drivers/usb/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                         continue;
  36
  37                 urb = priv->urb;
  38                 status = urb->status;
  39
  40                 usbip_dbg_vhci_rx("find urb seqnum %u\n", seqnum);
  41
  42                 switch (status) {
  43                 case -ENOENT:
  44                         /* fall through */
  45                 case -ECONNRESET:
  46                         dev_dbg(&urb->dev->dev,
  47                                  "urb seq# %u was unlinked %ssynchronuously\n",
  48                                  seqnum, status == -ENOENT ? "" : "a");
  49                         break;
  50                 case -EINPROGRESS:
  51                         /* no info output */
  52                         break;
  53                 default:
  54                         dev_dbg(&urb->dev->dev,
  55                                  "urb seq# %u may be in a error, status %d\n",
  56                                  seqnum, status);
  57                 }
  58
  59                 list_del(&priv->list);
  60                 kfree(priv);
  61                 urb->hcpriv = NULL;
  62
  63                 break;
  64         }
  65
  66         return urb;
  67 }
  68
  69 static void vhci_recv_ret_submit(struct vhci_device *vdev,
  70                                  struct usbip_header *pdu)
  71 {
  72         struct vhci_hcd *vhci = vdev_to_vhci(vdev);
  73         struct usbip_device *ud = &vdev->ud;
  74         struct urb *urb;
  75         unsigned long flags;
  76
  77         spin_lock_irqsave(&vdev->priv_lock, flags);
  78         urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
  79         spin_unlock_irqrestore(&vdev->priv_lock, flags);
  80
  81         if (!urb) {
  82                 pr_err("cannot find a urb of seqnum %u max seqnum %d\n",
  83                         pdu->base.seqnum,
  84                         atomic_read(&vhci->seqnum));
  85                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
  86                 return;
  87         }
  88
  89         /* unpack the pdu to a urb */
  90         usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
  91
  92         /* recv transfer buffer */
  93         if (usbip_recv_xbuff(ud, urb) < 0)
  94                 return;
  95
  96         /* recv iso_packet_descriptor */
  97         if (usbip_recv_iso(ud, urb) < 0)
  98                 return;
  99
 100         /* restore the padding in iso packets */
 101         usbip_pad_iso(ud, urb);
 102
 103         if (usbip_dbg_flag_vhci_rx)
 104                 usbip_dump_urb(urb);
 105
 106         usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
 107
 108         spin_lock_irqsave(&vhci->lock, flags);
 109         usb_hcd_unlink_urb_from_ep(vhci_to_hcd(vhci), urb);
 110         spin_unlock_irqrestore(&vhci->lock, flags);
 111
 112         usb_hcd_giveback_urb(vhci_to_hcd(vhci), urb, urb->status);
 113
 114         usbip_dbg_vhci_rx("Leave\n");
 115 }
 116
 117 static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
 118                                                   struct usbip_header *pdu)
 119 {
 120         struct vhci_unlink *unlink, *tmp;
 121         unsigned long flags;
 122
 123         spin_lock_irqsave(&vdev->priv_lock, flags);
 124
 125         list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
 126                 pr_info("unlink->seqnum %lu\n", unlink->seqnum);
 127                 if (unlink->seqnum == pdu->base.seqnum) {
 128                         usbip_dbg_vhci_rx("found pending unlink, %lu\n",
 129                                           unlink->seqnum);
 130                         list_del(&unlink->list);
 131
 132                         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 133                         return unlink;
 134                 }
 135         }
 136
 137         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 138
 139         return NULL;
 140 }
 141
 142 static void vhci_recv_ret_unlink(struct vhci_device *vdev,
 143                                  struct usbip_header *pdu)
 144 {
 145         struct vhci_hcd *vhci = vdev_to_vhci(vdev);
 146         struct vhci_unlink *unlink;
 147         struct urb *urb;
 148         unsigned long flags;
 149
 150         usbip_dump_header(pdu);
 151
 152         unlink = dequeue_pending_unlink(vdev, pdu);
 153         if (!unlink) {
 154                 pr_info("cannot find the pending unlink %u\n",
 155                         pdu->base.seqnum);
 156                 return;
 157         }
 158
 159         spin_lock_irqsave(&vdev->priv_lock, flags);
 160         urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
 161         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 162
 163         if (!urb) {
 164                 /*
 165                  * I get the result of a unlink request. But, it seems that I
 166                  * already received the result of its submit result and gave
 167                  * back the URB.
