Re: [PATCH v4 2/3] net/9p/usbg: Add new usb gadget function transport

Andrzej Pietrasiewicz
2024-05-10T09:25:55Z

Hi Michael,

W dniu 30.04.2024 o 01:33, Michael Grzeschik pisze:
> Add the new gadget function for 9pfs transport. This function is
> defining an simple 9pfs transport interface that consists of one in and
> one out endpoint. The endpoints transmit and receive the 9pfs protocol
> payload when mounting a 9p filesystem over usb.
>
> Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
>
> ---
> v3 -> v4:
> - implemented conn_cancel

I tried this scenario:

1) run all the components and have 9pfs up and running
2) stop the forwarder
3) umount -f at the gadget side - this indeed succeeds now in v4
4) start the forwarder again
5) mount at the gadget side - this hangs.

Did this scenario work for you?

Regards,

Andrzej

> - moved from mount_tag to device name like ffs does
> - renamed function_list to usb9pfs_instance
> - renamed usbg_function_list to usb9pfs_instance_list
> - renamed rx/tx_fill to queue_rx/tx
> - added use of retvals
> - added locking comment over usb9pfs_transmit
> - using if_else instead of two pathed switch calls
> - fixed return values of completion handler
> - using void pointer as parameter in rx_header
> - added a missed req_put in rx_header
> - removed extra disable function but call disable_ep directly
> - repaired several return values
> - remove the suspicious disable / enable path in usbg_create
> v2 -> v3: -
> v1 -> v2:
> - move the driver to net/9p/trans_usbg.c
> - fixed the commit title
> - fix %zu usage in p9_debug for size_t type
> - define functions static that are only used localy
> - return 0 in alloc_requests
> - use id_alloc_max instead of ida_simple_get
> - call ida_free in usb9pfs_free_func
> - call kfree for usb9pfs->tag and usb9pfs in usb9pfs_free_func
> - add MODULE_ALIAS_9P to load this module automatic when mounting
> - improved the documentation
> - added depends on USB_GADGET in Kconfig
> ---
> Documentation/filesystems/9p.rst | 17 +-
> net/9p/Kconfig | 6 +
> net/9p/Makefile | 4 +
> net/9p/trans_usbg.c | 983 +++++++++++++++++++++++++++++++++++++++
> 4 files changed, 1009 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/filesystems/9p.rst b/Documentation/filesystems/9p.rst
> index 1e0e0bb6fdf91..10cf79dc287f8 100644
> --- a/Documentation/filesystems/9p.rst
> +++ b/Documentation/filesystems/9p.rst
> @@ -48,11 +48,25 @@ For server running on QEMU host with virtio transport::
>
> mount -t 9p -o trans=virtio <mount_tag> /mnt/9
>
> -where mount_tag is the tag associated by the server to each of the exported
> +where mount_tag is the tag generated by the server to each of the exported
> mount points. Each 9P export is seen by the client as a virtio device with an
> associated "mount_tag" property. Available mount tags can be
> seen by reading /sys/bus/virtio/drivers/9pnet_virtio/virtio<n>/mount_tag files.
>
> +USBG Usage
> +==========
> +
> +To mount a 9p FS on a USB Host accessible via the gadget at runtime::
> +
> + mount -t 9p -o trans=usbg,aname=/path/to/fs <device> /mnt/9
> +
> +To mount a 9p FS on a USB Host accessible via the gadget as root filesystem::
> +
> + root=<device> rootfstype=9p rootflags=trans=usbg,cache=loose,uname=root,access=0,dfltuid=0,dfltgid=0,aname=/path/to/rootfs
> +
> +where <device> is the tag associated by the usb gadget transport.
> +It is defined by the configfs instance name.
> +
> Options
> =======
>
> @@ -68,6 +82,7 @@ Options
> virtio connect to the next virtio channel available
> (from QEMU with trans_virtio module)
> rdma connect to a specified RDMA channel
> + usbg connect to a specified usb gadget channel
> ======== ============================================
>
> uname=name user name to attempt mount as on the remote server. The
> diff --git a/net/9p/Kconfig b/net/9p/Kconfig
> index 00ebce9e5a657..c3d357eb8bb37 100644
> --- a/net/9p/Kconfig
> +++ b/net/9p/Kconfig
> @@ -39,6 +39,12 @@ config NET_9P_XEN
> This builds support for a transport for 9pfs between
> two Xen domains.
>
> +config NET_9P_USBG
> + bool "9P USB Gadget Transport"
> + depends on USB_GADGET
> + help
> + This builds support for a transport for 9pfs over
> + usb gadget.
