nr_args);
-
-/*
- * Library interface
- */
-extern int io_uring_queue_init(unsigned entries, struct io_uring *ring,
-	unsigned flags);
-extern int io_uring_queue_mmap(int fd, struct io_uring_params *p,
-	struct io_uring *ring);
-extern void io_uring_queue_exit(struct io_uring *ring);
-extern int io_uring_peek_cqe(struct io_uring *ring,
-	struct io_uring_cqe **cqe_ptr);
-extern int io_uring_wait_cqe(struct io_uring *ring,
-	struct io_uring_cqe **cqe_ptr);
-extern int io_uring_submit(struct io_uring *ring);
-extern struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring);
-
-/*
- * Must be called after io_uring_{peek,wait}_cqe() after the cqe has
- * been processed by the application.
- */
-static inline void io_uring_cqe_seen(struct io_uring *ring,
-				     struct io_uring_cqe *cqe)
-{
-	if (cqe) {
-		struct io_uring_cq *cq = &ring->cq;
-
-		(*cq->khead)++;
-		/*
-		 * Ensure that the kernel sees our new head, the kernel has
-		 * the matching read barrier.
-		 */
-		write_barrier();
-	}
-}
-
-/*
- * Command prep helpers
- */
-static inline void io_uring_sqe_set_data(struct io_uring_sqe *sqe, void *data)
-{
-	sqe->user_data = (unsigned long) data;
-}
-
-static inline void *io_uring_cqe_get_data(struct io_uring_cqe *cqe)
-{
-	return (void *) (uintptr_t) cqe->user_data;
-}
-
-static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
-				    const void *addr, unsigned len,
-				    off_t offset)
-{
-	memset(sqe, 0, sizeof(*sqe));
-	sqe->opcode = op;
-	sqe->fd = fd;
-	sqe->off = offset;
-	sqe->addr = (unsigned long) addr;
-	sqe->len = len;
-}
-
-static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
-				       const struct iovec *iovecs,
-				       unsigned nr_vecs, off_t offset)
-{
-	io_uring_prep_rw(IORING_OP_READV, sqe, fd, iovecs, nr_vecs, offset);
-}
-
-static inline void io_uring_prep_read_fixed(struct io_uring_sqe *sqe, int fd,
-					    void *buf, unsigned nbytes,
-					    off_t offset)
-{
-	io_uring_prep_rw(IORING_OP_READ_FIXED, sqe, fd, buf, nbytes, offset);
-}
-
-static inline void io_uring_prep_writev(struct io_uring_sqe *sqe, int fd,
-					const struct iovec *iovecs,
-					unsigned nr_vecs, off_t offset)
-{
-	io_uring_prep_rw(IORING_OP_WRITEV, sqe, fd, iovecs, nr_vecs, offset);
-}
-
-static inline void io_uring_prep_write_fixed(struct io_uring_sqe *sqe, int fd,
-					     const void *buf, unsigned nbytes,
-					     off_t offset)
-{
-	io_uring_prep_rw(IORING_OP_WRITE_FIXED, sqe, fd, buf, nbytes, offset);
-}
-
-static inline void io_uring_prep_poll_add(struct io_uring_sqe *sqe, int fd,
-					  unsigned poll_mask)
-{
-	memset(sqe, 0, sizeof(*sqe));
-	sqe->opcode = IORING_OP_POLL_ADD;
-	sqe->fd = fd;
-#if __BYTE_ORDER == __BIG_ENDIAN
-	poll_mask = __swahw32(poll_mask);
-#endif
-	sqe->poll_events = poll_mask;
-}
-
-static inline void io_uring_prep_poll_remove(struct io_uring_sqe *sqe,
-					     void *user_data)
-{
-	memset(sqe, 0, sizeof(*sqe));
-	sqe->opcode = IORING_OP_POLL_REMOVE;
-	sqe->addr = (unsigned long) user_data;
-}
-
-static inline void io_uring_prep_fsync(struct io_uring_sqe *sqe, int fd,
-				       unsigned fsync_flags)
-{
-	memset(sqe, 0, sizeof(*sqe));
-	sqe->opcode = IORING_OP_FSYNC;
