[PATCH] UHCI: Remove non-iso TDs as they are used

This patch (as680) frees non-isochronous TDs as they are used, rather
than all at once when an URB is complete.  Although not a terribly
important change in itself, it opens the door to a later enhancement
that will reduce storage requirements by allocating only a limited
number of TDs at any time for each endpoint queue.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 45 insertions, 39 deletions

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index 28c1c51ec475..6bbd33db9358 100644
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -119,6 +119,7 @@ static int uhci_show_urbp(struct urb_priv *urbp, char *buf, int len, int space)
         }
 
         out += sprintf(out, "%s%s", ptype, (urbp->fsbr ? " FSBR" : ""));
+        out += sprintf(out, " Actlen=%d", urbp->urb->actual_length);
 
         if (urbp->urb->status != -EINPROGRESS)
                 out += sprintf(out, " Status=%d", urbp->urb->status);
diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 8e5778650493..3093ca250942 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -129,6 +129,7 @@ struct uhci_qh {
         struct list_head queue;         /* Queue of urbps for this QH */
         struct uhci_qh *skel;           /* Skeleton for this QH */
         struct uhci_td *dummy_td;       /* Dummy TD to end the queue */
+        struct uhci_td *post_td;        /* Last TD completed */
 
         unsigned int unlink_frame;      /* When the QH was unlinked */
         int state;                      /* QH_STATE_xxx; see above */
@@ -136,7 +137,7 @@ struct uhci_qh {
 
         unsigned int initial_toggle:1;  /* Endpoint's current toggle value */
         unsigned int needs_fixup:1;     /* Must fix the TD toggle values */
-        unsigned int is_stopped:1;      /* Queue was stopped by an error */
+        unsigned int is_stopped:1;      /* Queue was stopped by error/unlink */
 } __attribute__((aligned(16)));
 
 /*
@@ -456,8 +457,6 @@ struct urb_priv {
         struct list_head td_list;
 
         unsigned fsbr : 1;              /* URB turned on FSBR */
-        unsigned short_transfer : 1;    /* URB got a short transfer, no
-                                         * need to rescan */
 };
 
 
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index 30e36031fe21..888938d78230 100644
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -161,6 +161,7 @@ static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci,
         if (!qh)
                 return NULL;
 
+        memset(qh, 0, sizeof(*qh));
         qh->dma_handle = dma_handle;
 
         qh->element = UHCI_PTR_TERM;
@@ -183,7 +184,6 @@ static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci,
 
         } else {                /* Skeleton QH */
                 qh->state = QH_STATE_ACTIVE;
-                qh->udev = NULL;
                 qh->type = -1;
         }
         return qh;
@@ -223,16 +223,10 @@ static void uhci_save_toggle(struct uhci_qh *qh, struct urb *urb)
                         qh->type == USB_ENDPOINT_XFER_INT))
                 return;
 
-        /* Find the first active TD; that's the device's toggle state */
-        list_for_each_entry(td, &urbp->td_list, list) {
-                if (td_status(td) & TD_CTRL_ACTIVE) {
-                        qh->needs_fixup = 1;
-                        qh->initial_toggle = uhci_toggle(td_token(td));
-                        return;
-                }
-        }
-
-        WARN_ON(1);
+        WARN_ON(list_empty(&urbp->td_list));
+        td = list_entry(urbp->td_list.next, struct uhci_td, list);
+        qh->needs_fixup = 1;
+        qh->initial_toggle = uhci_toggle(td_token(td));
 }
 
 /*
@@ -372,6 +366,12 @@ static void uhci_make_qh_idle(struct uhci_hcd *uhci, struct uhci_qh *qh)
         list_move(&qh->node, &uhci->idle_qh_list);
         qh->state = QH_STATE_IDLE;
 
