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 usbip_device *ud = &vdev->ud;
  73         struct urb *urb;
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(&vdev->priv_lock, flags);
  77         urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
  78         spin_unlock_irqrestore(&vdev->priv_lock, flags);
  79
  80         if (!urb) {
  81                 pr_err("cannot find a urb of seqnum %u max seqnum %d\n",
  82                         pdu->base.seqnum,
  83                         atomic_read(&the_controller->seqnum));
  84                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
  85                 return;
  86         }
  87
  88         /* unpack the pdu to a urb */
  89         usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
  90
  91         /* recv transfer buffer */
  92         if (usbip_recv_xbuff(ud, urb) < 0)
  93                 return;
  94
  95         /* recv iso_packet_descriptor */
  96         if (usbip_recv_iso(ud, urb) < 0)
  97                 return;
  98
  99         /* restore the padding in iso packets */
 100         usbip_pad_iso(ud, urb);
 101
 102         if (usbip_dbg_flag_vhci_rx)
 103                 usbip_dump_urb(urb);
 104
 105         usbip_dbg_vhci_rx("now giveback urb %u\n", pdu->base.seqnum);
 106
 107         spin_lock_irqsave(&the_controller->lock, flags);
 108         usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
 109         spin_unlock_irqrestore(&the_controller->lock, flags);
 110
 111         usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb, urb->status);
 112
 113         usbip_dbg_vhci_rx("Leave\n");
 114 }
 115
 116 static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
 117                                                   struct usbip_header *pdu)
 118 {
 119         struct vhci_unlink *unlink, *tmp;
 120         unsigned long flags;
 121
 122         spin_lock_irqsave(&vdev->priv_lock, flags);
 123
 124         list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
 125                 pr_info("unlink->seqnum %lu\n", unlink->seqnum);
 126                 if (unlink->seqnum == pdu->base.seqnum) {
 127                         usbip_dbg_vhci_rx("found pending unlink, %lu\n",
 128                                           unlink->seqnum);
 129                         list_del(&unlink->list);
 130
 131                         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 132                         return unlink;
 133                 }
 134         }
 135
 136         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 137
 138         return NULL;
 139 }
 140
 141 static void vhci_recv_ret_unlink(struct vhci_device *vdev,
 142                                  struct usbip_header *pdu)
 143 {
 144         struct vhci_unlink *unlink;
 145         struct urb *urb;
 146         unsigned long flags;
 147
 148         usbip_dump_header(pdu);
 149
 150         unlink = dequeue_pending_unlink(vdev, pdu);
 151         if (!unlink) {
 152                 pr_info("cannot find the pending unlink %u\n",
 153                         pdu->base.seqnum);
 154                 return;
 155         }
 156
 157         spin_lock_irqsave(&vdev->priv_lock, flags);
 158         urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
 159         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 160
 161         if (!urb) {
 162                 /*
 163                  * I get the result of a unlink request. But, it seems that I
 164                  * already received the result of its submit result and gave
 165                  * back the URB.
 166                  */
 167                 pr_info("the urb (seqnum %d) was already given back\n",
 168                         pdu->base.seqnum);
 169         } else {
 170                 usbip_dbg_vhci_rx("now giveback urb %d\n", pdu->base.seqnum);
 171
 172                 /* If unlink is successful, status is -ECONNRESET */
 173                 urb->status = pdu->u.ret_unlink.status;
 174                 pr_info("urb->status %d\n", urb->status);
 175
 176                 spin_lock_irqsave(&the_controller->lock, flags);
 177                 usb_hcd_unlink_urb_from_ep(vhci_to_hcd(the_controller), urb);
 178                 spin_unlock_irqrestore(&the_controller->lock, flags);
 179
 180                 usb_hcd_giveback_urb(vhci_to_hcd(the_controller), urb,
 181                                      urb->status);
 182         }
 183
 184         kfree(unlink);
 185 }
 186
 187 static int vhci_priv_tx_empty(struct vhci_device *vdev)
 188 {
 189         int empty = 0;
 190         unsigned long flags;
 191
 192         spin_lock_irqsave(&vdev->priv_lock, flags);
 193         empty = list_empty(&vdev->priv_rx);
 194         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 195
 196         return empty;
 197 }
 198
 199 /* recv a pdu */
 200 static void vhci_rx_pdu(struct usbip_device *ud)
 201 {
 202         int ret;
 203         struct usbip_header pdu;
 204         struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
 205
 206         usbip_dbg_vhci_rx("Enter\n");
 207
 208         memset(&pdu, 0, sizeof(pdu));
 209
 210         /* receive a pdu header */
 211         ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
 212         if (ret < 0) {
 213                 if (ret == -ECONNRESET)
 214                         pr_info("connection reset by peer\n");
 215                 else if (ret == -EAGAIN) {
 216                         /* ignore if connection was idle */
 217                         if (vhci_priv_tx_empty(vdev))
 218                                 return;
 219                         pr_info("connection timed out with pending urbs\n");
 220                 } else if (ret != -ERESTARTSYS)
 221                         pr_info("xmit failed %d\n", ret);
 222
 223                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 224                 return;
 225         }
 226         if (ret == 0) {
 227                 pr_info("connection closed");
 228                 usbip_event_add(ud, VDEV_EVENT_DOWN);
 229                 return;
 230         }
 231         if (ret != sizeof(pdu)) {
 232                 pr_err("received pdu size is %d, should be %d\n", ret,
 233                        (unsigned int)sizeof(pdu));
 234                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 235                 return;
 236         }
 237
 238         usbip_header_correct_endian(&pdu, 0);
 239
 240         if (usbip_dbg_flag_vhci_rx)
 241                 usbip_dump_header(&pdu);
 242
 243         switch (pdu.base.command) {
 244         case USBIP_RET_SUBMIT:
 245                 vhci_recv_ret_submit(vdev, &pdu);
 246                 break;
 247         case USBIP_RET_UNLINK:
 248                 vhci_recv_ret_unlink(vdev, &pdu);
 249                 break;
 250         default:
 251                 /* NOT REACHED */
 252                 pr_err("unknown pdu %u\n", pdu.base.command);
 253                 usbip_dump_header(&pdu);
 254                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 255                 break;
 256         }
 257 }
 258
 259 int vhci_rx_loop(void *data)
 260 {
 261         struct usbip_device *ud = data;
 262
 263         while (!kthread_should_stop()) {
 264                 if (usbip_event_happened(ud))
 265                         break;
 266
 267                 vhci_rx_pdu(ud);
 268         }
 269
 270         return 0;
 271 }