-	sqe->fd = fd;
-	sqe->fsync_flags = fsync_flags;
-}
-
-static inline void io_uring_prep_nop(struct io_uring_sqe *sqe)
-{
-	memset(sqe, 0, sizeof(*sqe));
-	sqe->opcode = IORING_OP_NOP;
-}
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif
diff --git a/tools/io_uring/queue.c b/tools/io_uring/queue.c
deleted file mode 100644
index 321819c132c7..000000000000
--- a/tools/io_uring/queue.c
+++ /dev/null
@@ -1,156 +0,0 @@
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-
-#include "liburing.h"
-#include "barrier.h"
-
-static int __io_uring_get_cqe(struct io_uring *ring,
-			      struct io_uring_cqe **cqe_ptr, int wait)
-{
-	struct io_uring_cq *cq = &ring->cq;
-	const unsigned mask = *cq->kring_mask;
-	unsigned head;
-	int ret;
-
-	*cqe_ptr = NULL;
-	head = *cq->khead;
-	do {
-		/*
-		 * It's necessary to use a read_barrier() before reading
-		 * the CQ tail, since the kernel updates it locklessly. The
-		 * kernel has the matching store barrier for the update. The
-		 * kernel also ensures that previous stores to CQEs are ordered
-		 * with the tail update.
-		 */
-		read_barrier();
-		if (head != *cq->ktail) {
-			*cqe_ptr = &cq->cqes[head & mask];
-			break;
-		}
-		if (!wait)
-			break;
-		ret = io_uring_enter(ring->ring_fd, 0, 1,
-					IORING_ENTER_GETEVENTS, NULL);
-		if (ret < 0)
-			return -errno;
-	} while (1);
-
-	return 0;
-}
-
-/*
- * Return an IO completion, if one is readily available. Returns 0 with
- * cqe_ptr filled in on success, -errno on failure.
- */
-int io_uring_peek_cqe(struct io_uring *ring, struct io_uring_cqe **cqe_ptr)
-{
-	return __io_uring_get_cqe(ring, cqe_ptr, 0);
-}
-
-/*
- * Return an IO completion, waiting for it if necessary. Returns 0 with
- * cqe_ptr filled in on success, -errno on failure.
- */
-int io_uring_wait_cqe(struct io_uring *ring, struct io_uring_cqe **cqe_ptr)
-{
-	return __io_uring_get_cqe(ring, cqe_ptr, 1);
-}
-
-/*
- * Submit sqes acquired from io_uring_get_sqe() to the kernel.
- *
- * Returns number of sqes submitted
- */
-int io_uring_submit(struct io_uring *ring)
-{
-	struct io_uring_sq *sq = &ring->sq;
-	const unsigned mask = *sq->kring_mask;
-	unsigned ktail, ktail_next, submitted, to_submit;
-	int ret;
-
-	/*
-	 * If we have pending IO in the kring, submit it first. We need a
-	 * read barrier here to match the kernels store barrier when updating
-	 * the SQ head.
-	 */
-	read_barrier();
-	if (*sq->khead != *sq->ktail) {
-		submitted = *sq->kring_entries;
-		goto submit;
-	}
-
-	if (sq->sqe_head == sq->sqe_tail)
-		return 0;
-
-	/*
-	 * Fill in sqes that we have queued up, adding them to the kernel ring
-	 */
-	submitted = 0;
-	ktail = ktail_next = *sq->ktail;
-	to_submit = sq->sqe_tail - sq->sqe_head;
-	while (to_submit--) {
-		ktail_next++;
-		read_barrier();
-
-		sq->array[ktail & mask] = sq->sqe_head & mask;
-		ktail = ktail_next;
-
-		sq->sqe_head++;
-		submitted++;
-	}
-
-	if (!submitted)
-		return 0;
-
-	if (*sq->ktail != ktail) {
-		/*
-		 * First write barrier ensures that the SQE stores are updated
-		 * with the tail update. This is needed so that the kernel
-		 * will never see a tail update without the preceeding sQE
-		 * stores being done.
