chore: adjust read-write, nvme example

examples/nvme/nvme.go

@@ -10,6 +10,12 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// NOTICE NOTICE NOTICE NOTICE NOTICE
+//
+//   This example is performing **READ** access to NVMe via low-level control device.
+//
+// NOTICE NOTICE NOTICE NOTICE NOTICE
+
 var (
 	// hardcoded device path
 	// devicePath = "/dev/nvme0n1"
@@ -78,10 +84,13 @@ func DoIoUring(devPath string) error {
 	}
 	defer unix.Close(fd)
 
-	var buf [0x1000]byte
+	var bufs [10][0x1000]byte
+	var sqe *uring.IoUringSqe
+	sqe = ring.GetSqe()
 
-	sqe := ring.GetSqe()
-	uring.PrepRead(sqe, fd, &buf[0], len(buf), 0)
+	buf := bufs[1]
+	bufSz := len(buf)
+	uring.PrepRead(sqe, fd, &buf[0], bufSz, 0)
 
 	sqe.SetCmdOp(uint32(nvme.NVME_URING_CMD_IO()))
 	sqe.Opcode = uring.IORING_OP_URING_CMD
@@ -104,8 +113,8 @@ func DoIoUring(devPath string) error {
 
 		Nsid: nsid,
 
-		Addr:    uint64(uintptr(unsafe.Pointer(&buf))),
-		DataLen: uint32(len(buf)),
+		Addr:    uint64(uintptr(unsafe.Pointer(&buf[0]))),
+		DataLen: uint32(bufSz),
 	}
 	cmdPtr := (*nvme.NvmeUringCmd)(sqe.GetCmd())
 	*cmdPtr = cmd // copy
@@ -119,15 +128,17 @@ func DoIoUring(devPath string) error {
 	fmt.Println("submitted", submitted)
 
 	var cqe *uring.IoUringCqe
+	// for i := 0; i < 2; i++ {
 	if err := ring.WaitCqe(&cqe); err != nil {
 		return err
 	}
-	ring.SeenCqe(cqe)
-
 	fmt.Printf("CQE:\t%+#v\n", cqe)
 	cqeExtra := (*[2]uint64)(cqe.GetBigCqe())
 	fmt.Printf("CQE Extra:\t%+#v\n", cqeExtra)
 	fmt.Printf("Buffer: %+#v\n", buf)
+	fmt.Printf("=========\n")
+	ring.SeenCqe(cqe)
+	// }
 	return nil
 }
 

examples/read-write/read_write.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"log"
+	"syscall"
+
+	uring "github.com/ii64/gouring"
+	"golang.org/x/sys/unix"
+)
+
+func main() {
+	ring, err := uring.New(256, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer ring.Close()
+
+	fd, err := unix.Open("/tmp/test", unix.O_RDWR|unix.O_CREAT, 0677)
+	if err != nil {
+		panic(err)
+	}
+
+	sqe := ring.GetSqe()
+	b := []byte("hello from io_uring!\n")
+	uring.PrepWrite(sqe, fd, &b[0], len(b), 0)
+	sqe.UserData.SetUint64(0x0001)
+	sqe.Flags |= uring.IOSQE_IO_LINK
+
+	sqe = ring.GetSqe()
+	uring.PrepWrite(sqe, syscall.Stdout, &b[0], len(b), 0)
+	sqe.UserData.SetUint64(0x0002)
+	sqe.Flags |= uring.IOSQE_IO_LINK
+
+	sqe = ring.GetSqe()
+	var buf = make([]byte, len(b))
+	uring.PrepRead(sqe, fd, &buf[0], len(buf), 0)
+	sqe.UserData.SetUint64(0x0003)
+	sqe.Flags |= uring.IOSQE_IO_LINK
+
+	sqe = ring.GetSqe()
+	uring.PrepClose(sqe, fd)
+	sqe.UserData.SetUint64(0x0004)
+
+	const N = 4
+	submitted, err := ring.SubmitAndWait(N)
+	if err != nil { /*...*/
+		log.Fatal(err)
+	}
+	println(submitted) // 1
+
+	var cqe *uring.IoUringCqe
+	for i := 1; i <= N; i++ {
+		err = ring.WaitCqe(&cqe)
+		if err != nil {
+			log.Fatal(err)
+		} // check also EINTR
+		if cqe == nil {
+			log.Fatal("CQE is NULL!")
+		}
+		log.Printf("CQE: %+#v\n", cqe)
+		if uring.UserData(i) != cqe.UserData {
+			panic("UNORDERED")
+		}
+
+		if cqe.Res < 0 {
+			panic(syscall.Errno(-cqe.Res))
+		}
+
+		if i == 0x0003 {
+			retvb := buf[:cqe.Res]
+			fmt.Printf("retv buf %+#v\n", retvb)
+			if !bytes.Equal(b, retvb) {
+				panic("RET BUF NOT EQ")
+			}
+		}
+
+		ring.SeenCqe(cqe)
+	}
+	_ = cqe.UserData
+	_ = cqe.Res
+	_ = cqe.Flags
+}

