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