drivers/staging/usbip/vhci_rx.c

   1 /*
   2  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   3  *
   4  * This is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  17  * USA.
  18  */
  19
  20 #include <linux/kthread.h>
  21 #include <linux/slab.h>
  22
  23 #include "usbip_common.h"
  24 #include "vhci.h"
  25
  26 /* get URB from transmitted urb queue. caller must hold vdev->priv_lock */
  27 struct urb *pickup_urb_and_free_priv(struct vhci_device *vdev, __u32 seqnum)
  28 {
  29         struct vhci_priv *priv, *tmp;
  30         struct urb *urb = NULL;
  31         int status;
  32
  33         list_for_each_entry_safe(priv, tmp, &vdev->priv_rx, list) {
  34                 if (priv->seqnum == seqnum) {
  35                         urb = priv->urb;
  36                         status = urb->status;
  37
  38                         usbip_dbg_vhci_rx("find urb seqnum %u\n", seqnum);
  39
  40                         /* TODO: fix logic here to improve indent situtation */
  41                         if (status != -EINPROGRESS) {
  42                                 if (status == -ENOENT ||
  43                                     status == -ECONNRESET)
  44                                         dev_dbg(&urb->dev->dev,
  45                                                 "urb seq# %u was unlinked %ssynchronuously\n",
  46                                                 seqnum, status == -ENOENT ? "" : "a");
  47                                 else
  48                                         dev_dbg(&urb->dev->dev,
  49                                                 "urb seq# %u may be in a error, status %d\n",
  50                                                 seqnum, status);
  51                         }
  52
  53                         list_del(&priv->list);
  54                         kfree(priv);
  55                         urb->hcpriv = NULL;
  56
  57                         break;
  58                 }
  59         }
  60
  61         return urb;
  62 }
  63
  64 static void vhci_recv_ret_submit(struct vhci_device *vdev,
  65                                  struct usbip_header *pdu)
  66 {
  67         struct usbip_device *ud = &vdev->ud;
  68         struct urb *urb;
  69         unsigned long flags;
  70
  71         spin_lock(&vdev->priv_lock);
  72         urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
  73         spin_unlock(&vdev->priv_lock);
  74
  75         if (!urb) {
  76                 pr_err("cannot find a urb of seqnum %u max seqnum %d\n",
  77                         pdu->base.seqnum,
  78                         atomic_read(&the_controller->seqnum));
  79                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
  80                 return;
  81         }
  82
  83         /* unpack the pdu to a urb */
  84         usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
  85
  86         /* recv transfer buffer */
  87         if (usbip_recv_xbuff(ud, urb) < 0)
  88                 return;
  89
  90         /* recv iso_packet_descriptor */
  91         if (usbip_recv_iso(ud, urb) < 0)
  92                 return;
  93
  94         /* restore the padding in iso packets */
  95         usbip_pad_iso(ud, urb);
  96
  97         if (usbip_dbg_flag_vhci_rx)
  98                 usbip_dump_urb(urb);
  99
 100         usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
 101
 102         spin_lock_irqsave(&the_controller->lock, flags);
 103         usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
 104         spin_unlock_irqrestore(&the_controller->lock, flags);
 105
 106         usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb, urb->status);
 107
 108         usbip_dbg_vhci_rx("Leave\n");
 109
 110         return;
 111 }
 112
 113 static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
 114                                                   struct usbip_header *pdu)
 115 {
 116         struct vhci_unlink *unlink, *tmp;
 117
 118         spin_lock(&vdev->priv_lock);
 119
 120         list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
 121                 pr_info("unlink->seqnum %lu\n", unlink->seqnum);
 122                 if (unlink->seqnum == pdu->base.seqnum) {
 123                         usbip_dbg_vhci_rx("found pending unlink, %lu\n",
 124                                           unlink->seqnum);
 125                         list_del(&unlink->list);
 126
 127                         spin_unlock(&vdev->priv_lock);
 128                         return unlink;
 129                 }
 130         }
 131
 132         spin_unlock(&vdev->priv_lock);
 133
 134         return NULL;
 135 }
 136
 137 static void vhci_recv_ret_unlink(struct vhci_device *vdev,
 138                                  struct usbip_header *pdu)
 139 {
 140         struct vhci_unlink *unlink;
 141         struct urb *urb;
 142         unsigned long flags;
 143
 144         usbip_dump_header(pdu);
 145
 146         unlink = dequeue_pending_unlink(vdev, pdu);
 147         if (!unlink) {
 148                 pr_info("cannot find the pending unlink %u\n",
 149                         pdu->base.seqnum);
 150                 return;
 151         }
 152
 153         spin_lock(&vdev->priv_lock);
 154         urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
 155         spin_unlock(&vdev->priv_lock);
 156
 157         if (!urb) {
 158                 /*
 159                  * I get the result of a unlink request. But, it seems that I
 160                  * already received the result of its submit result and gave
 161                  * back the URB.
