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From: Shuah Khan <skhan@linuxfoundation.org>
To: Lars Gunnarsson <gunnarsson.lars@gmail.com>,
	Valentina Manea <valentina.manea.m@gmail.com>,
	Shuah Khan <shuah@kernel.org>,
	linux-usb@vger.kernel.org, Shuah Khan <skhan@linuxfoundation.org>
Subject: Re: [PATCH v1 1/3] tools/usbip: support use case reconnect: prepare
Date: Wed, 6 Oct 2021 17:37:15 -0600	[thread overview]
Message-ID: <74efa67e-2b2e-3a6e-3bc0-dbbb25197eef@linuxfoundation.org> (raw)
In-Reply-To: <20211006204817.GA43927@dell-precision-T3610>

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

  reply	other threads:[~2021-10-06 23:37 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-06 20:48 [PATCH v1 1/3] tools/usbip: support use case reconnect: prepare Lars Gunnarsson
2021-10-06 23:37 ` Shuah Khan [this message]
2021-10-07 21:04   ` Lars Gunnarsson
2021-10-07  5:33 ` Greg KH

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