 168                  */
 169                 pr_info("the urb (seqnum %d) was already given back\n",
 170                         pdu->base.seqnum);
 171         } else {
 172                 usbip_dbg_vhci_rx("now giveback urb %d\n", pdu->base.seqnum);
 173
 174                 /* If unlink is successful, status is -ECONNRESET */
 175                 urb->status = pdu->u.ret_unlink.status;
 176                 pr_info("urb->status %d\n", urb->status);
 177
 178                 spin_lock_irqsave(&vhci->lock, flags);
 179                 usb_hcd_unlink_urb_from_ep(vhci_to_hcd(vhci), urb);
 180                 spin_unlock_irqrestore(&vhci->lock, flags);
 181
 182                 usb_hcd_giveback_urb(vhci_to_hcd(vhci), urb, urb->status);
 183         }
 184
 185         kfree(unlink);
 186 }
 187
 188 static int vhci_priv_tx_empty(struct vhci_device *vdev)
 189 {
 190         int empty = 0;
 191         unsigned long flags;
 192
 193         spin_lock_irqsave(&vdev->priv_lock, flags);
 194         empty = list_empty(&vdev->priv_rx);
 195         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 196
 197         return empty;
 198 }
 199
 200 /* recv a pdu */
 201 static void vhci_rx_pdu(struct usbip_device *ud)
 202 {
 203         int ret;
 204         struct usbip_header pdu;
 205         struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
 206
 207         usbip_dbg_vhci_rx("Enter\n");
 208
 209         memset(&pdu, 0, sizeof(pdu));
 210
 211         /* receive a pdu header */
 212         ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
 213         if (ret < 0) {
 214                 if (ret == -ECONNRESET)
 215                         pr_info("connection reset by peer\n");
 216                 else if (ret == -EAGAIN) {
 217                         /* ignore if connection was idle */
 218                         if (vhci_priv_tx_empty(vdev))
 219                                 return;
 220                         pr_info("connection timed out with pending urbs\n");
 221                 } else if (ret != -ERESTARTSYS)
 222                         pr_info("xmit failed %d\n", ret);
 223
 224                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 225                 return;
 226         }
 227         if (ret == 0) {
 228                 pr_info("connection closed");
 229                 usbip_event_add(ud, VDEV_EVENT_DOWN);
 230                 return;
 231         }
 232         if (ret != sizeof(pdu)) {
 233                 pr_err("received pdu size is %d, should be %d\n", ret,
 234                        (unsigned int)sizeof(pdu));
 235                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 236                 return;
 237         }
 238
 239         usbip_header_correct_endian(&pdu, 0);
 240
 241         if (usbip_dbg_flag_vhci_rx)
 242                 usbip_dump_header(&pdu);
 243
 244         switch (pdu.base.command) {
 245         case USBIP_RET_SUBMIT:
 246                 vhci_recv_ret_submit(vdev, &pdu);
 247                 break;
 248         case USBIP_RET_UNLINK:
 249                 vhci_recv_ret_unlink(vdev, &pdu);
 250                 break;
 251         default:
 252                 /* NOT REACHED */
 253                 pr_err("unknown pdu %u\n", pdu.base.command);
 254                 usbip_dump_header(&pdu);
 255                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 256                 break;
 257         }
 258 }
 259
 260 int vhci_rx_loop(void *data)
 261 {
 262         struct usbip_device *ud = data;
 263
 264         while (!kthread_should_stop()) {
 265                 if (usbip_event_happened(ud))
 266                         break;
 267
 268                 vhci_rx_pdu(ud);
 269         }
 270
 271         return 0;
 272 }