USB: EHCI: don't refcount iso_stream structures

This patch (as1580) makes ehci_iso_stream structures behave more like
QHs, in that they will remain allocated until their isochronous
endpoint is disabled.  This will come in useful in the future, when
periodic bandwidth gets allocated as an altsetting is installed rather
than on-the-fly.

For now, the change to the ehci_iso_stream lifetimes means that each
structure is always deallocated at exactly one spot in
ehci_endpoint_disable() and never used again.  As a result, it is no
longer necessary to use reference counting on these things, and the
patch removes it.

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

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 98b945840c9e5bb2941bb032f5096b3248d1acea..fb1966cf56497c757e5f97e30e9bfd40d5dcd165 100644 (file)
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -1085,8 +1085,14 @@ rescan:
         * accelerate iso completions ... so spin a while.
         */
        if (qh->hw == NULL) {
-               ehci_vdbg (ehci, "iso delay\n");
-               goto idle_timeout;
+               struct ehci_iso_stream  *stream = ep->hcpriv;
+
+               if (!list_empty(&stream->td_list))
+                       goto idle_timeout;
+
+               /* BUG_ON(!list_empty(&stream->free_list)); */
+               kfree(stream);
+               goto done;
        }
 
        if (ehci->rh_state < EHCI_RH_RUNNING)
@@ -1127,8 +1133,8 @@ idle_timeout:
                        list_empty (&qh->qtd_list) ? "" : "(has tds)");
                break;
        }
+ done:
        ep->hcpriv = NULL;
-done:
        spin_unlock_irqrestore (&ehci->lock, flags);
 }
 

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 1e4f13c11b6a705f57f5eb3f72efe4c181d59712..11b2f21d7ac169ceedca9f2bdb80e493f3cfe416 100644 (file)
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -934,7 +934,6 @@ iso_stream_alloc (gfp_t mem_flags)
                INIT_LIST_HEAD(&stream->td_list);
                INIT_LIST_HEAD(&stream->free_list);
                stream->next_uframe = -1;
-               stream->refcount = 1;
        }
        return stream;
 }
@@ -1034,32 +1033,6 @@ iso_stream_init (
        stream->maxp = maxp;
 }
 
-static void
-iso_stream_put(struct ehci_hcd *ehci, struct ehci_iso_stream *stream)
-{
-       stream->refcount--;
-
-       /* free whenever just a dev->ep reference remains.
-        * not like a QH -- no persistent state (toggle, halt)
-        */
-       if (stream->refcount == 1) {
-               // BUG_ON (!list_empty(&stream->td_list));
-
-               if (stream->ep)
-                       stream->ep->hcpriv = NULL;
-
-               kfree(stream);
-       }
-}
-
-static inline struct ehci_iso_stream *
-iso_stream_get (struct ehci_iso_stream *stream)
-{
-       if (likely (stream != NULL))
-               stream->refcount++;
-       return stream;
-}
-
 static struct ehci_iso_stream *
 iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
 {
@@ -1080,7 +1053,6 @@ iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
        if (unlikely (stream == NULL)) {
                stream = iso_stream_alloc(GFP_ATOMIC);
                if (likely (stream != NULL)) {
-                       /* dev->ep owns the initial refcount */
                        ep->hcpriv = stream;
                        stream->ep = ep;
                        iso_stream_init(ehci, stream, urb->dev, urb->pipe,
@@ -1095,9 +1067,6 @@ iso_stream_find (struct ehci_hcd *ehci, struct urb *urb)
                stream = NULL;
        }
 
-       /* caller guarantees an eventual matching iso_stream_put */
-       stream = iso_stream_get (stream);
-
        spin_unlock_irqrestore (&ehci->lock, flags);
        return stream;
 }
@@ -1611,7 +1580,7 @@ static void itd_link_urb(
                        itd = list_entry (iso_sched->td_list.next,
                                        struct ehci_itd, itd_list);
                        list_move_tail (&itd->itd_list, &stream->td_list);
-                       itd->stream = iso_stream_get (stream);
+                       itd->stream = stream;
                        itd->urb = urb;
                        itd_init (ehci, stream, itd);
                }
@@ -1735,7 +1704,6 @@ itd_complete (
                        dev->devpath, stream->bEndpointAddress & 0x0f,
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
        }
-       iso_stream_put (ehci, stream);
 
 done:
        itd->urb = NULL;
@@ -1750,7 +1718,6 @@ done:
                start_free_itds(ehci);
        }
 
-       iso_stream_put(ehci, stream);
        return retval;
 }
 
@@ -1807,12 +1774,9 @@ static int itd_submit (struct ehci_hcd *ehci, struct urb *urb,
                itd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
        else
                usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
-done_not_linked:
+ done_not_linked:
        spin_unlock_irqrestore (&ehci->lock, flags);
-
-done:
-       if (unlikely (status < 0))
-               iso_stream_put (ehci, stream);
+ done:
        return status;
 }
 
@@ -2028,7 +1992,7 @@ static void sitd_link_urb(
                sitd = list_entry (sched->td_list.next,
                                struct ehci_sitd, sitd_list);
                list_move_tail (&sitd->sitd_list, &stream->td_list);
-               sitd->stream = iso_stream_get (stream);
+               sitd->stream = stream;
                sitd->urb = urb;
 
                sitd_patch(ehci, stream, sitd, sched, packet);
@@ -2126,7 +2090,6 @@ sitd_complete (
                        dev->devpath, stream->bEndpointAddress & 0x0f,
                        (stream->bEndpointAddress & USB_DIR_IN) ? "in" : "out");
        }
-       iso_stream_put (ehci, stream);
 
 done:
        sitd->urb = NULL;
@@ -2141,7 +2104,6 @@ done:
                start_free_itds(ehci);
        }
 
-       iso_stream_put(ehci, stream);
        return retval;
 }
 
@@ -2195,12 +2157,9 @@ static int sitd_submit (struct ehci_hcd *ehci, struct urb *urb,
                sitd_link_urb (ehci, urb, ehci->periodic_size << 3, stream);
        else
                usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb);
-done_not_linked:
+ done_not_linked:
        spin_unlock_irqrestore (&ehci->lock, flags);
-
-done:
-       if (status < 0)
-               iso_stream_put (ehci, stream);
+ done:
        return status;
 }
 

diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index bcfbb175e2b4b1c442e88878cba7ace47270a021..755e30b0000ba35b79bc25e9be200a947205ec2d 100644 (file)
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -386,7 +386,7 @@ struct ehci_qh_hw {
 } __attribute__ ((aligned(32)));
 
 struct ehci_qh {
-       struct ehci_qh_hw       *hw;
+       struct ehci_qh_hw       *hw;            /* Must come first */
        /* the rest is HCD-private */
        dma_addr_t              qh_dma;         /* address of qh */
        union ehci_shadow       qh_next;        /* ptr to qh; or periodic */
@@ -453,7 +453,6 @@ struct ehci_iso_stream {
        /* first field matches ehci_hq, but is NULL */
        struct ehci_qh_hw       *hw;
 
-       u32                     refcount;
        u8                      bEndpointAddress;
        u8                      highspeed;
        struct list_head        td_list;        /* queued itds/sitds */