>
> config NET_9P_RDMA
> depends on INET && INFINIBAND && INFINIBAND_ADDR_TRANS
> diff --git a/net/9p/Makefile b/net/9p/Makefile
> index 1df9b344c30bd..22794a451c3f7 100644
> --- a/net/9p/Makefile
> +++ b/net/9p/Makefile
> @@ -4,6 +4,7 @@ obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
> obj-$(CONFIG_NET_9P_XEN) += 9pnet_xen.o
> obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
> obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
> +obj-$(CONFIG_NET_9P_USBG) += 9pnet_usbg.o
>
> 9pnet-objs := \
> mod.o \
> @@ -23,3 +24,6 @@ obj-$(CONFIG_NET_9P_RDMA) += 9pnet_rdma.o
>
> 9pnet_rdma-objs := \
> trans_rdma.o \
> +
> +9pnet_usbg-objs := \
> + trans_usbg.o \
> diff --git a/net/9p/trans_usbg.c b/net/9p/trans_usbg.c
> new file mode 100644
> index 0000000000000..bc440033cbe68
> --- /dev/null
> +++ b/net/9p/trans_usbg.c
> @@ -0,0 +1,983 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * trans_usbg.c - USB peripheral usb9pfs configuration driver and transport.
> + *
> + * Copyright (C) 2024 Michael Grzeschik <m.grzeschik@pengutronix.de>
> + */
> +
> +/* Gadget usb9pfs only needs two bulk endpoints, and will use the usb9pfs
> + * transport to mount host exported filesystem via usb gadget.
> + */
> +
> +/* +--------------------------+ | +--------------------------+
> + * | 9PFS mounting client | | | 9PFS exporting server |
> + * SW | | | | |
> + * | (this:trans_usbg) | | |(e.g. diod or nfs-ganesha)|
> + * +-------------^------------+ | +-------------^------------+
> + * | | |
> + * ------------------|------------------------------------|-------------
> + * | | |
> + * +-------------v------------+ | +-------------v------------+
> + * | | | | |
> + * HW | USB Device Controller <---------> USB Host Controller |
> + * | | | | |
> + * +--------------------------+ | +--------------------------+
> + */
> +
> +#include <linux/slab.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/usb/composite.h>
> +#include <linux/usb/u_f.h>
> +
> +#include <net/9p/9p.h>
> +#include <net/9p/client.h>
> +#include <net/9p/transport.h>
> +
> +#define DEFAULT_BUFLEN 16384
> +
> +struct f_usb9pfs {
> + struct p9_client *client;
> +
> + struct p9_req_t *p9_tx_req;
> +
> + struct list_head tx_req_list;
> +
> + /* 9p request lock for en/dequeue */
> + spinlock_t lock;
> + /* usb request lock for en/dequeue */
> + spinlock_t req_lock;
> +
> + struct usb_request *in_req;
> + struct usb_request *out_req;
> +
> + struct usb_ep *in_ep;
> + struct usb_ep *out_ep;
> +
> + unsigned int buflen;
> +
> + struct usb_function function;
> +};
> +
> +static inline struct f_usb9pfs *func_to_usb9pfs(struct usb_function *f)
> +{
> + return container_of(f, struct f_usb9pfs, function);
> +}
> +
> +struct f_usb9pfs_opts {
> + struct usb_function_instance func_inst;
> + unsigned int buflen;
> +
> + struct f_usb9pfs_dev *dev;
> +
> + /* Read/write access to configfs attributes is handled by configfs.
> + *
> + * This is to protect the data from concurrent access by read/write
> + * and create symlink/remove symlink.
> + */
> + struct mutex lock;
> + int refcnt;
> +};
> +
> +struct f_usb9pfs_dev {
> + struct f_usb9pfs *usb9pfs;
> + struct f_usb9pfs_opts *opts;
> + char tag[41];
> + bool inuse;
> +
> + struct list_head usb9pfs_instance;
> +};
> +
> +static DEFINE_MUTEX(usb9pfs_lock);
> +static struct list_head usbg_instance_list;
> +
> +static int usb9pfs_queue_tx(struct f_usb9pfs *usb9pfs, struct usb_request *req,
> + gfp_t gfp_flags)
> +{
> + struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
> + int ret = -ENOMEM;
> +
> + if (!(usb9pfs->p9_tx_req->tc.size % usb9pfs->in_ep->maxpacket))
> + req->zero = 1;
> +
> + req->buf = usb9pfs->p9_tx_req->tc.sdata;
> + req->length = usb9pfs->p9_tx_req->tc.size;
> +
> + dev_dbg(&cdev->gadget->dev, "%s usb9pfs send --> %d/%d, zero: %d\n",
> + usb9pfs->in_ep->name, req->actual, req->length, req->zero);
> +
> + ret = usb_ep_queue(usb9pfs->in_ep, req, gfp_flags);
> +
> + dev_dbg(&cdev->gadget->dev, "tx submit --> %d\n", ret);
> +
> + return ret;
> +}
> +
> +static int usb9pfs_queue_rx(struct f_usb9pfs *usb9pfs, struct usb_request *req,
> + gfp_t gfp_flags)
> +{
> + struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
> + int ret = -ENOMEM;
> +
> + ret = usb_ep_queue(usb9pfs->out_ep, req, gfp_flags);
> +
> + dev_dbg(&cdev->gadget->dev, "rx submit --> %d\n", ret);
> +
> + return ret;
> +}
> +
> +/* This needs to be called with usb9pfs->req_lock held */
