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authorPaul Mundt <lethal@linux-sh.org>2010-02-04 06:58:28 +0000
committerPaul Mundt <lethal@linux-sh.org>2010-02-05 11:53:28 +0900
commit2c940db250c1610d95ea5331dc819b8bd4db96ae (patch)
treefc1e5338940c4562d6b0e9df9e1a5525407b95c3 /drivers
parent2717568e7c44fe7dc3f4f52ea823811cfeede2b5 (diff)
downloadlinux-linaro-stable-2c940db250c1610d95ea5331dc819b8bd4db96ae.tar.gz
usb: r8a66597-hcd: Fix up spinlock recursion in root hub polling.
The current root hub polling code exhibits a spinlock recursion on the private controller lock. r8a66597_root_hub_control() is called from r8a66597_timer() which grabs the lock and disables IRQs. The following chain emerges: r8a66597_timer() <-- lock taken r8a66597_root_hub_control() r8a66597_check_syssts() usb_hcd_poll_rh_status() <-- acquires the same lock /* insert death here */ The entire chain requires IRQs to be disabled, so we just unlock and relock around the call to usb_hcd_poll_rh_status() while leaving the IRQ state unchanged. Signed-off-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/host/r8a66597-hcd.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/host/r8a66597-hcd.c b/drivers/usb/host/r8a66597-hcd.c
index 50a3e2d6a6cc..bee558aed427 100644
--- a/drivers/usb/host/r8a66597-hcd.c
+++ b/drivers/usb/host/r8a66597-hcd.c
@@ -1022,6 +1022,8 @@ static void start_root_hub_sampling(struct r8a66597 *r8a66597, int port,
/* this function must be called with interrupt disabled */
static void r8a66597_check_syssts(struct r8a66597 *r8a66597, int port,
u16 syssts)
+__releases(r8a66597->lock)
+__acquires(r8a66597->lock)
{
if (syssts == SE0) {
r8a66597_write(r8a66597, ~ATTCH, get_intsts_reg(port));
@@ -1039,7 +1041,9 @@ static void r8a66597_check_syssts(struct r8a66597 *r8a66597, int port,
usb_hcd_resume_root_hub(r8a66597_to_hcd(r8a66597));
}
+ spin_unlock(&r8a66597->lock);
usb_hcd_poll_rh_status(r8a66597_to_hcd(r8a66597));
+ spin_lock(&r8a66597->lock);
}
/* this function must be called with interrupt disabled */