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From: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>
To: linux-sh@vger.kernel.org
Subject: Re: [PATCH] usb: r8a66597-hcd: Fix up spinlock recursion in root hub
Date: Thu, 04 Feb 2010 09:24:04 +0000	[thread overview]
Message-ID: <4B6A9234.3010206@renesas.com> (raw)
In-Reply-To: <20100204065828.GB5574@linux-sh.org>

Paul Mundt wrote:
> 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>

Thank you very much again!
Acked-by: Yoshihiro Shimoda <shimoda.yoshihiro@renesas.com>

Thanks,
Yoshihiro Shimoda


      reply	other threads:[~2010-02-04  9:24 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-02-04  6:58 [PATCH] usb: r8a66597-hcd: Fix up spinlock recursion in root hub polling Paul Mundt
2010-02-04  9:24 ` Yoshihiro Shimoda [this message]

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