> +static int usb9pfs_transmit(struct f_usb9pfs *usb9pfs)
> +{
> + struct p9_req_t *p9_req = NULL;
> + unsigned long flags;
> + int ret = 0;
> +
> + spin_lock_irqsave(&usb9pfs->lock, flags);
> +
> + if (usb9pfs->p9_tx_req) {
> + spin_unlock_irqrestore(&usb9pfs->lock, flags);
> + return -EBUSY;
> + }
> +
> + p9_req = list_first_entry_or_null(&usb9pfs->tx_req_list,
> + struct p9_req_t, req_list);
> + if (!p9_req) {
> + spin_unlock_irqrestore(&usb9pfs->lock, flags);
> + return -ENOENT;
> + }
> +
> + list_del(&p9_req->req_list);
> +
> + usb9pfs->p9_tx_req = p9_req;
> +
> + p9_req_get(usb9pfs->p9_tx_req);
> +
> + ret = usb9pfs_queue_tx(usb9pfs, usb9pfs->in_req, GFP_ATOMIC);
> +
> + spin_unlock_irqrestore(&usb9pfs->lock, flags);
> +
> + return ret;
> +}
> +
> +static void usb9pfs_tx_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + struct f_usb9pfs *usb9pfs = ep->driver_data;
> + struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
> + int ret = 0;
> +
> + if (req->status) {
> + dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
> + ep->name, req->status, req->actual, req->length);
> + goto free_req;
> + }
> +
> + /* reset zero packages */
> + req->zero = 0;
> +
> + dev_dbg(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
> + ep->name, req->status, req->actual, req->length);
> +
> + spin_lock(&usb9pfs->req_lock);
> +
> + WRITE_ONCE(usb9pfs->p9_tx_req->status, REQ_STATUS_SENT);
> +
> + p9_req_put(usb9pfs->client, usb9pfs->p9_tx_req);
> +
> + ret = usb9pfs_queue_rx(usb9pfs, usb9pfs->out_req, GFP_ATOMIC);
> + if (ret) {
> + spin_unlock(&usb9pfs->req_lock);
> + goto free_req;
> + }
> +
> + spin_unlock(&usb9pfs->req_lock);
> +
> + return;
> +
> +free_req:
> + usb_ep_free_request(ep == usb9pfs->in_ep ?
> + usb9pfs->out_ep : usb9pfs->in_ep,
> + req->context);
> + free_ep_req(ep, req);
> +}
> +
> +static struct p9_req_t *usb9pfs_rx_header(struct f_usb9pfs *usb9pfs, void *buf)
> +{
> + struct p9_req_t *p9_rx_req;
> + struct p9_fcall rc;
> + int ret;
> +
> + /* start by reading header */
> + rc.sdata = buf;
> + rc.offset = 0;
> + rc.capacity = P9_HDRSZ;
> + rc.size = P9_HDRSZ;
> +
> + p9_debug(P9_DEBUG_TRANS, "mux %p got %zu bytes\n", usb9pfs,
> + rc.capacity - rc.offset);
> +
> + ret = p9_parse_header(&rc, &rc.size, NULL, NULL, 0);
> + if (ret) {
> + p9_debug(P9_DEBUG_ERROR,
> + "error parsing header: %d\n", ret);
> + return NULL;
> + }
> +
> + p9_debug(P9_DEBUG_TRANS,
> + "mux %p pkt: size: %d bytes tag: %d\n",
> + usb9pfs, rc.size, rc.tag);
> +
> + p9_rx_req = p9_tag_lookup(usb9pfs->client, rc.tag);
> + if (!p9_rx_req || p9_rx_req->status != REQ_STATUS_SENT) {
> + p9_debug(P9_DEBUG_ERROR, "Unexpected packet tag %d\n", rc.tag);
> + return NULL;
> + }
> +
> + if (rc.size > p9_rx_req->rc.capacity) {
> + p9_debug(P9_DEBUG_ERROR,
> + "requested packet size too big: %d for tag %d with capacity %zd\n",
> + rc.size, rc.tag, p9_rx_req->rc.capacity);
> + p9_req_put(usb9pfs->client, p9_rx_req);
> + return NULL;
> + }
> +
> + if (!p9_rx_req->rc.sdata) {
> + p9_debug(P9_DEBUG_ERROR,
> + "No recv fcall for tag %d (req %p), disconnecting!\n",
> + rc.tag, p9_rx_req);
> + p9_req_put(usb9pfs->client, p9_rx_req);
> + return NULL;
> + }
> +
> + return p9_rx_req;
> +}
> +
> +static void usb9pfs_rx_complete(struct usb_ep *ep, struct usb_request *req)
> +{
> + struct f_usb9pfs *usb9pfs = ep->driver_data;
> + struct usb_composite_dev *cdev = usb9pfs->function.config->cdev;
> + struct p9_req_t *p9_rx_req;
> + unsigned long flags;
> + int ret = 0;
> +
> + if (req->status) {
> + dev_err(&cdev->gadget->dev, "%s usb9pfs complete --> %d, %d/%d\n",
> + ep->name, req->status, req->actual, req->length);
> + goto free_req;
> + }
> +
> + spin_lock_irqsave(&usb9pfs->req_lock, flags);
> +
> + p9_rx_req = usb9pfs_rx_header(usb9pfs, req->buf);
> + if (!p9_rx_req) {
> + spin_unlock_irqrestore(&usb9pfs->req_lock, flags);
> + goto free_req;
> + }
> +
> + memcpy(p9_rx_req->rc.sdata, req->buf, req->actual);
> +
> + p9_rx_req->rc.size = req->actual;
> +
> + p9_client_cb(usb9pfs->client, p9_rx_req, REQ_STATUS_RCVD);
> + p9_req_put(usb9pfs->client, p9_rx_req);
> +
> + usb9pfs->p9_tx_req = NULL;
> +
> + ret = usb9pfs_transmit(usb9pfs);
> + if (ret) {
> + spin_unlock_irqrestore(&usb9pfs->req_lock, flags);
> + return;
> + }
> +
> + spin_unlock_irqrestore(&usb9pfs->req_lock, flags);
> +
> + return;
> +
> +free_req:
> + usb_ep_free_request(ep == usb9pfs->in_ep ?