-		 */
-		write_barrier();
-		*sq->ktail = ktail;
-		/*
-		 * The kernel has the matching read barrier for reading the
-		 * SQ tail.
-		 */
-		write_barrier();
-	}
-
-submit:
-	ret = io_uring_enter(ring->ring_fd, submitted, 0,
-				IORING_ENTER_GETEVENTS, NULL);
-	if (ret < 0)
-		return -errno;
-
-	return ret;
-}
-
-/*
- * Return an sqe to fill. Application must later call io_uring_submit()
- * when it's ready to tell the kernel about it. The caller may call this
- * function multiple times before calling io_uring_submit().
- *
- * Returns a vacant sqe, or NULL if we're full.
- */
-struct io_uring_sqe *io_uring_get_sqe(struct io_uring *ring)
-{
-	struct io_uring_sq *sq = &ring->sq;
-	unsigned next = sq->sqe_tail + 1;
-	struct io_uring_sqe *sqe;
-
-	/*
-	 * All sqes are used
-	 */
-	if (next - sq->sqe_head > *sq->kring_entries)
-		return NULL;
-
-	sqe = &sq->sqes[sq->sqe_tail & *sq->kring_mask];
-	sq->sqe_tail = next;
-	return sqe;
-}
diff --git a/tools/io_uring/setup.c b/tools/io_uring/setup.c
deleted file mode 100644
index 0b50fcd78520..000000000000
--- a/tools/io_uring/setup.c
+++ /dev/null
@@ -1,107 +0,0 @@
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/mman.h>
-#include <unistd.h>
-#include <errno.h>
-#include <string.h>
-
-#include "liburing.h"
-
-static int io_uring_mmap(int fd, struct io_uring_params *p,
-			 struct io_uring_sq *sq, struct io_uring_cq *cq)
-{
-	size_t size;
-	void *ptr;
-	int ret;
-
-	sq->ring_sz = p->sq_off.array + p->sq_entries * sizeof(unsigned);
-	ptr = mmap(0, sq->ring_sz, PROT_READ | PROT_WRITE,
-			MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_SQ_RING);
-	if (ptr == MAP_FAILED)
-		return -errno;
-	sq->khead = ptr + p->sq_off.head;
-	sq->ktail = ptr + p->sq_off.tail;
-	sq->kring_mask = ptr + p->sq_off.ring_mask;
-	sq->kring_entries = ptr + p->sq_off.ring_entries;
-	sq->kflags = ptr + p->sq_off.flags;
-	sq->kdropped = ptr + p->sq_off.dropped;
-	sq->array = ptr + p->sq_off.array;
-
-	size = p->sq_entries * sizeof(struct io_uring_sqe);
-	sq->sqes = mmap(0, size, PROT_READ | PROT_WRITE,
-				MAP_SHARED | MAP_POPULATE, fd,
-				IORING_OFF_SQES);
-	if (sq->sqes == MAP_FAILED) {
-		ret = -errno;
-err:
-		munmap(sq->khead, sq->ring_sz);
-		return ret;
-	}
-
-	cq->ring_sz = p->cq_off.cqes + p->cq_entries * sizeof(struct io_uring_cqe);
-	ptr = mmap(0, cq->ring_sz, PROT_READ | PROT_WRITE,
-			MAP_SHARED | MAP_POPULATE, fd, IORING_OFF_CQ_RING);
-	if (ptr == MAP_FAILED) {
-		ret = -errno;
-		munmap(sq->sqes, p->sq_entries * sizeof(struct io_uring_sqe));
-		goto err;
-	}
-	cq->khead = ptr + p->cq_off.head;
-	cq->ktail = ptr + p->cq_off.tail;
-	cq->kring_mask = ptr + p->cq_off.ring_mask;
-	cq->kring_entries = ptr + p->cq_off.ring_entries;
-	cq->koverflow = ptr + p->cq_off.overflow;
-	cq->cqes = ptr + p->cq_off.cqes;
-	return 0;
-}
-
-/*
- * For users that want to specify sq_thread_cpu or sq_thread_idle, this
- * interface is a convenient helper for mmap()ing the rings.
- * Returns -1 on error, or zero on success.  On success, 'ring'
- * contains the necessary information to read/write to the rings.
