stub_tx.c

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/*
 * Copyright (C) 2003-2008 Takahiro Hirofuchi
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
 * USA.
 */

#include <linux/kthread.h>
#include <linux/socket.h>

#include "usbip_common.h"
#include "stub.h"

static void stub_free_priv_and_urb(struct stub_priv *priv)
{
    struct urb *urb = priv->urb;

    kfree(urb->setup_packet);
    kfree(urb->transfer_buffer);
    list_del(&priv->list);
    kmem_cache_free(stub_priv_cache, priv);
    usb_free_urb(urb);
}

/* be in spin_lock_irqsave(&sdev->priv_lock, flags) */
void stub_enqueue_ret_unlink(struct stub_device *sdev, __u32 seqnum,
                 __u32 status)
{
    struct stub_unlink *unlink;

    unlink = kzalloc(sizeof(struct stub_unlink), GFP_ATOMIC);
    if (!unlink) {
        dev_err(&sdev->interface->dev, "alloc stub_unlink\n");
        usbip_event_add(&sdev->ud, VDEV_EVENT_ERROR_MALLOC);
        return;
    }

    unlink->seqnum = seqnum;
    unlink->status = status;

    list_add_tail(&unlink->list, &sdev->unlink_tx);
}

void stub_complete(struct urb *urb)
{
    struct stub_priv *priv = (struct stub_priv *) urb->context;
    struct stub_device *sdev = priv->sdev;
    unsigned long flags;

    usbip_dbg_stub_tx("complete! status %d\n", urb->status);

    switch (urb->status) {
    case 0:
        /* OK */
        break;
    case -ENOENT:
        dev_info(&urb->dev->dev, "stopped by a call to usb_kill_urb() "
             "because of cleaning up a virtual connection\n");
        return;
    case -ECONNRESET:
        dev_info(&urb->dev->dev, "unlinked by a call to "
             "usb_unlink_urb()\n");
        break;
    case -EPIPE:
        dev_info(&urb->dev->dev, "endpoint %d is stalled\n",
             usb_pipeendpoint(urb->pipe));
        break;
    case -ESHUTDOWN:
        dev_info(&urb->dev->dev, "device removed?\n");
        break;
    default:
        dev_info(&urb->dev->dev, "urb completion with non-zero status "
             "%d\n", urb->status);
        break;
    }

    /* link a urb to the queue of tx. */
    spin_lock_irqsave(&sdev->priv_lock, flags);
    if (priv->unlinking) {
        stub_enqueue_ret_unlink(sdev, priv->seqnum, urb->status);
        stub_free_priv_and_urb(priv);
    } else {
        list_move_tail(&priv->list, &sdev->priv_tx);
    }
    spin_unlock_irqrestore(&sdev->priv_lock, flags);

    /* wake up tx_thread */
    wake_up(&sdev->tx_waitq);
}

static inline void setup_base_pdu(struct usbip_header_basic *base,
                  __u32 command, __u32 seqnum)
{
    base->command   = command;
    base->seqnum    = seqnum;
    base->devid = 0;
    base->ep    = 0;
    base->direction = 0;
}

static void setup_ret_submit_pdu(struct usbip_header *rpdu, struct urb *urb)
{
    struct stub_priv *priv = (struct stub_priv *) urb->context;

    setup_base_pdu(&rpdu->base, USBIP_RET_SUBMIT, priv->seqnum);
    usbip_pack_pdu(rpdu, urb, USBIP_RET_SUBMIT, 1);
}

static void setup_ret_unlink_pdu(struct usbip_header *rpdu,
                 struct stub_unlink *unlink)
{
    setup_base_pdu(&rpdu->base, USBIP_RET_UNLINK, unlink->seqnum);
    rpdu->u.ret_unlink.status = unlink->status;
}

static struct stub_priv *dequeue_from_priv_tx(struct stub_device *sdev)
{
    unsigned long flags;
    struct stub_priv *priv, *tmp;

    spin_lock_irqsave(&sdev->priv_lock, flags);