> + usb9pfs->out_ep : usb9pfs->in_ep,
> + req->context);
> + free_ep_req(ep, req);
> +
> + p9_client_cb(usb9pfs->client, p9_rx_req, REQ_STATUS_ERROR);
> +}
> +
> +static void disable_ep(struct usb_composite_dev *cdev, struct usb_ep *ep)
> +{
> + int value;
> +
> + value = usb_ep_disable(ep);
> + if (value < 0)
> + dev_info(&cdev->gadget->dev,
> + "disable %s --> %d\n", ep->name, value);
> +}
> +
> +static void disable_usb9pfs(struct f_usb9pfs *usb9pfs)
> +{
> + struct usb_composite_dev *cdev =
> + usb9pfs->function.config->cdev;
> +
> + disable_ep(cdev, usb9pfs->in_ep);
> + disable_ep(cdev, usb9pfs->out_ep);
> + dev_dbg(&cdev->gadget->dev, "%s disabled\n",
> + usb9pfs->function.name);
> +}
> +
> +static int alloc_requests(struct usb_composite_dev *cdev,
> + struct f_usb9pfs *usb9pfs)
> +{
> + int ret = 0;
> +
> + usb9pfs->in_req = usb_ep_alloc_request(usb9pfs->in_ep, GFP_ATOMIC);
> + if (!usb9pfs->in_req) {
> + ret = -ENOENT;
> + goto fail;
> + }
> +
> + usb9pfs->out_req = alloc_ep_req(usb9pfs->out_ep, usb9pfs->buflen);
> + if (!usb9pfs->out_req) {
> + ret = -ENOENT;
> + goto fail_in;
> + }
> +
> + usb9pfs->in_req->complete = usb9pfs_tx_complete;
> + usb9pfs->out_req->complete = usb9pfs_rx_complete;
> +
> + /* length will be set in complete routine */
> + usb9pfs->in_req->context = usb9pfs;
> + usb9pfs->out_req->context = usb9pfs;
> +
> + return ret;
> +
> +fail_in:
> + usb_ep_free_request(usb9pfs->in_ep, usb9pfs->in_req);
> +fail:
> + return ret;
> +}
> +
> +static int enable_endpoint(struct usb_composite_dev *cdev,
> + struct f_usb9pfs *usb9pfs, struct usb_ep *ep)
> +{
> + int ret;
> +
> + ret = config_ep_by_speed(cdev->gadget, &usb9pfs->function, ep);
> + if (ret)
> + return ret;
> +
> + ret = usb_ep_enable(ep);
> + if (ret < 0)
> + return ret;
> +
> + ep->driver_data = usb9pfs;
> +
> + return ret;
> +}
> +
> +static int
> +enable_usb9pfs(struct usb_composite_dev *cdev, struct f_usb9pfs *usb9pfs)
> +{
> + int result = 0;
> +
> + result = enable_endpoint(cdev, usb9pfs, usb9pfs->in_ep);
> + if (result)
> + goto out;
> +
> + result = enable_endpoint(cdev, usb9pfs, usb9pfs->out_ep);
> + if (result)
> + goto disable_in;
> +
> + result = alloc_requests(cdev, usb9pfs);
> + if (result)
> + goto disable_out;
> +
> + dev_dbg(&cdev->gadget->dev, "%s enabled\n", usb9pfs->function.name);
> + return 0;
> +
> +disable_out:
> + usb_ep_disable(usb9pfs->out_ep);
> +disable_in:
> + usb_ep_disable(usb9pfs->in_ep);
> +out:
> + return result;
> +}
> +
> +static int p9_usbg_create(struct p9_client *client, const char *devname, char *args)
> +{
> + struct usb_composite_dev *cdev;
> + struct f_usb9pfs_dev *dev;
> + struct f_usb9pfs_dev *tmp;
> + struct f_usb9pfs *usb9pfs;
> + struct usb_function *f;
> + int ret = -ENOENT;
> + int found = 0;
> +
> + if (!devname)
> + return -EINVAL;
> +
> + mutex_lock(&usb9pfs_lock);
> + list_for_each_entry_safe(dev, tmp, &usbg_instance_list, usb9pfs_instance) {
> + if (!strncmp(devname, dev->tag, strlen(devname))) {
> + if (!dev->inuse) {
> + dev->inuse = true;
> + found = 1;
> + break;
> + }
> + ret = -EBUSY;
> + break;
> + }
> + }
> + mutex_unlock(&usb9pfs_lock);
> +
> + if (!found) {
> + pr_err("no channels available for device %s\n", devname);
> + return ret;
> + }
> +
> + usb9pfs = dev->usb9pfs;
> + if (!usb9pfs)
> + return -EINVAL;
> +
> + INIT_LIST_HEAD(&usb9pfs->tx_req_list);
> +
> + spin_lock_init(&usb9pfs->lock);
> + spin_lock_init(&usb9pfs->req_lock);
> +
> + f = &usb9pfs->function;
> + cdev = f->config->cdev;
> +
> + client->trans = (void *)usb9pfs;