- */
-int io_uring_queue_mmap(int fd, struct io_uring_params *p, struct io_uring *ring)
-{
-	int ret;
-
-	memset(ring, 0, sizeof(*ring));
-	ret = io_uring_mmap(fd, p, &ring->sq, &ring->cq);
-	if (!ret)
-		ring->ring_fd = fd;
-	return ret;
-}
-
-/*
- * Returns -1 on error, or zero on success. On success, 'ring'
- * contains the necessary information to read/write to the rings.
- */
-int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
-{
-	struct io_uring_params p;
-	int fd, ret;
-
-	memset(&p, 0, sizeof(p));
-	p.flags = flags;
-
-	fd = io_uring_setup(entries, &p);
-	if (fd < 0)
-		return fd;
-
-	ret = io_uring_queue_mmap(fd, &p, ring);
-	if (ret)
-		close(fd);
-
-	return ret;
-}
-
-void io_uring_queue_exit(struct io_uring *ring)
-{
-	struct io_uring_sq *sq = &ring->sq;
-	struct io_uring_cq *cq = &ring->cq;
-
-	munmap(sq->sqes, *sq->kring_entries * sizeof(struct io_uring_sqe));
-	munmap(sq->khead, sq->ring_sz);
-	munmap(cq->khead, cq->ring_sz);
-	close(ring->ring_fd);
-}
diff --git a/tools/io_uring/syscall.c b/tools/io_uring/syscall.c
deleted file mode 100644
index b22e0aa54e9d..000000000000
--- a/tools/io_uring/syscall.c
+++ /dev/null
@@ -1,52 +0,0 @@
-/*
- * Will go away once libc support is there
- */
-#include <unistd.h>
-#include <sys/syscall.h>
-#include <sys/uio.h>
-#include <signal.h>
-#include "liburing.h"
-
-#ifdef __alpha__
-/*
- * alpha is the only exception, all other architectures
- * have common numbers for new system calls.
- */
-# ifndef __NR_io_uring_setup
-#  define __NR_io_uring_setup		535
-# endif
-# ifndef __NR_io_uring_enter
-#  define __NR_io_uring_enter		536
-# endif
-# ifndef __NR_io_uring_register
-#  define __NR_io_uring_register	537
-# endif
-#else /* !__alpha__ */
-# ifndef __NR_io_uring_setup
-#  define __NR_io_uring_setup		425
-# endif
-# ifndef __NR_io_uring_enter
-#  define __NR_io_uring_enter		426
-# endif
-# ifndef __NR_io_uring_register
-#  define __NR_io_uring_register	427
-# endif
-#endif
-
-int io_uring_register(int fd, unsigned int opcode, void *arg,
-		      unsigned int nr_args)
-{
-	return syscall(__NR_io_uring_register, fd, opcode, arg, nr_args);
-}
-
-int io_uring_setup(unsigned int entries, struct io_uring_params *p)
-{
-	return syscall(__NR_io_uring_setup, entries, p);
-}
-
-int io_uring_enter(int fd, unsigned int to_submit, unsigned int min_complete,
-		   unsigned int flags, sigset_t *sig)
-{
-	return syscall(__NR_io_uring_enter, fd, to_submit, min_complete,
-			flags, sig, _NSIG / 8);
-}
-- 
2.41.0

Re: [PATCH 1/1] io_uring: kill io_uring userspace examples

[Jens Axboe]

On Wed, 09 Aug 2023 13:22:52 +0100, Pavel Begunkov wrote:
> There are tons of io_uring tests and examples in liburing and on the
> Internet. If you're looking for a benchmark, io_uring-bench.c is just an
> acutely outdated version of fio/io_uring. And for basic condensed init
> template for likes of selftests take a peek at io_uring_zerocopy_tx.c.
> 
> Kill tools/io_uring/, it's a burden keeping it here.
> 
> [...]

Applied, thanks!

[1/1] io_uring: kill io_uring userspace examples
      commit: f0939ef2dba5f42fadaebf8168691e95d3e4c7bc

Best regards,
-- 
Jens Axboe