[PATCH] UHCI: Eliminate the TD-removal list

This patch (as682) gets rid of the TD-removal list in uhci-hcd.  It is
no longer needed because now TDs are not freed until we know the
hardware isn't using them.  It also simplifies the code for adding and
removing TDs to/from URBs.

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

3 files changed, 27 insertions, 71 deletions

diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index d225e11f4055..fb4c1a8cadf4 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -492,7 +492,6 @@ static int uhci_start(struct usb_hcd *hcd)
 
         spin_lock_init(&uhci->lock);
 
-        INIT_LIST_HEAD(&uhci->td_remove_list);
         INIT_LIST_HEAD(&uhci->idle_qh_list);
 
         init_waitqueue_head(&uhci->waitqh);
diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 3093ca250942..90ef7fbbf2fb 100644
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -228,7 +228,6 @@ struct uhci_td {
         dma_addr_t dma_handle;
 
         struct list_head list;
-        struct list_head remove_list;
 
         int frame;                      /* for iso: what frame? */
         struct list_head fl_list;
@@ -420,10 +419,6 @@ struct uhci_hcd {
         unsigned long resuming_ports;
         unsigned long ports_timeout;            /* Time to stop signalling */
 
-        /* List of TDs that are done, but waiting to be freed (race) */
-        struct list_head td_remove_list;
-        unsigned int td_remove_age;             /* Age in frames */
-
         struct list_head idle_qh_list;          /* Where the idle QHs live */
 
         int rh_numports;                        /* Number of root-hub ports */
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index 64b6c74789fd..12af6fb05a30 100644
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -16,7 +16,6 @@
  * (C) Copyright 2004-2005 Alan Stern, stern@rowland.harvard.edu
  */
 
-static void uhci_free_pending_tds(struct uhci_hcd *uhci);
 
 /*
  * Technically, updating td->status here is a race, but it's not really a
@@ -51,7 +50,6 @@ static struct uhci_td *uhci_alloc_td(struct uhci_hcd *uhci)
         td->frame = -1;
 
         INIT_LIST_HEAD(&td->list);
-        INIT_LIST_HEAD(&td->remove_list);
         INIT_LIST_HEAD(&td->fl_list);
 
         return td;
@@ -61,8 +59,6 @@ static void uhci_free_td(struct uhci_hcd *uhci, struct uhci_td *td)
 {
         if (!list_empty(&td->list))
                 dev_warn(uhci_dev(uhci), "td %p still in list!\n", td);
-        if (!list_empty(&td->remove_list))
-                dev_warn(uhci_dev(uhci), "td %p still in remove_list!\n", td);
         if (!list_empty(&td->fl_list))
                 dev_warn(uhci_dev(uhci), "td %p still in fl_list!\n", td);
 
@@ -77,6 +73,16 @@ static inline void uhci_fill_td(struct uhci_td *td, u32 status,
         td->buffer = cpu_to_le32(buffer);
 }
 
+static void uhci_add_td_to_urbp(struct uhci_td *td, struct urb_priv *urbp)
+{
+        list_add_tail(&td->list, &urbp->td_list);
+}
+
+static void uhci_remove_td_from_urbp(struct uhci_td *td)
+{
+        list_del_init(&td->list);
+}
+
 /*
  * We insert Isochronous URBs directly into the frame list at the beginning
  */
@@ -421,21 +427,6 @@ static inline struct urb_priv *uhci_alloc_urb_priv(struct uhci_hcd *uhci,
         return urbp;
 }
 
-static void uhci_add_td_to_urb(struct urb *urb, struct uhci_td *td)
-{
-        struct urb_priv *urbp = (struct urb_priv *)urb->hcpriv;
-
-        list_add_tail(&td->list, &urbp->td_list);
-}
-
-static void uhci_remove_td_from_urb(struct uhci_td *td)
-{
-        if (list_empty(&td->list))
-                return;
-
-        list_del_init(&td->list);
-}
-
 static void uhci_free_urb_priv(struct uhci_hcd *uhci,
                 struct urb_priv *urbp)
 {
@@ -445,20 +436,9 @@ static void uhci_free_urb_priv(struct uhci_hcd *uhci,
                 dev_warn(uhci_dev(uhci), "urb %p still on QH's list!\n",
                                 urbp->urb);
 
-        uhci_get_current_frame_number(uhci);
-        if (uhci->frame_number + uhci->is_stopped != uhci->td_remove_age) {
-                uhci_free_pending_tds(uhci);
-                uhci->td_remove_age = uhci->frame_number;
-        }
-
-        /* Check to see if the remove list is empty. Set the IOC bit */
-        /* to force an interrupt so we can remove the TDs. */
-        if (list_empty(&uhci->td_remove_list))
-                uhci_set_next_interrupt(uhci);
-
         list_for_each_entry_safe(td, tmp, &urbp->td_list, list) {
-                uhci_remove_td_from_urb(td);
-                list_add(&td->remove_list, &uhci->td_remove_list);
+                uhci_remove_td_from_urbp(td);
+                uhci_free_td(uhci, td);
         }
 
         urbp->urb->hcpriv = NULL;
@@ -529,6 +509,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
         int len = urb->transfer_buffer_length;
         dma_addr_t data = urb->transfer_dma;
         __le32 *plink;
+        struct urb_priv *urbp = urb->hcpriv;
 