> + client->status = Connected;
> + usb9pfs->client = client;
> +
> + client->trans_mod->maxsize = usb9pfs->buflen;
> +
> + return enable_usb9pfs(cdev, usb9pfs);
> +}
> +
> +static void p9_usbg_close(struct p9_client *client)
> +{
> + struct f_usb9pfs *usb9pfs;
> + struct f_usb9pfs_dev *dev;
> + struct p9_req_t *req;
> + struct f_usb9pfs_opts *opts;
> +
> + if (!client)
> + return;
> +
> + usb9pfs = client->trans;
> + if (!usb9pfs)
> + return;
> +
> + client->status = Disconnected;
> +
> + spin_lock(&usb9pfs->req_lock);
> +
> + req = usb9pfs->p9_tx_req;
> + if (req) {
> + if (!req->t_err)
> + req->t_err = -ECONNRESET;
> + p9_client_cb(usb9pfs->client, req, REQ_STATUS_ERROR);
> + }
> +
> + spin_unlock(&usb9pfs->req_lock);
> +
> + disable_usb9pfs(usb9pfs);
> +
> + opts = container_of(usb9pfs->function.fi,
> + struct f_usb9pfs_opts, func_inst);
> +
> + dev = opts->dev;
> +
> + mutex_lock(&usb9pfs_lock);
> + dev->inuse = false;
> + mutex_unlock(&usb9pfs_lock);
> +}
> +
> +static int p9_usbg_request(struct p9_client *client, struct p9_req_t *p9_req)
> +{
> + struct f_usb9pfs *usb9pfs = client->trans;
> + unsigned long flags;
> +
> + if (client->status != Connected)
> + return -EBUSY;
> +
> + spin_lock_irqsave(&usb9pfs->lock, flags);
> + list_add_tail(&p9_req->req_list, &usb9pfs->tx_req_list);
> + spin_unlock_irqrestore(&usb9pfs->lock, flags);
> +
> + spin_lock_irqsave(&usb9pfs->req_lock, flags);
> + usb9pfs_transmit(usb9pfs);
> + spin_unlock_irqrestore(&usb9pfs->req_lock, flags);
> +
> + return 0;
> +}
> +
> +static int p9_usbg_cancel(struct p9_client *client, struct p9_req_t *req)
> +{
> + struct f_usb9pfs *usb9pfs = client->trans;
> + int ret = 1;
> +
> + p9_debug(P9_DEBUG_TRANS, "client %p req %p\n", client, req);
> +
> + spin_lock(&usb9pfs->req_lock);
> +
> + if (req->status == REQ_STATUS_UNSENT) {
> + list_del(&req->req_list);
> + WRITE_ONCE(req->status, REQ_STATUS_FLSHD);
> + p9_req_put(client, req);
> + ret = 0;
> + }
> + spin_unlock(&usb9pfs->req_lock);
> +
> + return ret;
> +}
> +
> +static struct p9_trans_module p9_usbg_trans = {
> + .name = "usbg",
> + .create = p9_usbg_create,
> + .close = p9_usbg_close,
> + .request = p9_usbg_request,
> + .cancel = p9_usbg_cancel,
> + .owner = THIS_MODULE,
> +};
> +
> +/*-------------------------------------------------------------------------*/
> +
> +#define USB_PROTOCOL_9PFS 0x09
> +
> +static struct usb_interface_descriptor usb9pfs_intf = {
> + .bLength = sizeof(usb9pfs_intf),
> + .bDescriptorType = USB_DT_INTERFACE,
> +
> + .bNumEndpoints = 2,
> + .bInterfaceClass = USB_CLASS_VENDOR_SPEC,
> + .bInterfaceSubClass = USB_SUBCLASS_VENDOR_SPEC,
> + .bInterfaceProtocol = USB_PROTOCOL_9PFS,
> +
> + /* .iInterface = DYNAMIC */
> +};
> +
> +/* full speed support: */
> +
> +static struct usb_endpoint_descriptor fs_usb9pfs_source_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bEndpointAddress = USB_DIR_IN,
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> +};
> +
> +static struct usb_endpoint_descriptor fs_usb9pfs_sink_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bEndpointAddress = USB_DIR_OUT,
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> +};
> +
> +static struct usb_descriptor_header *fs_usb9pfs_descs[] = {
> + (struct usb_descriptor_header *)&usb9pfs_intf,
> + (struct usb_descriptor_header *)&fs_usb9pfs_sink_desc,
> + (struct usb_descriptor_header *)&fs_usb9pfs_source_desc,
> + NULL,
> +};
> +
> +/* high speed support: */
> +
