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From c3b527a21104b6bb61558fba6c65aa80f63e0772 Mon Sep 17 00:00:00 2001
From: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Date: Thu, 26 Mar 2009 17:36:57 -0700
Subject: [PATCH] usb: musb_host, minor enqueue locking fix (v2)
Someone noted that the enqueue path used an unlocked access
for usb_host_endpoint->hcpriv ... fix that, by being safe
and always accessing it under spinlock protection.
Signed-off-by: David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
---
drivers/usb/musb/musb_host.c | 17 ++++++++---------
1 files changed, 8 insertions(+), 9 deletions(-)
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
index 499c431..ff09595 100644
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -1841,7 +1841,7 @@ static int musb_urb_enqueue(
unsigned long flags;
struct musb *musb = hcd_to_musb(hcd);
struct usb_host_endpoint *hep = urb->ep;
- struct musb_qh *qh = hep->hcpriv;
+ struct musb_qh *qh;
struct usb_endpoint_descriptor *epd = &hep->desc;
int ret;
unsigned type_reg;
@@ -1853,22 +1853,21 @@ static int musb_urb_enqueue(
spin_lock_irqsave(&musb->lock, flags);
ret = usb_hcd_link_urb_to_ep(hcd, urb);
+ qh = ret ? NULL : hep->hcpriv;
+ if (qh)
+ urb->hcpriv = qh;
spin_unlock_irqrestore(&musb->lock, flags);
- if (ret)
- return ret;
/* DMA mapping was already done, if needed, and this urb is on
- * hep->urb_list ... so there's little to do unless hep wasn't
- * yet scheduled onto a live qh.
+ * hep->urb_list now ... so we're done, unless hep wasn't yet
+ * scheduled onto a live qh.
*
* REVISIT best to keep hep->hcpriv valid until the endpoint gets
* disabled, testing for empty qh->ring and avoiding qh setup costs
* except for the first urb queued after a config change.
*/
- if (qh) {
- urb->hcpriv = qh;
- return 0;
- }
+ if (qh || ret)
+ return ret;
/* Allocate and initialize qh, minimizing the work done each time
* hw_ep gets reprogrammed, or with irqs blocked. Then schedule it.
--
1.6.0.4
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