From c83e1a9ff68a6535b81c40dc8fda99348ab480fb Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 11 Jul 2012 11:21:25 -0400 Subject: USB: EHCI: don't refcount QHs This patch (as1567) removes ehci-hcd's reference counting of QH structures. It's not necessary to refcount these things because they always get deallocated at exactly one spot in ehci_endpoint_disable() (except for two special QHs, ehci->async and ehci->dummy) and are never used again. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 2 +- drivers/usb/host/ehci-mem.c | 24 +++--------------------- drivers/usb/host/ehci-q.c | 12 +++--------- drivers/usb/host/ehci-sched.c | 5 +---- drivers/usb/host/ehci.h | 9 --------- 5 files changed, 8 insertions(+), 44 deletions(-) (limited to 'drivers/usb') diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index ab7306de8d16..1f8f792eec86 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -1179,7 +1179,7 @@ idle_timeout: if (qh->clearing_tt) goto idle_timeout; if (list_empty (&qh->qtd_list)) { - qh_put (qh); + qh_destroy(ehci, qh); break; } /* else FALL THROUGH */ diff --git a/drivers/usb/host/ehci-mem.c b/drivers/usb/host/ehci-mem.c index 12f70c302b0b..93132d8ad360 100644 --- a/drivers/usb/host/ehci-mem.c +++ b/drivers/usb/host/ehci-mem.c @@ -64,10 +64,8 @@ static inline void ehci_qtd_free (struct ehci_hcd *ehci, struct ehci_qtd *qtd) } -static void qh_destroy(struct ehci_qh *qh) +static void qh_destroy(struct ehci_hcd *ehci, struct ehci_qh *qh) { - struct ehci_hcd *ehci = qh->ehci; - /* clean qtds first, and know this is not linked */ if (!list_empty (&qh->qtd_list) || qh->qh_next.ptr) { ehci_dbg (ehci, "unused qh not empty!\n"); @@ -92,8 +90,6 @@ static struct ehci_qh *ehci_qh_alloc (struct ehci_hcd *ehci, gfp_t flags) if (!qh->hw) goto fail; memset(qh->hw, 0, sizeof *qh->hw); - qh->refcount = 1; - qh->ehci = ehci; qh->qh_dma = dma; // INIT_LIST_HEAD (&qh->qh_list); INIT_LIST_HEAD (&qh->qtd_list); @@ -113,20 +109,6 @@ fail: return NULL; } -/* to share a qh (cpu threads, or hc) */ -static inline struct ehci_qh *qh_get (struct ehci_qh *qh) -{ - WARN_ON(!qh->refcount); - qh->refcount++; - return qh; -} - -static inline void qh_put (struct ehci_qh *qh) -{ - if (!--qh->refcount) - qh_destroy(qh); -} - /*-------------------------------------------------------------------------*/ /* The queue heads and transfer descriptors are managed from pools tied @@ -138,11 +120,11 @@ static void ehci_mem_cleanup (struct ehci_hcd *ehci) { free_cached_lists(ehci); if (ehci->async) - qh_put (ehci->async); + qh_destroy(ehci, ehci->async); ehci->async = NULL; if (ehci->dummy) - qh_put(ehci->dummy); + qh_destroy(ehci, ehci->dummy); ehci->dummy = NULL; /* DMA consistent memory and pools */ diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 4378bf72bbac..7d117bbffac1 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -265,7 +265,6 @@ __acquires(ehci->lock) /* ... update hc-wide periodic stats (for usbfs) */ ehci_to_hcd(ehci)->self.bandwidth_int_reqs--; } - qh_put (qh); } if (unlikely(urb->unlinked)) { @@ -946,7 +945,7 @@ qh_make ( ehci_dbg(ehci, "bogus dev %p speed %d\n", urb->dev, urb->dev->speed); done: - qh_put (qh); + qh_destroy(ehci, qh); return NULL; } @@ -1003,7 +1002,6 @@ static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh) head->qh_next.qh = qh; head->hw->hw_next = dma; - qh_get(qh); qh->xacterrs = 0; qh->qh_state = QH_STATE_LINKED; /* qtd completions reported later by interrupt */ @@ -1090,7 +1088,7 @@ static struct ehci_qh *qh_append_tds ( wmb (); dummy->hw_token = token; - urb->hcpriv = qh_get (qh); + urb->hcpriv = qh; } } return qh; @@ -1167,7 +1165,6 @@ static void end_unlink_async (struct ehci_hcd *ehci) // qh->hw_next = cpu_to_hc32(qh->qh_dma); qh->qh_state = QH_STATE_IDLE; qh->qh_next.qh = NULL; - qh_put (qh); // refcount from reclaim /* other unlink(s) may be pending (in QH_STATE_UNLINK_WAIT) */ next = qh->reclaim; @@ -1186,7 +1183,6 @@ static void end_unlink_async (struct ehci_hcd *ehci) && ehci->async->qh_next.qh == NULL) timer_action (ehci, TIMER_ASYNC_OFF); } - qh_put(qh); /* refcount from async list */ if (next) { ehci->reclaim = NULL; @@ -1230,7 +1226,7 @@ static void start_unlink_async (struct ehci_hcd *ehci, struct ehci_qh *qh) } qh->qh_state = QH_STATE_UNLINK; - ehci->reclaim = qh = qh_get (qh); + ehci->reclaim = qh; prev = ehci->async; while (prev->qh_next.qh != qh) @@ -1283,12 +1279,10 @@ static void scan_async (struct ehci_hcd *ehci) * gets unlinked then ehci->qh_scan_next is adjusted * in start_unlink_async(). */ - qh = qh_get(qh); temp = qh_completions(ehci, qh); if (qh->needs_rescan) unlink_async(ehci, qh); qh->unlink_time = jiffies + EHCI_SHRINK_JIFFIES; - qh_put(qh); if (temp != 0) goto rescan; } diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 33182c6d1ff9..027df3de2dc9 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -606,7 +606,6 @@ static int qh_link_periodic (struct ehci_hcd *ehci, struct ehci_qh *qh) } qh->qh_state = QH_STATE_LINKED; qh->xacterrs = 0; - qh_get (qh); /* update per-qh bandwidth for usbfs */ ehci_to_hcd(ehci)->self.bandwidth_allocated += qh->period @@ -650,7 +649,6 @@ static int qh_unlink_periodic(struct ehci_hcd *ehci, struct ehci_qh *qh) /* qh->qh_next still "live" to HC */ qh->qh_state = QH_STATE_UNLINK; qh->qh_next.ptr = NULL; - qh_put (qh); /* maybe turn off periodic schedule */ return disable_periodic(ehci); @@ -2340,7 +2338,7 @@ restart: switch (hc32_to_cpu(ehci, type)) { case Q_TYPE_QH: /* handle any completions */ - temp.qh = qh_get (q.qh); + temp.qh = q.qh; type = Q_NEXT_TYPE(ehci, q.qh->hw->hw_next); q = q.qh->qh_next; if (temp.qh->stamp != ehci->periodic_stamp) { @@ -2351,7 +2349,6 @@ restart: temp.qh->needs_rescan)) intr_deschedule(ehci, temp.qh); } - qh_put (temp.qh); break; case Q_TYPE_FSTN: /* for "save place" FSTNs, look at QH entries diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index 85c3572155d1..f7a59f5d70c6 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -350,16 +350,7 @@ struct ehci_qh { struct ehci_qtd *dummy; struct ehci_qh *reclaim; /* next to reclaim */ - struct ehci_hcd *ehci; unsigned long unlink_time; - - /* - * Do NOT use atomic operations for QH refcounting. On some CPUs - * (PPC7448 for example), atomic operations cannot be performed on - * memory that is cache-inhibited (i.e. being used for DMA). - * Spinlocks are used to protect all QH fields. - */ - u32 refcount; unsigned stamp; u8 needs_rescan; /* Dequeue during giveback */ -- cgit v1.2.3