Re: [PATCH v1 1/3] tools/usbip: support use case reconnect: prepare

Lars Gunnarsson
2021-10-07T21:04:10Z

Hi Shuah,

Thanks for the comments and for quick response. I'll send a new
patch set from the comments.

Best regards, Lars

On Wed, Oct 06, 2021 at 05:37:15PM -0600, Shuah Khan wrote:
> On 10/6/21 2:48 PM, Lars Gunnarsson wrote:
> > This patch implements an usb monitor into libusbip to await usb events,
> > example connect and disconnect.
> >
>
> Please describe the use-case adding more details. When and how user
> would use this?
>
> This will also require doc and man page changes.
>
> > Signed-off-by: Lars Gunnarsson <gunnarsson.lars@gmail.com>
> > ---
> > tools/usb/usbip/.gitignore | 1 +
> > tools/usb/usbip/libsrc/Makefile.am | 3 +-
> > tools/usb/usbip/libsrc/usbip_common.h | 1 +
> > tools/usb/usbip/libsrc/usbip_monitor.c | 147 +++++++++++++++++++++++++
> > tools/usb/usbip/libsrc/usbip_monitor.h | 21 ++++
> > 5 files changed, 172 insertions(+), 1 deletion(-)
> > create mode 100644 tools/usb/usbip/libsrc/usbip_monitor.c
> > create mode 100644 tools/usb/usbip/libsrc/usbip_monitor.h
> >
> > diff --git a/tools/usb/usbip/.gitignore b/tools/usb/usbip/.gitignore
> > index 597361a96dbb..6304adefb5e1 100644
> > --- a/tools/usb/usbip/.gitignore
> > +++ b/tools/usb/usbip/.gitignore
> > @@ -28,6 +28,7 @@ libsrc/libusbip_la-usbip_common.lo
> > libsrc/libusbip_la-usbip_device_driver.lo
> > libsrc/libusbip_la-usbip_host_common.lo
> > libsrc/libusbip_la-usbip_host_driver.lo
> > +libsrc/libusbip_la-usbip_monitor.lo
> > libsrc/libusbip_la-vhci_driver.lo
> > src/usbip
> > src/usbipd
> > diff --git a/tools/usb/usbip/libsrc/Makefile.am b/tools/usb/usbip/libsrc/Makefile.am
> > index dabd2c91d311..3e31e33729cf 100644
> > --- a/tools/usb/usbip/libsrc/Makefile.am
> > +++ b/tools/usb/usbip/libsrc/Makefile.am
> > @@ -8,4 +8,5 @@ libusbip_la_SOURCES := names.c names.h usbip_host_driver.c usbip_host_driver.h \
> > usbip_device_driver.c usbip_device_driver.h \
> > usbip_common.c usbip_common.h usbip_host_common.h \
> > usbip_host_common.c vhci_driver.c vhci_driver.h \
> > - sysfs_utils.c sysfs_utils.h
> > + sysfs_utils.c sysfs_utils.h \
> > + usbip_monitor.c
> > diff --git a/tools/usb/usbip/libsrc/usbip_common.h b/tools/usb/usbip/libsrc/usbip_common.h
> > index 73a367a7fa10..13f1d4ca47c5 100644
> > --- a/tools/usb/usbip/libsrc/usbip_common.h
> > +++ b/tools/usb/usbip/libsrc/usbip_common.hudev_driver
> > @@ -30,6 +30,7 @@
> > /* kernel module names */
> > #define USBIP_CORE_MOD_NAME "usbip-core"
> > +#define USBIP_USB_DRV_NAME "usb"
> > #define USBIP_HOST_DRV_NAME "usbip-host"
> > #define USBIP_DEVICE_DRV_NAME "usbip-vudc"
> > #define USBIP_VHCI_DRV_NAME "vhci_hcd"
> > diff --git a/tools/usb/usbip/libsrc/usbip_monitor.c b/tools/usb/usbip/libsrc/usbip_monitor.c
> > new file mode 100644
> > index 000000000000..731d344f2965
> > --- /dev/null
> > +++ b/tools/usb/usbip/libsrc/usbip_monitor.c
> > @@ -0,0 +1,147 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> I am seeing several coding style problems in these patches.
> inclduing Improper SPDX comment style
>
> > +/**
> > + * Copyright (C) 2021 Lars Gunnarsson
> > + */
> > +#include <libudev.h>
> > +#include <stdlib.h>
> > +#include <string.h>
> > +#include <sys/poll.h>
> > +
> > +#include "usbip_monitor.h"
> > +
> > +static const size_t MAX_STRLEN = 32;
>
> Let's not add new constants. Take a look at how existing code
> is checking return values for udev_device_get_action(),
> udev_device_get_driver() and udev_device_get_sysname() and match
> it.
>
> > +
> > +struct usbip_monitor {
> > + const char *busid;
> > + struct udev *udev;
> > + struct udev_monitor *udev_monitor;
> > +};
> > +
> > +usbip_monitor_t *usbip_monitor_new(void)
> > +{
> > + usbip_monitor_t *monitor = NULL;
> > + struct udev *udev = udev_new();
> > +
> > + if (udev) {
> > + struct udev_monitor *udev_monitor =
> > + udev_monitor_new_from_netlink(udev, "udev");
> > + udev_monitor_filter_add_match_subsystem_devtype(
> > + udev_monitor,
> > + /*subsystem=*/"usb",
> > + /*devtype=*/"usb_device");
> > + udev_monitor_enable_receiving(udev_monitor);
> > + monitor = malloc(sizeof(struct usbip_monitor));
> > + monitor->busid = NULL;
> > + monitor->udev = udev;
> > + monitor->udev_monitor = udev_monitor;
> > + }
> > + return monitor;