> +static struct usb_endpoint_descriptor hs_usb9pfs_source_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(512),
> +};
> +
> +static struct usb_endpoint_descriptor hs_usb9pfs_sink_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(512),
> +};
> +
> +static struct usb_descriptor_header *hs_usb9pfs_descs[] = {
> + (struct usb_descriptor_header *)&usb9pfs_intf,
> + (struct usb_descriptor_header *)&hs_usb9pfs_source_desc,
> + (struct usb_descriptor_header *)&hs_usb9pfs_sink_desc,
> + NULL,
> +};
> +
> +/* super speed support: */
> +
> +static struct usb_endpoint_descriptor ss_usb9pfs_source_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(1024),
> +};
> +
> +static struct usb_ss_ep_comp_descriptor ss_usb9pfs_source_comp_desc = {
> + .bLength = USB_DT_SS_EP_COMP_SIZE,
> + .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
> + .bMaxBurst = 0,
> + .bmAttributes = 0,
> + .wBytesPerInterval = 0,
> +};
> +
> +static struct usb_endpoint_descriptor ss_usb9pfs_sink_desc = {
> + .bLength = USB_DT_ENDPOINT_SIZE,
> + .bDescriptorType = USB_DT_ENDPOINT,
> +
> + .bmAttributes = USB_ENDPOINT_XFER_BULK,
> + .wMaxPacketSize = cpu_to_le16(1024),
> +};
> +
> +static struct usb_ss_ep_comp_descriptor ss_usb9pfs_sink_comp_desc = {
> + .bLength = USB_DT_SS_EP_COMP_SIZE,
> + .bDescriptorType = USB_DT_SS_ENDPOINT_COMP,
> + .bMaxBurst = 0,
> + .bmAttributes = 0,
> + .wBytesPerInterval = 0,
> +};
> +
> +static struct usb_descriptor_header *ss_usb9pfs_descs[] = {
> + (struct usb_descriptor_header *)&usb9pfs_intf,
> + (struct usb_descriptor_header *)&ss_usb9pfs_source_desc,
> + (struct usb_descriptor_header *)&ss_usb9pfs_source_comp_desc,
> + (struct usb_descriptor_header *)&ss_usb9pfs_sink_desc,
> + (struct usb_descriptor_header *)&ss_usb9pfs_sink_comp_desc,
> + NULL,
> +};
> +
> +/* function-specific strings: */
> +static struct usb_string strings_usb9pfs[] = {
> + [0].s = "usb9pfs input to output",
> + { } /* end of list */
> +};
> +
> +static struct usb_gadget_strings stringtab_usb9pfs = {
> + .language = 0x0409, /* en-us */
> + .strings = strings_usb9pfs,
> +};
> +
> +static struct usb_gadget_strings *usb9pfs_strings[] = {
> + &stringtab_usb9pfs,
> + NULL,
> +};
> +
> +/*-------------------------------------------------------------------------*/
> +
> +static int usb9pfs_func_bind(struct usb_configuration *c,
> + struct usb_function *f)
> +{
> + struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
> + struct f_usb9pfs_opts *opts;
> + struct usb_composite_dev *cdev = c->cdev;
> + int ret;
> + int id;
> +
> + /* allocate interface ID(s) */
> + id = usb_interface_id(c, f);
> + if (id < 0)
> + return id;
> + usb9pfs_intf.bInterfaceNumber = id;
> +
> + id = usb_string_id(cdev);
> + if (id < 0)
> + return id;
> + strings_usb9pfs[0].id = id;
> + usb9pfs_intf.iInterface = id;
> +
> + /* allocate endpoints */
> + usb9pfs->in_ep = usb_ep_autoconfig(cdev->gadget,
> + &fs_usb9pfs_source_desc);
> + if (!usb9pfs->in_ep)
> + goto autoconf_fail;
> +
> + usb9pfs->out_ep = usb_ep_autoconfig(cdev->gadget,
> + &fs_usb9pfs_sink_desc);
> + if (!usb9pfs->out_ep)
> + goto autoconf_fail;
> +
> + /* support high speed hardware */
> + hs_usb9pfs_source_desc.bEndpointAddress =
> + fs_usb9pfs_source_desc.bEndpointAddress;
> + hs_usb9pfs_sink_desc.bEndpointAddress =
> + fs_usb9pfs_sink_desc.bEndpointAddress;
> +
> + /* support super speed hardware */
> + ss_usb9pfs_source_desc.bEndpointAddress =
> + fs_usb9pfs_source_desc.bEndpointAddress;
> + ss_usb9pfs_sink_desc.bEndpointAddress =
> + fs_usb9pfs_sink_desc.bEndpointAddress;
> +