examples/read/read.go

@@ -1,48 +0,0 @@
-package main
-
-import (
-	"log"
-
-	"github.com/ii64/gouring"
-	"golang.org/x/sys/unix"
-)
-
-func main() {
-
-	h, err := gouring.New(256, 0)
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer h.Close()
-
-	fd, err := unix.Open("/tmp/test", unix.O_RDWR, 0677)
-
-	sqe := h.GetSqe()
-	b := make([]byte, 20)
-	gouring.PrepRead(sqe, fd, &b[0], len(b), 0)
-	log.Println("Buffer: ", b)
-
-	submitted, err := h.SubmitAndWait(1)
-	if err != nil {
-		log.Fatal(err)
-	}
-	println(submitted) // 1
-
-	var cqe *gouring.IoUringCqe
-	err = h.WaitCqe(&cqe)
-	if err != nil {
-		log.Fatal(err)
-	} // check also EINTR
-	if cqe == nil {
-		log.Fatal("CQE is NULL!")
-	}
-	h.SeenCqe(cqe)
-
-	log.Println("CQE: ", cqe)
-	log.Println("Buffer: ", b)
-	log.Println("Buffer: ", string(b))
-
-	_ = cqe.UserData
-	_ = cqe.Res
-	_ = cqe.Flags
-}

examples/write/write.go

@@ -1,44 +0,0 @@
-package main
-
-import (
-	"log"
-
-	"github.com/ii64/gouring"
-	"golang.org/x/sys/unix"
-)
-
-func main() {
-
-	h, err := gouring.New(256, 0)
-	if err != nil {
-		log.Fatal(err)
-	}
-	defer h.Close()
-
-	fd, err := unix.Open("/tmp/test", unix.O_RDWR, 0677)
-
-	sqe := h.GetSqe()
-	b := []byte("hello from io_uring!\n")
-	gouring.PrepWrite(sqe, fd, &b[0], len(b), 0)
-
-	submitted, err := h.SubmitAndWait(1)
-	if err != nil { /*...*/
-		log.Fatal(err)
-	}
-	println(submitted) // 1
-
-	var cqe *gouring.IoUringCqe
-	err = h.WaitCqe(&cqe)
-	if err != nil {
-		log.Fatal(err)
-	} // check also EINTR
-	if cqe == nil {
-		log.Fatal("CQE is NULL!")
-	}
-	log.Println(cqe)
-	h.SeenCqe(cqe)
-
-	_ = cqe.UserData
-	_ = cqe.Res
-	_ = cqe.Flags
-}

ioctl/hdr_ioctl.go

@@ -34,7 +34,7 @@ func IOC(dir, typ, nr, siz int) int {
 }
 
 /*
- IO ops
+	IO ops
 */
 
 //go:nosplit