drivers/usb/usbip/vhci_rx.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2003-2008 Takahiro Hirofuchi
   4  */
   5
   6 #include <linux/kthread.h>
   7 #include <linux/slab.h>
   8
   9 #include "usbip_common.h"
  10 #include "vhci.h"
  11
  12 /* get URB from transmitted urb queue. caller must hold vdev->priv_lock */
  13 struct urb *pickup_urb_and_free_priv(struct vhci_device *vdev, __u32 seqnum)
  14 {
  15         struct vhci_priv *priv, *tmp;
  16         struct urb *urb = NULL;
  17         int status;
  18
  19         list_for_each_entry_safe(priv, tmp, &vdev->priv_rx, list) {
  20                 if (priv->seqnum != seqnum)
  21                         continue;
  22
  23                 urb = priv->urb;
  24                 status = urb->status;
  25
  26                 usbip_dbg_vhci_rx("find urb %p vurb %p seqnum %u\n",
  27                                 urb, priv, seqnum);
  28
  29                 switch (status) {
  30                 case -ENOENT:
  31                         /* fall through */
  32                 case -ECONNRESET:
  33                         dev_info(&urb->dev->dev,
  34                                  "urb %p was unlinked %ssynchronuously.\n", urb,
  35                                  status == -ENOENT ? "" : "a");
  36                         break;
  37                 case -EINPROGRESS:
  38                         /* no info output */
  39                         break;
  40                 default:
  41                         dev_info(&urb->dev->dev,
  42                                  "urb %p may be in a error, status %d\n", urb,
  43                                  status);
  44                 }
  45
  46                 list_del(&priv->list);
  47                 kfree(priv);
  48                 urb->hcpriv = NULL;
  49
  50                 break;
  51         }
  52
  53         return urb;
  54 }
  55
  56 static void vhci_recv_ret_submit(struct vhci_device *vdev,
  57                                  struct usbip_header *pdu)
  58 {
  59         struct vhci_hcd *vhci_hcd = vdev_to_vhci_hcd(vdev);
  60         struct vhci *vhci = vhci_hcd->vhci;
  61         struct usbip_device *ud = &vdev->ud;
  62         struct urb *urb;
  63         unsigned long flags;
  64
  65         spin_lock_irqsave(&vdev->priv_lock, flags);
  66         urb = pickup_urb_and_free_priv(vdev, pdu->base.seqnum);
  67         spin_unlock_irqrestore(&vdev->priv_lock, flags);
  68
  69         if (!urb) {
  70                 pr_err("cannot find a urb of seqnum %u\n", pdu->base.seqnum);
  71                 pr_info("max seqnum %d\n",
  72                         atomic_read(&vhci_hcd->seqnum));
  73                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
  74                 return;
  75         }
  76
  77         /* unpack the pdu to a urb */
  78         usbip_pack_pdu(pdu, urb, USBIP_RET_SUBMIT, 0);
  79
  80         /* recv transfer buffer */
  81         if (usbip_recv_xbuff(ud, urb) < 0)
  82                 return;
  83
  84         /* recv iso_packet_descriptor */
  85         if (usbip_recv_iso(ud, urb) < 0)
  86                 return;
  87
  88         /* restore the padding in iso packets */
  89         usbip_pad_iso(ud, urb);
  90
  91         if (usbip_dbg_flag_vhci_rx)
  92                 usbip_dump_urb(urb);
  93
  94         usbip_dbg_vhci_rx("now giveback urb %p\n", urb);
  95
  96         spin_lock_irqsave(&vhci->lock, flags);
  97         usb_hcd_unlink_urb_from_ep(vhci_hcd_to_hcd(vhci_hcd), urb);
  98         spin_unlock_irqrestore(&vhci->lock, flags);
  99
 100         usb_hcd_giveback_urb(vhci_hcd_to_hcd(vhci_hcd), urb, urb->status);
 101
 102         usbip_dbg_vhci_rx("Leave\n");
 103 }
 104
 105 static struct vhci_unlink *dequeue_pending_unlink(struct vhci_device *vdev,
 106                                                   struct usbip_header *pdu)
 107 {
 108         struct vhci_unlink *unlink, *tmp;
 109         unsigned long flags;
 110
 111         spin_lock_irqsave(&vdev->priv_lock, flags);
 112
 113         list_for_each_entry_safe(unlink, tmp, &vdev->unlink_rx, list) {
 114                 pr_info("unlink->seqnum %lu\n", unlink->seqnum);
 115                 if (unlink->seqnum == pdu->base.seqnum) {
 116                         usbip_dbg_vhci_rx("found pending unlink, %lu\n",
 117                                           unlink->seqnum);
 118                         list_del(&unlink->list);
 119
 120                         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 121                         return unlink;
 122                 }
 123         }
 124
 125         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 126
 127         return NULL;
 128 }
 129
 130 static void vhci_recv_ret_unlink(struct vhci_device *vdev,
 131                                  struct usbip_header *pdu)
 132 {
 133         struct vhci_hcd *vhci_hcd = vdev_to_vhci_hcd(vdev);
 134         struct vhci *vhci = vhci_hcd->vhci;
 135         struct vhci_unlink *unlink;
 136         struct urb *urb;
 137         unsigned long flags;
 138
 139         usbip_dump_header(pdu);
 140
 141         unlink = dequeue_pending_unlink(vdev, pdu);
 142         if (!unlink) {
 143                 pr_info("cannot find the pending unlink %u\n",
 144                         pdu->base.seqnum);
 145                 return;
 146         }
 147
 148         spin_lock_irqsave(&vdev->priv_lock, flags);
 149         urb = pickup_urb_and_free_priv(vdev, unlink->unlink_seqnum);
 150         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 151
 152         if (!urb) {
 153                 /*
 154                  * I get the result of a unlink request. But, it seems that I
 155                  * already received the result of its submit result and gave
 156                  * back the URB.