> + ret = usb_assign_descriptors(f, fs_usb9pfs_descs, hs_usb9pfs_descs,
> + ss_usb9pfs_descs, ss_usb9pfs_descs);
> + if (ret)
> + return ret;
> +
> + opts = container_of(f->fi, struct f_usb9pfs_opts, func_inst);
> + opts->dev->usb9pfs = usb9pfs;
> +
> + dev_dbg(&cdev->gadget->dev, "%s speed %s: IN/%s, OUT/%s\n",
> + (gadget_is_superspeed(c->cdev->gadget) ? "super" :
> + (gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full")),
> + f->name, usb9pfs->in_ep->name, usb9pfs->out_ep->name);
> +
> + return 0;
> +
> +autoconf_fail:
> + ERROR(cdev, "%s: can't autoconfigure on %s\n",
> + f->name, cdev->gadget->name);
> + return -ENODEV;
> +}
> +
> +static void usb9pfs_free_func(struct usb_function *f)
> +{
> + struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
> + struct f_usb9pfs_opts *opts;
> +
> + kfree(usb9pfs);
> +
> + opts = container_of(f->fi, struct f_usb9pfs_opts, func_inst);
> +
> + mutex_lock(&opts->lock);
> + opts->refcnt--;
> + mutex_unlock(&opts->lock);
> +
> + usb_free_all_descriptors(f);
> +}
> +
> +static int usb9pfs_set_alt(struct usb_function *f,
> + unsigned int intf, unsigned int alt)
> +{
> + return 0;
> +}
> +
> +static void usb9pfs_disable(struct usb_function *f)
> +{
> + struct f_usb9pfs *usb9pfs = func_to_usb9pfs(f);
> + struct p9_req_t *req;
> +
> + spin_lock(&usb9pfs->req_lock);
> +
> + req = usb9pfs->p9_tx_req;
> +
> + if (!req->t_err)
> + req->t_err = -ECONNRESET;
> + p9_client_cb(usb9pfs->client, req, REQ_STATUS_ERROR);
> +
> + spin_unlock(&usb9pfs->req_lock);
> +}
> +
> +static struct usb_function *usb9pfs_alloc(struct usb_function_instance *fi)
> +{
> + struct f_usb9pfs_opts *usb9pfs_opts;
> + struct f_usb9pfs *usb9pfs;
> +
> + usb9pfs = kzalloc(sizeof(*usb9pfs), GFP_KERNEL);
> + if (!usb9pfs)
> + return ERR_PTR(-ENOMEM);
> +
> + usb9pfs_opts = container_of(fi, struct f_usb9pfs_opts, func_inst);
> +
> + mutex_lock(&usb9pfs_opts->lock);
> + usb9pfs_opts->refcnt++;
> + mutex_unlock(&usb9pfs_opts->lock);
> +
> + usb9pfs->buflen = usb9pfs_opts->buflen;
> +
> + usb9pfs->function.name = "usb9pfs";
> + usb9pfs->function.bind = usb9pfs_func_bind;
> + usb9pfs->function.set_alt = usb9pfs_set_alt;
> + usb9pfs->function.disable = usb9pfs_disable;
> + usb9pfs->function.strings = usb9pfs_strings;
> +
> + usb9pfs->function.free_func = usb9pfs_free_func;
> +
> + return &usb9pfs->function;
> +}
> +
> +static inline struct f_usb9pfs_opts *to_f_usb9pfs_opts(struct config_item *item)
> +{
> + return container_of(to_config_group(item), struct f_usb9pfs_opts,
> + func_inst.group);
> +}
> +
> +static inline struct f_usb9pfs_opts *fi_to_f_usb9pfs_opts(struct usb_function_instance *fi)
> +{
> + return container_of(fi, struct f_usb9pfs_opts, func_inst);
> +}
> +
> +static void usb9pfs_attr_release(struct config_item *item)
> +{
> + struct f_usb9pfs_opts *usb9pfs_opts = to_f_usb9pfs_opts(item);
> +
> + usb_put_function_instance(&usb9pfs_opts->func_inst);
> +}
> +
> +static struct configfs_item_operations usb9pfs_item_ops = {
> + .release = usb9pfs_attr_release,
> +};
> +
> +static ssize_t f_usb9pfs_opts_buflen_show(struct config_item *item, char *page)
> +{
> + struct f_usb9pfs_opts *opts = to_f_usb9pfs_opts(item);
> + int result;
> +
> + mutex_lock(&opts->lock);
> + result = sprintf(page, "%d\n", opts->buflen);
> + mutex_unlock(&opts->lock);
> +
> + return result;
> +}
> +
> +static ssize_t f_usb9pfs_opts_buflen_store(struct config_item *item,
> + const char *page, size_t len)
> +{
> + struct f_usb9pfs_opts *opts = to_f_usb9pfs_opts(item);
> + int ret;
> + u32 num;
