tools/io_uring: sync with liburing

Various fixes and changes have been applied to liburing since we
copied some select bits to the kernel testing/examples part, sync
up with liburing to get those changes.

Most notable is the change that split the CQE reading into the peek
and seen event, instead of being just a single function. Also fixes
an unsigned wrap issue in io_uring_submit(), leak of 'fd' in setup
if we fail, and various other little issues.

Signed-off-by: Jens Axboe <[email protected]>

Author: axboe

tools/io_uring/io_uring-cp.c

@@ -13,6 +13,7 @@
 #include <assert.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <sys/types.h>
 #include <sys/stat.h>
 #include <sys/ioctl.h>
 
@@ -85,11 +86,16 @@ 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)
+	if (!sqe) {
+		free(data);
 		return 1;
+	}
 
-	data = malloc(size + sizeof(*data));
 	data->read = 1;
 	data->offset = data->first_offset = offset;
 
@@ -166,22 +172,23 @@ static int copy_file(struct io_uring *ring, off_t insize)
 			struct io_data *data;
 
 			if (!got_comp) {
-				ret = io_uring_wait_completion(ring, &cqe);
+				ret = io_uring_wait_cqe(ring, &cqe);
 				got_comp = 1;
 			} else
-				ret = io_uring_get_completion(ring, &cqe);
+				ret = io_uring_peek_cqe(ring, &cqe);
 			if (ret < 0) {
-				fprintf(stderr, "io_uring_get_completion: %s\n",
+				fprintf(stderr, "io_uring_peek_cqe: %s\n",
 							strerror(-ret));
 				return 1;
 			}
 			if (!cqe)
 				break;
 
-			data = (struct io_data *) (uintptr_t) cqe->user_data;
+			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",
@@ -193,6 +200,7 @@ static int copy_file(struct io_uring *ring, off_t insize)
 				data->iov.iov_len -= cqe->res;
 				data->offset += cqe->res;
 				queue_prepped(ring, data);
+				io_uring_cqe_seen(ring, cqe);
 				continue;
 			}
 
@@ -209,6 +217,7 @@ static int copy_file(struct io_uring *ring, off_t insize)
 				free(data);
 				writes--;
 			}
+			io_uring_cqe_seen(ring, cqe);
 		}
 	}
 

tools/io_uring/liburing.h

@@ -1,10 +1,16 @@
 #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 "barrier.h"
 
 /*
  * Library interface to io_uring
@@ -46,7 +52,7 @@ struct io_uring {
  * System calls
  */
 extern int io_uring_setup(unsigned entries, struct io_uring_params *p);
-extern int io_uring_enter(unsigned fd, unsigned to_submit,
+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);
@@ -59,13 +65,32 @@ extern int io_uring_queue_init(unsigned entries, struct io_uring *ring,
 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_get_completion(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_completion(struct io_uring *ring,
+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
  */
@@ -74,8 +99,14 @@ 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,
-				    void *addr, unsigned len, off_t offset)
+				    const void *addr, unsigned len,
+				    off_t offset)
 {
 	memset(sqe, 0, sizeof(*sqe));
 	sqe->opcode = op;
@@ -86,8 +117,8 @@ static inline void io_uring_prep_rw(int op, struct io_uring_sqe *sqe, int fd,
 }
 
 static inline void io_uring_prep_readv(struct io_uring_sqe *sqe, int fd,
-				       struct iovec *iovecs, unsigned nr_vecs,
-				       off_t offset)
+				       const struct iovec *iovecs,
+				       unsigned nr_vecs, off_t offset)
 {
 	io_uring_prep_rw(IORING_OP_READV, sqe, fd, iovecs, nr_vecs, offset);
 }
@@ -100,14 +131,14 @@ static inline void io_uring_prep_read_fixed(struct io_uring_sqe *sqe, int fd,
 }
 
 static inline void io_uring_prep_writev(struct io_uring_sqe *sqe, int fd,
-				        struct iovec *iovecs, unsigned nr_vecs,
-					off_t offset)
+					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,
-					     void *buf, unsigned nbytes,
+					     const void *buf, unsigned nbytes,
 					     off_t offset)
 {
 	io_uring_prep_rw(IORING_OP_WRITE_FIXED, sqe, fd, buf, nbytes, offset);
@@ -131,13 +162,22 @@ static inline void io_uring_prep_poll_remove(struct io_uring_sqe *sqe,
 }
 
 static inline void io_uring_prep_fsync(struct io_uring_sqe *sqe, int fd,
-				       int datasync)
+				       unsigned fsync_flags)
 {
 	memset(sqe, 0, sizeof(*sqe));
 	sqe->opcode = IORING_OP_FSYNC;
 	sqe->fd = fd;
-	if (datasync)
-		sqe->fsync_flags = IORING_FSYNC_DATASYNC;
+	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

tools/io_uring/queue.c

@@ -8,8 +8,8 @@
 #include "liburing.h"
 #include "barrier.h"
 