         /* The "pipe" thing contains the destination in bits 8--18 */
         destination = (urb->pipe & PIPE_DEVEP_MASK) | USB_PID_SETUP;
@@ -542,7 +523,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
          * Build the TD for the control request setup packet
          */
         td = qh->dummy_td;
-        uhci_add_td_to_urb(urb, td);
+        uhci_add_td_to_urbp(td, urbp);
         uhci_fill_td(td, status, destination | uhci_explen(8),
                         urb->setup_dma);
         plink = &td->link;
@@ -574,7 +555,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
                 /* Alternate Data0/1 (start with Data1) */
                 destination ^= TD_TOKEN_TOGGLE;
         
-                uhci_add_td_to_urb(urb, td);
+                uhci_add_td_to_urbp(td, urbp);
                 uhci_fill_td(td, status, destination | uhci_explen(pktsze),
                                 data);
                 plink = &td->link;
@@ -605,7 +586,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
 
         status &= ~TD_CTRL_SPD;
 
-        uhci_add_td_to_urb(urb, td);
+        uhci_add_td_to_urbp(td, urbp);
         uhci_fill_td(td, status | TD_CTRL_IOC,
                         destination | uhci_explen(0), 0);
         plink = &td->link;
@@ -640,7 +621,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb,
 
 nomem:
         /* Remove the dummy TD from the td_list so it doesn't get freed */
-        uhci_remove_td_from_urb(qh->dummy_td);
+        uhci_remove_td_from_urbp(qh->dummy_td);
         return -ENOMEM;
 }
 
@@ -656,6 +637,7 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
         int len = urb->transfer_buffer_length;
         dma_addr_t data = urb->transfer_dma;
         __le32 *plink;
+        struct urb_priv *urbp = urb->hcpriv;
         unsigned int toggle;
 
         if (len < 0)
@@ -693,7 +675,7 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
                                 goto nomem;
                         *plink = cpu_to_le32(td->dma_handle);
                 }
-                uhci_add_td_to_urb(urb, td);
+                uhci_add_td_to_urbp(td, urbp);
                 uhci_fill_td(td, status,
                                 destination | uhci_explen(pktsze) |
                                         (toggle << TD_TOKEN_TOGGLE_SHIFT),
@@ -721,7 +703,7 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
                         goto nomem;
                 *plink = cpu_to_le32(td->dma_handle);
 
-                uhci_add_td_to_urb(urb, td);
+                uhci_add_td_to_urbp(td, urbp);
                 uhci_fill_td(td, status,
                                 destination | uhci_explen(0) |
                                         (toggle << TD_TOKEN_TOGGLE_SHIFT),
@@ -758,7 +740,7 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
 
 nomem:
         /* Remove the dummy TD from the td_list so it doesn't get freed */
-        uhci_remove_td_from_urb(qh->dummy_td);
+        uhci_remove_td_from_urbp(qh->dummy_td);
         return -ENOMEM;
 }
 
@@ -830,8 +812,8 @@ static int uhci_fixup_short_transfer(struct uhci_hcd *uhci,
                 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);
+                uhci_remove_td_from_urbp(td);
+                uhci_free_td(uhci, td);
         }
         return ret;
 }
@@ -885,10 +867,9 @@ static int uhci_result_common(struct uhci_hcd *uhci, struct urb *urb)
                                 ret = 1;
                 }
 
-                uhci_remove_td_from_urb(td);
+                uhci_remove_td_from_urbp(td);
                 if (qh->post_td)
-                        list_add(&qh->post_td->remove_list,
-                                        &uhci->td_remove_list);
+                        uhci_free_td(uhci, qh->post_td);
                 qh->post_td = td;
 
                 if (ret != 0)
@@ -957,7 +938,7 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
                 if (!td)
                         return -ENOMEM;
 
-                uhci_add_td_to_urb(urb, td);
+                uhci_add_td_to_urbp(td, urbp);
                 uhci_fill_td(td, status, destination |
                                 uhci_explen(urb->iso_frame_desc[i].length),
                                 urb->transfer_dma +
@@ -1267,17 +1248,6 @@ restart:
                 uhci_make_qh_idle(uhci, qh);
 }
 
-static void uhci_free_pending_tds(struct uhci_hcd *uhci)
-{
-        struct uhci_td *td, *tmp;
-
-        list_for_each_entry_safe(td, tmp, &uhci->td_remove_list, remove_list) {
-                list_del_init(&td->remove_list);
-
-                uhci_free_td(uhci, td);
-        }
-}
-
 /*
  * Process events in the schedule, but only in one thread at a time
  */
@@ -1298,9 +1268,6 @@ static void uhci_scan_schedule(struct uhci_hcd *uhci, struct pt_regs *regs)
         uhci_clear_next_interrupt(uhci);
         uhci_get_current_frame_number(uhci);
 
-        if (uhci->frame_number + uhci->is_stopped != uhci->td_remove_age)
-                uhci_free_pending_tds(uhci);
-
         /* Go through all the QH queues and process the URBs in each one */
         for (i = 0; i < UHCI_NUM_SKELQH - 1; ++i) {
                 uhci->next_qh = list_entry(uhci->skelqh[i]->node.next,
@@ -1316,12 +1283,7 @@ static void uhci_scan_schedule(struct uhci_hcd *uhci, struct pt_regs *regs)
                 goto rescan;
         uhci->scan_in_progress = 0;
 
-        /* If the controller is stopped, we can finish these off right now */
-        if (uhci->is_stopped)
-                uhci_free_pending_tds(uhci);
-
-        if (list_empty(&uhci->td_remove_list) &&
-                        list_empty(&uhci->skel_unlink_qh->node))
+        if (list_empty(&uhci->skel_unlink_qh->node))
                 uhci_clear_next_interrupt(uhci);
         else
                 uhci_set_next_interrupt(uhci);