From 2c940db250c1610d95ea5331dc819b8bd4db96ae Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Thu, 4 Feb 2010 06:58:28 +0000 Subject: [PATCH] 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 Acked-by: Yoshihiro Shimoda --- drivers/usb/host/r8a66597-hcd.c | 4 ++++ 1 file changed, 4 insertions(+) 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 */