+        /* Now that the QH is idle, its post_td isn't being used */
+        if (qh->post_td) {
+                uhci_free_td(uhci, qh->post_td);
+                qh->post_td = NULL;
+        }
+
         /* If anyone is waiting for a QH to become idle, wake them up */
         if (uhci->num_waiting)
                 wake_up_all(&uhci->waitqh);
@@ -610,6 +610,8 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
                 qh->skel = uhci->skel_fs_control_qh;
                 uhci_inc_fsbr(uhci, urb);
         }
+
+        urb->actual_length = -8;        /* Account for the SETUP packet */
         return 0;
 
 nomem:
@@ -767,34 +769,46 @@ static inline int uhci_submit_interrupt(struct uhci_hcd *uhci, struct urb *urb,
  * Fix up the data structures following a short transfer
  */
 static int uhci_fixup_short_transfer(struct uhci_hcd *uhci,
-                struct uhci_qh *qh, struct urb_priv *urbp,
-                struct uhci_td *short_td)
+                struct uhci_qh *qh, struct urb_priv *urbp)
 {
         struct uhci_td *td;
-        int ret = 0;
+        struct list_head *tmp;
+        int ret;
 
         td = list_entry(urbp->td_list.prev, struct uhci_td, list);
         if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
-                urbp->short_transfer = 1;
 
                 /* When a control transfer is short, we have to restart
                  * the queue at the status stage transaction, which is
                  * the last TD. */
+                WARN_ON(list_empty(&urbp->td_list));
                 qh->element = cpu_to_le32(td->dma_handle);
+                tmp = td->list.prev;
                 ret = -EINPROGRESS;
 
-        } else if (!urbp->short_transfer) {
-                urbp->short_transfer = 1;
+        } else {
 
                 /* When a bulk/interrupt transfer is short, we have to
                  * fix up the toggles of the following URBs on the queue
                  * before restarting the queue at the next URB. */
-                qh->initial_toggle = uhci_toggle(td_token(short_td)) ^ 1;
+                qh->initial_toggle = uhci_toggle(td_token(qh->post_td)) ^ 1;
                 uhci_fixup_toggles(qh, 1);
 
+                if (list_empty(&urbp->td_list))
+                        td = qh->post_td;
                 qh->element = td->link;
+                tmp = urbp->td_list.prev;
+                ret = 0;
         }
 
+        /* Remove all the TDs we skipped over, from tmp back to the start */
+        while (tmp != &urbp->td_list) {
+                td = list_entry(tmp, struct uhci_td, list);
+                tmp = tmp->prev;
+
+                uhci_remove_td_from_urb(td);
+                list_add(&td->remove_list, &uhci->td_remove_list);
+        }
         return ret;
 }
 
@@ -805,29 +819,14 @@ static int uhci_result_common(struct uhci_hcd *uhci, struct urb *urb)
 {
         struct urb_priv *urbp = urb->hcpriv;
         struct uhci_qh *qh = urbp->qh;
-        struct uhci_td *td;
-        struct list_head *tmp;
+        struct uhci_td *td, *tmp;
         unsigned status;
         int ret = 0;
 
-        tmp = urbp->td_list.next;
-
-        if (qh->type == USB_ENDPOINT_XFER_CONTROL) {
-                if (urbp->short_transfer)
-                        tmp = urbp->td_list.prev;
-                else
-                        urb->actual_length = -8;        /* SETUP packet */
-        } else
-                urb->actual_length = 0;
-
-
-        while (tmp != &urbp->td_list) {
+        list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {
                 unsigned int ctrlstat;
                 int len;
 
-                td = list_entry(tmp, struct uhci_td, list);
-                tmp = tmp->next;
-
                 ctrlstat = td_status(td);
                 status = uhci_status_bits(ctrlstat);
                 if (status & TD_CTRL_ACTIVE)
@@ -862,6 +861,12 @@ static int uhci_result_common(struct uhci_hcd *uhci, struct urb *urb)
                                 ret = 1;
                 }
 
+                uhci_remove_td_from_urb(td);
+                if (qh->post_td)
+                        list_add(&qh->post_td->remove_list,
+                                        &uhci->td_remove_list);
+                qh->post_td = td;
+
                 if (ret != 0)
                         goto err;
         }
@@ -882,7 +887,7 @@ err:
                                 (ret == -EREMOTEIO);
 
         } else          /* Short packet received */
-                ret = uhci_fixup_short_transfer(uhci, qh, urbp, td);
+                ret = uhci_fixup_short_transfer(uhci, qh, urbp);
         return ret;
 }
 
@@ -1123,6 +1128,7 @@ __acquires(uhci->lock)
                 struct uhci_td *ptd, *ltd;
 
                 purbp = list_entry(urbp->node.prev, struct urb_priv, node);
+                WARN_ON(list_empty(&purbp->td_list));
                 ptd = list_entry(purbp->td_list.prev, struct uhci_td,
                                 list);
                 ltd = list_entry(urbp->td_list.prev, struct uhci_td,