> +
> + mutex_lock(&opts->lock);
> + if (opts->refcnt) {
> + ret = -EBUSY;
> + goto end;
> + }
> +
> + ret = kstrtou32(page, 0, &num);
> + if (ret)
> + goto end;
> +
> + opts->buflen = num;
> + ret = len;
> +end:
> + mutex_unlock(&opts->lock);
> + return ret;
> +}
> +
> +CONFIGFS_ATTR(f_usb9pfs_opts_, buflen);
> +
> +static struct configfs_attribute *usb9pfs_attrs[] = {
> + &f_usb9pfs_opts_attr_buflen,
> + NULL,
> +};
> +
> +static const struct config_item_type usb9pfs_func_type = {
> + .ct_item_ops = &usb9pfs_item_ops,
> + .ct_attrs = usb9pfs_attrs,
> + .ct_owner = THIS_MODULE,
> +};
> +
> +static struct f_usb9pfs_dev *_usb9pfs_do_find_dev(const char *tag)
> +{
> + struct f_usb9pfs_dev *usb9pfs_dev;
> + struct f_usb9pfs_dev *tmp;
> +
> + if (!tag)
> + return NULL;
> +
> + list_for_each_entry_safe(usb9pfs_dev, tmp, &usbg_instance_list, usb9pfs_instance) {
> + if (strcmp(usb9pfs_dev->tag, tag) == 0)
> + return usb9pfs_dev;
> + }
> +
> + return NULL;
> +}
> +
> +static int usb9pfs_tag_instance(struct f_usb9pfs_dev *dev, const char *tag)
> +{
> + struct f_usb9pfs_dev *existing;
> + int ret = 0;
> +
> + mutex_lock(&usb9pfs_lock);
> + existing = _usb9pfs_do_find_dev(tag);
> + if (!existing)
> + strscpy(dev->tag, tag, ARRAY_SIZE(dev->tag));
> + else if (existing != dev)
> + ret = -EBUSY;
> + mutex_unlock(&usb9pfs_lock);
> +
> + return ret;
> +}
> +
> +static int usb9pfs_set_inst_tag(struct usb_function_instance *fi, const char *tag)
> +{
> + if (strlen(tag) >= sizeof_field(struct f_usb9pfs_dev, tag))
> + return -ENAMETOOLONG;
> + return usb9pfs_tag_instance(fi_to_f_usb9pfs_opts(fi)->dev, tag);
> +}
> +
> +static void usb9pfs_free_instance(struct usb_function_instance *fi)
> +{
> + struct f_usb9pfs_opts *usb9pfs_opts;
> +
> + usb9pfs_opts = container_of(fi, struct f_usb9pfs_opts, func_inst);
> + kfree(usb9pfs_opts);
> +}
> +
> +static struct usb_function_instance *usb9pfs_alloc_instance(void)
> +{
> + struct f_usb9pfs_opts *usb9pfs_opts;
> + struct f_usb9pfs_dev *dev;
> +
> + usb9pfs_opts = kzalloc(sizeof(*usb9pfs_opts), GFP_KERNEL);
> + if (!usb9pfs_opts)
> + return ERR_PTR(-ENOMEM);
> +
> + mutex_init(&usb9pfs_opts->lock);
> +
> + usb9pfs_opts->func_inst.set_inst_name = usb9pfs_set_inst_tag;
> + usb9pfs_opts->func_inst.free_func_inst = usb9pfs_free_instance;
> +
> + usb9pfs_opts->buflen = DEFAULT_BUFLEN;
> +
> + mutex_lock(&usb9pfs_lock);
> + dev = kzalloc(sizeof(*dev), GFP_KERNEL);
> + if (IS_ERR(dev)) {
> + mutex_unlock(&usb9pfs_lock);
> + kfree(usb9pfs_opts);
> + return ERR_CAST(dev);
> + }
> + list_add_tail(&dev->usb9pfs_instance, &usbg_instance_list);
> + mutex_unlock(&usb9pfs_lock);
> +
> + usb9pfs_opts->dev = dev;
> + dev->opts = usb9pfs_opts;
> +
> + config_group_init_type_name(&usb9pfs_opts->func_inst.group, "",
> + &usb9pfs_func_type);
> +
> + return &usb9pfs_opts->func_inst;
> +}
> +DECLARE_USB_FUNCTION(usb9pfs, usb9pfs_alloc_instance, usb9pfs_alloc);
> +
> +static int __init usb9pfs_modinit(void)
> +{
> + int ret;
> +
> + INIT_LIST_HEAD(&usbg_instance_list);
> +
> + ret = usb_function_register(&usb9pfsusb_func);
> + if (!ret)
> + v9fs_register_trans(&p9_usbg_trans);
> +
> + return ret;
> +}
> +
> +static void __exit usb9pfs_modexit(void)
> +{
> + usb_function_unregister(&usb9pfsusb_func);
> + v9fs_unregister_trans(&p9_usbg_trans);
> +}
> +
> +module_init(usb9pfs_modinit);
> +module_exit(usb9pfs_modexit);
> +
> +MODULE_ALIAS_9P("usbg");
> +MODULE_LICENSE("GPL");
> +MODULE_DESCRIPTION("USB gadget 9pfs transport");
> +MODULE_AUTHOR("Michael Grzeschik");
>