 162                  */
 163                 pr_info("the urb (seqnum %d) was already given backed\n",
 164                         pdu->base.seqnum);
 165         } else {
 166                 usbip_dbg_vhci_rx("now giveback urb %d\n", pdu->base.seqnum);
 167
 168                 /* If unlink is succeed, status is -ECONNRESET */
 169                 urb->status = pdu->u.ret_unlink.status;
 170                 pr_info("urb->status %d\n", urb->status);
 171
 172                 spin_lock_irqsave(&the_controller->lock, flags);
 173                 usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
 174                 spin_unlock_irqrestore(&the_controller->lock, flags);
 175
 176                 usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
 177                                      urb->status);
 178         }
 179
 180         kfree(unlink);
 181 }
 182
 183 static int vhci_priv_tx_empty(struct vhci_device *vdev)
 184 {
 185         int empty = 0;
 186
 187         spin_lock(&vdev->priv_lock);
 188         empty = list_empty(&vdev->priv_rx);
 189         spin_unlock(&vdev->priv_lock);
 190
 191         return empty;
 192 }
 193
 194 /* recv a pdu */
 195 static void vhci_rx_pdu(struct usbip_device *ud)
 196 {
 197         int ret;
 198         struct usbip_header pdu;
 199         struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
 200
 201         usbip_dbg_vhci_rx("Enter\n");
 202
 203         memset(&pdu, 0, sizeof(pdu));
 204
 205         /* 1. receive a pdu header */
 206         ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
 207         if (ret < 0) {
 208                 if (ret == -ECONNRESET)
 209                         pr_info("connection reset by peer\n");
 210                 else if (ret == -EAGAIN) {
 211                         /* ignore if connection was idle */
 212                         if (vhci_priv_tx_empty(vdev))
 213                                 return;
 214                         pr_info("connection timed out with pending urbs\n");
 215                 } else if (ret != -ERESTARTSYS)
 216                         pr_info("xmit failed %d\n", ret);
 217
 218                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 219                 return;
 220         }
 221         if (ret == 0) {
 222                 pr_info("connection closed");
 223                 usbip_event_add(ud, VDEV_EVENT_DOWN);
 224                 return;
 225         }
 226         if (ret != sizeof(pdu)) {
 227                 pr_err("received pdu size is %d, should be %d\n", ret,
 228                        (unsigned int)sizeof(pdu));
 229                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 230                 return;
 231         }
 232
 233         usbip_header_correct_endian(&pdu, 0);
 234
 235         if (usbip_dbg_flag_vhci_rx)
 236                 usbip_dump_header(&pdu);
 237
 238         switch (pdu.base.command) {
 239         case USBIP_RET_SUBMIT:
 240                 vhci_recv_ret_submit(vdev, &pdu);
 241                 break;
 242         case USBIP_RET_UNLINK:
 243                 vhci_recv_ret_unlink(vdev, &pdu);
 244                 break;
 245         default:
 246                 /* NOT REACHED */
 247                 pr_err("unknown pdu %u\n", pdu.base.command);
 248                 usbip_dump_header(&pdu);
 249                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 250                 break;
 251         }
 252 }
 253
 254 int vhci_rx_loop(void *data)
 255 {
 256         struct usbip_device *ud = data;
 257
 258         while (!kthread_should_stop()) {
 259                 if (usbip_event_happened(ud))
 260                         break;
 261
 262                 vhci_rx_pdu(ud);
 263         }
 264
 265         return 0;
 266 }