> > +}
> > +
> > +void usbip_monitor_delete(usbip_monitor_t *monitor)
> > +{
> > + if (monitor) {
> > + udev_monitor_unref(monitor->udev_monitor);
> > + udev_unref(monitor->udev);
> > + free(monitor);
> > + }
> > +}
> > +
> > +void usbip_monitor_set_busid(usbip_monitor_t *monitor, const char *busid)
> > +{
> > + monitor->busid = busid;
> > +}
> > +
> > +static struct udev_device *await_udev_event(const usbip_monitor_t *monitor)
> > +{
> > + struct udev_device *dev = NULL;
> > + int fd = udev_monitor_get_fd(monitor->udev_monitor);
> > + const int timeout = -1;
> > + const int nfds = 1; // number of file descriptors
> > + struct pollfd pollfd[] = { { fd, POLLIN, 0 } };
> > + int nfd = poll(pollfd, nfds, timeout);
> > +
> > + if (nfd) {
> > + dev = udev_monitor_receive_device(monitor->udev_monitor);
> > + }
> > + return dev;
> > +}
> > +
> > +static int optional_filter_busid(const char *busid, const char *udev_busid)
> > +{
> > + int filter_match = 0;
> > +
> > + if (busid) {
> > + if (strncmp(busid, udev_busid, MAX_STRLEN) == 0) {
> > + filter_match = 1;
> > + }
> > + } else {
> > + filter_match = 1;
> > + }
> > + return filter_match;
> > +}
> > +
> > +static void await_usb_with_driver(const usbip_monitor_t *monitor,
> > + const char *driver, const char *action)
> > +{
> > + while (1) {
> > + struct udev_device *dev = await_udev_event(monitor);
> > +
> > + if (dev) {
> > + const char *udev_action = udev_device_get_action(dev);
> > + const char *udev_driver = udev_device_get_driver(dev);
> > + const char *udev_busid = udev_device_get_sysname(dev);
> > +
> > + if (strncmp(udev_action, action, MAX_STRLEN) == 0 &&
> > + strncmp(udev_driver, driver, MAX_STRLEN) == 0) {
>
> Braces {} are not necessary for single statement blocks
>
> > + if (optional_filter_busid(monitor->busid,
> > + udev_busid)) {
> > + break;
> > + }
> > + }
> > + udev_device_unref(dev);
> > + }
> > + }
> > +}
> > +
> > +void usbip_monitor_await_usb_add(const usbip_monitor_t *monitor,
> > + const char *driver)
> > +{
> > + await_usb_with_driver(monitor, driver, "add");
> > +}
> > +
> > +void usbip_monitor_await_usb_bind(const usbip_monitor_t *monitor,
> > + const char *driver)
> > +{
> > + await_usb_with_driver(monitor, driver, "bind");
> > +}
> > +
> > +static void await_usb(const usbip_monitor_t *monitor, const char *action)
> > +{
> > + while (1) {
> > + struct udev_device *dev = await_udev_event(monitor);
> > +
> > + if (dev) {
> > + const char *udev_action = udev_device_get_action(dev);
> > + const char *udev_busid = udev_device_get_sysname(dev);
> > +
> > + if (strncmp(udev_action, action, MAX_STRLEN) == 0) {
> > + if (optional_filter_busid(monitor->busid,
> > + udev_busid)) {
> > + break;
> > + }
> > + }
> > + udev_device_unref(dev);
> > + }
> > + }
> > +}
> > +
> > +void usbip_monitor_await_usb_unbind(const usbip_monitor_t *monitor)
> > +{
> > + await_usb(monitor, "unbind");
> > +}
> > +
> > +void usbip_monitor_await_usb_delete(const usbip_monitor_t *monitor)
> > +{
> > + await_usb(monitor, "delete");
> > +}
> > diff --git a/tools/usb/usbip/libsrc/usbip_monitor.h b/tools/usb/usbip/libsrc/usbip_monitor.h
> > new file mode 100644
> > index 000000000000..474b95c80452
> > --- /dev/null
> > +++ b/tools/usb/usbip/libsrc/usbip_monitor.h
> > @@ -0,0 +1,21 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/**
> > + * Copyright (C) 2021 Lars Gunnarsson
> > + */
> > +#ifndef __USBIP_MONITOR_H
> > +#define __USBIP_MONITOR_H
> > +
> > +typedef struct usbip_monitor usbip_monitor_t;
>
> Let's not add a new typedef
> > +
> > +usbip_monitor_t *usbip_monitor_new(void);
> > +void usbip_monitor_delete(usbip_monitor_t *monitor);
> > +
> > +void usbip_monitor_set_busid(usbip_monitor_t *monitor, const char *busid);
> > +void usbip_monitor_await_usb_add(const usbip_monitor_t *monitor,
> > + const char *driver);
> > +void usbip_monitor_await_usb_bind(const usbip_monitor_t *monitor,
> > + const char *driver);
> > +void usbip_monitor_await_usb_unbind(const usbip_monitor_t *monitor);
> > +void usbip_monitor_await_usb_delete(const usbip_monitor_t *monitor);
> > +
> > +#endif /* __USBIP_MONITOR_H */
> >
>
> Please run checkpatch on all of these 3 patches and fix the problems.
> Also add doc and man pages describing the feature you are adding more
> clearly.
>
> thanks,
> -- Shuah