From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Boyd Subject: Re: [PATCH v2 08/22] usb: chipidea: Remove locking in ci_udc_start() Date: Fri, 05 Aug 2016 14:53:56 -0700 Message-ID: <147043403652.26915.10865210145828633146@sboyd-linaro> References: <20160707222114.1673-1-stephen.boyd@linaro.org> <20160707222114.1673-9-stephen.boyd@linaro.org> <20160708094528.GF20485@shlinux2> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160708094528.GF20485@shlinux2> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Peter Chen Cc: Felipe Balbi , Arnd Bergmann , Neil Armstrong , linux-arm-msm@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Bjorn Andersson , Peter Chen , Greg Kroah-Hartman , Andy Gross , linux-arm-kernel@lists.infradead.org List-Id: linux-arm-msm@vger.kernel.org Quoting Peter Chen (2016-07-08 02:45:28) > On Thu, Jul 07, 2016 at 03:20:59PM -0700, Stephen Boyd wrote: > > We don't call hw_device_reset() with the ci->lock held, so it > > doesn't seem like this lock here is protecting anything. Let's > > just remove it. This allows us to call sleeping functions like > > phy_init() from within the CI_HDRC_CONTROLLER_RESET_EVENT hook. > > > > Cc: Peter Chen > > Cc: Greg Kroah-Hartman > > Signed-off-by: Stephen Boyd > > --- > > drivers/usb/chipidea/udc.c | 3 --- > > 1 file changed, 3 deletions(-) > > > > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c > > index 065f5d97aa67..f16be4710cdb 100644 > > --- a/drivers/usb/chipidea/udc.c > > +++ b/drivers/usb/chipidea/udc.c > > @@ -1719,7 +1719,6 @@ static int ci_udc_start(struct usb_gadget *gadget, > > struct usb_gadget_driver *driver) > > { > > struct ci_hdrc *ci = container_of(gadget, struct ci_hdrc, gadget); > > - unsigned long flags; > > int retval = -ENOMEM; > > > > if (driver->disconnect == NULL) > > @@ -1746,7 +1745,6 @@ static int ci_udc_start(struct usb_gadget *gadget, > > > > pm_runtime_get_sync(&ci->gadget.dev); > > if (ci->vbus_active) { > > - spin_lock_irqsave(&ci->lock, flags); > > hw_device_reset(ci); > > } else { > > usb_udc_vbus_handler(&ci->gadget, false); > > @@ -1755,7 +1753,6 @@ static int ci_udc_start(struct usb_gadget *gadget, > > } > > > > retval = hw_device_state(ci, ci->ep0out->qh.dma); > > - spin_unlock_irqrestore(&ci->lock, flags); > > if (retval) > > pm_runtime_put_sync(&ci->gadget.dev); > > > > The main purpose for this is disabling interrupt when reset controller, > in case the unexpected interrupts occur. > > You can move this between hw_device_state. > Ok, but we don't hold the ci->lock in ci_udc_vbus_session(). Is that a bug as well? From mboxrd@z Thu Jan 1 00:00:00 1970 From: stephen.boyd@linaro.org (Stephen Boyd) Date: Fri, 05 Aug 2016 14:53:56 -0700 Subject: [PATCH v2 08/22] usb: chipidea: Remove locking in ci_udc_start() In-Reply-To: <20160708094528.GF20485@shlinux2> References: <20160707222114.1673-1-stephen.boyd@linaro.org> <20160707222114.1673-9-stephen.boyd@linaro.org> <20160708094528.GF20485@shlinux2> Message-ID: <147043403652.26915.10865210145828633146@sboyd-linaro> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Quoting Peter Chen (2016-07-08 02:45:28) > On Thu, Jul 07, 2016 at 03:20:59PM -0700, Stephen Boyd wrote: > > We don't call hw_device_reset() with the ci->lock held, so it > > doesn't seem like this lock here is protecting anything. Let's > > just remove it. This allows us to call sleeping functions like > > phy_init() from within the CI_HDRC_CONTROLLER_RESET_EVENT hook. > > > > Cc: Peter Chen > > Cc: Greg Kroah-Hartman > > Signed-off-by: Stephen Boyd > > --- > > drivers/usb/chipidea/udc.c | 3 --- > > 1 file changed, 3 deletions(-) > > > > diff --git a/drivers/usb/chipidea/udc.c b/drivers/usb/chipidea/udc.c > > index 065f5d97aa67..f16be4710cdb 100644 > > --- a/drivers/usb/chipidea/udc.c > > +++ b/drivers/usb/chipidea/udc.c > > @@ -1719,7 +1719,6 @@ static int ci_udc_start(struct usb_gadget *gadget, > > struct usb_gadget_driver *driver) > > { > > struct ci_hdrc *ci = container_of(gadget, struct ci_hdrc, gadget); > > - unsigned long flags; > > int retval = -ENOMEM; > > > > if (driver->disconnect == NULL) > > @@ -1746,7 +1745,6 @@ static int ci_udc_start(struct usb_gadget *gadget, > > > > pm_runtime_get_sync(&ci->gadget.dev); > > if (ci->vbus_active) { > > - spin_lock_irqsave(&ci->lock, flags); > > hw_device_reset(ci); > > } else { > > usb_udc_vbus_handler(&ci->gadget, false); > > @@ -1755,7 +1753,6 @@ static int ci_udc_start(struct usb_gadget *gadget, > > } > > > > retval = hw_device_state(ci, ci->ep0out->qh.dma); > > - spin_unlock_irqrestore(&ci->lock, flags); > > if (retval) > > pm_runtime_put_sync(&ci->gadget.dev); > > > > The main purpose for this is disabling interrupt when reset controller, > in case the unexpected interrupts occur. > > You can move this between hw_device_state. > Ok, but we don't hold the ci->lock in ci_udc_vbus_session(). Is that a bug as well?