    list_for_each_entry_safe(priv, tmp, &sdev->priv_tx, list) {
        list_move_tail(&priv->list, &sdev->priv_free);
        spin_unlock_irqrestore(&sdev->priv_lock, flags);
        return priv;
    }

    spin_unlock_irqrestore(&sdev->priv_lock, flags);

    return NULL;
}

static int stub_send_ret_submit(struct stub_device *sdev)
{
    unsigned long flags;
    struct stub_priv *priv, *tmp;

    struct msghdr msg;
    size_t txsize;

    size_t total_size = 0;

    while ((priv = dequeue_from_priv_tx(sdev)) != NULL) {
        int ret;
        struct urb *urb = priv->urb;
        struct usbip_header pdu_header;
        void *iso_buffer = NULL;
        struct kvec *iov = NULL;
        int iovnum = 0;

        txsize = 0;
        memset(&pdu_header, 0, sizeof(pdu_header));
        memset(&msg, 0, sizeof(msg));

        if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS)
            iovnum = 2 + urb->number_of_packets;
        else
            iovnum = 2;

        iov = kzalloc(iovnum * sizeof(struct kvec), GFP_KERNEL);

        if (!iov) {
            usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_MALLOC);
            return -1;
        }

        iovnum = 0;

        /* 1. setup usbip_header */
        setup_ret_submit_pdu(&pdu_header, urb);
        usbip_dbg_stub_tx("setup txdata seqnum: %d urb: %p\n",
                  pdu_header.base.seqnum, urb);
        /*usbip_dump_header(pdu_header);*/
        usbip_header_correct_endian(&pdu_header, 1);

        iov[iovnum].iov_base = &pdu_header;
        iov[iovnum].iov_len  = sizeof(pdu_header);
        iovnum++;
        txsize += sizeof(pdu_header);

        /* 2. setup transfer buffer */
        if (usb_pipein(urb->pipe) &&
            usb_pipetype(urb->pipe) != PIPE_ISOCHRONOUS &&
            urb->actual_length > 0) {
            iov[iovnum].iov_base = urb->transfer_buffer;
            iov[iovnum].iov_len  = urb->actual_length;
            iovnum++;
            txsize += urb->actual_length;
        } else if (usb_pipein(urb->pipe) &&
               usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
            /*
             * For isochronous packets: actual length is the sum of
             * the actual length of the individual, packets, but as
             * the packet offsets are not changed there will be
             * padding between the packets. To optimally use the
             * bandwidth the padding is not transmitted.
             */

            int i;
            for (i = 0; i < urb->number_of_packets; i++) {
                iov[iovnum].iov_base = urb->transfer_buffer +
                    urb->iso_frame_desc[i].offset;
                iov[iovnum].iov_len =
                    urb->iso_frame_desc[i].actual_length;
                iovnum++;
                txsize += urb->iso_frame_desc[i].actual_length;
            }

            if (txsize != sizeof(pdu_header) + urb->actual_length) {
                dev_err(&sdev->interface->dev,
                    "actual length of urb %d does not "
                    "match iso packet sizes %zu\n",
                    urb->actual_length,
                    txsize-sizeof(pdu_header));
                kfree(iov);
                usbip_event_add(&sdev->ud,
                        SDEV_EVENT_ERROR_TCP);
               return -1;
            }
        }

        /* 3. setup iso_packet_descriptor */
        if (usb_pipetype(urb->pipe) == PIPE_ISOCHRONOUS) {
            ssize_t len = 0;

            iso_buffer = usbip_alloc_iso_desc_pdu(urb, &len);
            if (!iso_buffer) {
                usbip_event_add(&sdev->ud,
                        SDEV_EVENT_ERROR_MALLOC);
                kfree(iov);
                return -1;
            }

            iov[iovnum].iov_base = iso_buffer;
            iov[iovnum].iov_len  = len;
            txsize += len;
            iovnum++;
        }

        ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg,
                        iov,  iovnum, txsize);
        if (ret != txsize) {
            dev_err(&sdev->interface->dev,
                "sendmsg failed!, retval %d for %zd\n",
                ret, txsize);
            kfree(iov);
            kfree(iso_buffer);
            usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
            return -1;
        }

        kfree(iov);
        kfree(iso_buffer);

        total_size += txsize;
    }

    spin_lock_irqsave(&sdev->priv_lock, flags);
    list_for_each_entry_safe(priv, tmp, &sdev->priv_free, list) {
        stub_free_priv_and_urb(priv);
    }
    spin_unlock_irqrestore(&sdev->priv_lock, flags);

    return total_size;
}

static struct stub_unlink *dequeue_from_unlink_tx(struct stub_device *sdev)
{
    unsigned long flags;
    struct stub_unlink *unlink, *tmp;

    spin_lock_irqsave(&sdev->priv_lock, flags);

    list_for_each_entry_safe(unlink, tmp, &sdev->unlink_tx, list) {
        list_move_tail(&unlink->list, &sdev->unlink_free);
        spin_unlock_irqrestore(&sdev->priv_lock, flags);
        return unlink;
    }

    spin_unlock_irqrestore(&sdev->priv_lock, flags);

    return NULL;
}

static int stub_send_ret_unlink(struct stub_device *sdev)
{
    unsigned long flags;
    struct stub_unlink *unlink, *tmp;

    struct msghdr msg;
    struct kvec iov[1];
    size_t txsize;

    size_t total_size = 0;

    while ((unlink = dequeue_from_unlink_tx(sdev)) != NULL) {
        int ret;
        struct usbip_header pdu_header;

        txsize = 0;
        memset(&pdu_header, 0, sizeof(pdu_header));
        memset(&msg, 0, sizeof(msg));
        memset(&iov, 0, sizeof(iov));

        usbip_dbg_stub_tx("setup ret unlink %lu\n", unlink->seqnum);

        /* 1. setup usbip_header */
        setup_ret_unlink_pdu(&pdu_header, unlink);
        usbip_header_correct_endian(&pdu_header, 1);

        iov[0].iov_base = &pdu_header;
        iov[0].iov_len  = sizeof(pdu_header);
        txsize += sizeof(pdu_header);

        ret = kernel_sendmsg(sdev->ud.tcp_socket, &msg, iov,
                     1, txsize);
        if (ret != txsize) {
            dev_err(&sdev->interface->dev,
                "sendmsg failed!, retval %d for %zd\n",
                ret, txsize);
            usbip_event_add(&sdev->ud, SDEV_EVENT_ERROR_TCP);
            return -1;
        }

        usbip_dbg_stub_tx("send txdata\n");
        total_size += txsize;
    }

    spin_lock_irqsave(&sdev->priv_lock, flags);

    list_for_each_entry_safe(unlink, tmp, &sdev->unlink_free, list) {
        list_del(&unlink->list);
        kfree(unlink);
    }

    spin_unlock_irqrestore(&sdev->priv_lock, flags);

    return total_size;
}

int stub_tx_loop(void *data)
{
    struct usbip_device *ud = data;
    struct stub_device *sdev = container_of(ud, struct stub_device, ud);

    while (!kthread_should_stop()) {
        if (usbip_event_happened(ud))
            break;

        /*
         * send_ret_submit comes earlier than send_ret_unlink.  stub_rx
         * looks at only priv_init queue. If the completion of a URB is
         * earlier than the receive of CMD_UNLINK, priv is moved to
         * priv_tx queue and stub_rx does not find the target priv. In
         * this case, vhci_rx receives the result of the submit request
         * and then receives the result of the unlink request. The
         * result of the submit is given back to the usbcore as the
         * completion of the unlink request. The request of the
         * unlink is ignored. This is ok because a driver who calls
         * usb_unlink_urb() understands the unlink was too late by
         * getting the status of the given-backed URB which has the
         * status of usb_submit_urb().
         */
        if (stub_send_ret_submit(sdev) < 0)
            break;

        if (stub_send_ret_unlink(sdev) < 0)
            break;

        wait_event_interruptible(sdev->tx_waitq,
                     (!list_empty(&sdev->priv_tx) ||
                      !list_empty(&sdev->unlink_tx) ||
                      kthread_should_stop()));
    }

    return 0;
}