 157                  */
 158                 pr_info("the urb (seqnum %d) was already given back\n",
 159                         pdu->base.seqnum);
 160         } else {
 161                 usbip_dbg_vhci_rx("now giveback urb %p\n", urb);
 162
 163                 /* If unlink is successful, status is -ECONNRESET */
 164                 urb->status = pdu->u.ret_unlink.status;
 165                 pr_info("urb->status %d\n", urb->status);
 166
 167                 spin_lock_irqsave(&vhci->lock, flags);
 168                 usb_hcd_unlink_urb_from_ep(vhci_hcd_to_hcd(vhci_hcd), urb);
 169                 spin_unlock_irqrestore(&vhci->lock, flags);
 170
 171                 usb_hcd_giveback_urb(vhci_hcd_to_hcd(vhci_hcd), urb, urb->status);
 172         }
 173
 174         kfree(unlink);
 175 }
 176
 177 static int vhci_priv_tx_empty(struct vhci_device *vdev)
 178 {
 179         int empty = 0;
 180         unsigned long flags;
 181
 182         spin_lock_irqsave(&vdev->priv_lock, flags);
 183         empty = list_empty(&vdev->priv_rx);
 184         spin_unlock_irqrestore(&vdev->priv_lock, flags);
 185
 186         return empty;
 187 }
 188
 189 /* recv a pdu */
 190 static void vhci_rx_pdu(struct usbip_device *ud)
 191 {
 192         int ret;
 193         struct usbip_header pdu;
 194         struct vhci_device *vdev = container_of(ud, struct vhci_device, ud);
 195
 196         usbip_dbg_vhci_rx("Enter\n");
 197
 198         memset(&pdu, 0, sizeof(pdu));
 199
 200         /* receive a pdu header */
 201         ret = usbip_recv(ud->tcp_socket, &pdu, sizeof(pdu));
 202         if (ret < 0) {
 203                 if (ret == -ECONNRESET)
 204                         pr_info("connection reset by peer\n");
 205                 else if (ret == -EAGAIN) {
 206                         /* ignore if connection was idle */
 207                         if (vhci_priv_tx_empty(vdev))
 208                                 return;
 209                         pr_info("connection timed out with pending urbs\n");
 210                 } else if (ret != -ERESTARTSYS)
 211                         pr_info("xmit failed %d\n", ret);
 212
 213                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 214                 return;
 215         }
 216         if (ret == 0) {
 217                 pr_info("connection closed");
 218                 usbip_event_add(ud, VDEV_EVENT_DOWN);
 219                 return;
 220         }
 221         if (ret != sizeof(pdu)) {
 222                 pr_err("received pdu size is %d, should be %d\n", ret,
 223                        (unsigned int)sizeof(pdu));
 224                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 225                 return;
 226         }
 227
 228         usbip_header_correct_endian(&pdu, 0);
 229
 230         if (usbip_dbg_flag_vhci_rx)
 231                 usbip_dump_header(&pdu);
 232
 233         switch (pdu.base.command) {
 234         case USBIP_RET_SUBMIT:
 235                 vhci_recv_ret_submit(vdev, &pdu);
 236                 break;
 237         case USBIP_RET_UNLINK:
 238                 vhci_recv_ret_unlink(vdev, &pdu);
 239                 break;
 240         default:
 241                 /* NOT REACHED */
 242                 pr_err("unknown pdu %u\n", pdu.base.command);
 243                 usbip_dump_header(&pdu);
 244                 usbip_event_add(ud, VDEV_EVENT_ERROR_TCP);
 245                 break;
 246         }
 247 }
 248
 249 int vhci_rx_loop(void *data)
 250 {
 251         struct usbip_device *ud = data;
 252
 253         while (!kthread_should_stop()) {
 254                 if (usbip_event_happened(ud))
 255                         break;
 256
 257                 vhci_rx_pdu(ud);
 258         }
 259
 260         return 0;
 261 }