-static int __io_uring_get_completion(struct io_uring *ring,
-				     struct io_uring_cqe **cqe_ptr, int wait)
+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;
@@ -39,34 +39,25 @@ static int __io_uring_get_completion(struct io_uring *ring,
 			return -errno;
 	} while (1);
 
-	if (*cqe_ptr) {
-		*cq->khead = head + 1;
-		/*
-		 * Ensure that the kernel sees our new head, the kernel has
-		 * the matching read barrier.
-		 */
-		write_barrier();
-	}
-
 	return 0;
 }
 
 /*
- * Return an IO completion, if one is readily available
+ * Return an IO completion, if one is readily available. Returns 0 with
+ * cqe_ptr filled in on success, -errno on failure.
  */
-int io_uring_get_completion(struct io_uring *ring,
-			    struct io_uring_cqe **cqe_ptr)
+int io_uring_peek_cqe(struct io_uring *ring, struct io_uring_cqe **cqe_ptr)
 {
-	return __io_uring_get_completion(ring, cqe_ptr, 0);
+	return __io_uring_get_cqe(ring, cqe_ptr, 0);
 }
 
 /*
- * Return an IO completion, waiting for it if necessary
+ * 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_completion(struct io_uring *ring,
-			     struct io_uring_cqe **cqe_ptr)
+int io_uring_wait_cqe(struct io_uring *ring, struct io_uring_cqe **cqe_ptr)
 {
-	return __io_uring_get_completion(ring, cqe_ptr, 1);
+	return __io_uring_get_cqe(ring, cqe_ptr, 1);
 }
 
 /*
@@ -78,7 +69,7 @@ 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;
+	unsigned ktail, ktail_next, submitted, to_submit;
 	int ret;
 
 	/*
@@ -100,7 +91,8 @@ int io_uring_submit(struct io_uring *ring)
 	 */
 	submitted = 0;
 	ktail = ktail_next = *sq->ktail;
-	while (sq->sqe_head < sq->sqe_tail) {
+	to_submit = sq->sqe_tail - sq->sqe_head;
+	while (to_submit--) {
 		ktail_next++;
 		read_barrier();
 
@@ -136,7 +128,7 @@ int io_uring_submit(struct io_uring *ring)
 	if (ret < 0)
 		return -errno;
 
-	return 0;
+	return ret;
 }
 
 /*

tools/io_uring/setup.c

@@ -27,7 +27,7 @@ static int io_uring_mmap(int fd, struct io_uring_params *p,
 	sq->kdropped = ptr + p->sq_off.dropped;
 	sq->array = ptr + p->sq_off.array;
 
-	size = p->sq_entries * sizeof(struct io_uring_sqe),
+	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);
@@ -79,7 +79,7 @@ int io_uring_queue_mmap(int fd, struct io_uring_params *p, struct io_uring *ring
 int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
 {
 	struct io_uring_params p;
-	int fd;
+	int fd, ret;
 
 	memset(&p, 0, sizeof(p));
 	p.flags = flags;
@@ -88,7 +88,11 @@ int io_uring_queue_init(unsigned entries, struct io_uring *ring, unsigned flags)
 	if (fd < 0)
 		return fd;
 
-	return io_uring_queue_mmap(fd, &p, ring);
+	ret = io_uring_queue_mmap(fd, &p, ring);
+	if (ret)
+		close(fd);
+
+	return ret;
 }
 
 void io_uring_queue_exit(struct io_uring *ring)

tools/io_uring/syscall.c

@@ -7,34 +7,46 @@
 #include <signal.h>
 #include "liburing.h"
 
-#if defined(__x86_64) || defined(__i386__)
-#ifndef __NR_sys_io_uring_setup
-#define __NR_sys_io_uring_setup		425
-#endif
-#ifndef __NR_sys_io_uring_enter
-#define __NR_sys_io_uring_enter		426
-#endif
-#ifndef __NR_sys_io_uring_register
-#define __NR_sys_io_uring_register	427
-#endif
-#else
-#error "Arch not supported yet"
+#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_sys_io_uring_register, fd, opcode, arg, nr_args);
+	return syscall(__NR_io_uring_register, fd, opcode, arg, nr_args);
 }
 
-int io_uring_setup(unsigned entries, struct io_uring_params *p)
+int io_uring_setup(unsigned int entries, struct io_uring_params *p)
 {
-	return syscall(__NR_sys_io_uring_setup, entries, p);
+	return syscall(__NR_io_uring_setup, entries, p);
 }
 
-int io_uring_enter(unsigned fd, unsigned to_submit, unsigned min_complete,
-		   unsigned flags, sigset_t *sig)
+int io_uring_enter(int fd, unsigned int to_submit, unsigned int min_complete,
+		   unsigned int flags, sigset_t *sig)
 {
-	return syscall(__NR_sys_io_uring_enter, fd, to_submit, min_complete,
+	return syscall(__NR_io_uring_enter, fd, to_submit, min_complete,
 			flags, sig, _NSIG / 8);
 }