| Message ID | 1394447948-14778-2-git-send-email-vinod.koul@intel.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Vinod Koul |
| Headers | show |
On 10/03/2014 11:39, Vinod Koul : > As discussed in [1] the tasklet_disable is not a proper function for teardown. > The driver also uses correct method of tasklet_kill. So remove tasklet_disable > > [1]: http://lwn.net/Articles/588457/ > > Reported-by: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: Vinod Koul <vinod.koul@intel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Thanks. > --- > drivers/dma/at_hdmac.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c > index e2c04dc..c13a3bb 100644 > --- a/drivers/dma/at_hdmac.c > +++ b/drivers/dma/at_hdmac.c > @@ -1569,7 +1569,6 @@ static int at_dma_remove(struct platform_device *pdev) > > /* Disable interrupts */ > atc_disable_chan_irq(atdma, chan->chan_id); > - tasklet_disable(&atchan->tasklet); > > tasklet_kill(&atchan->tasklet); > list_del(&chan->device_node); >
On Mon, 10 Mar 2014, Vinod Koul wrote: > As discussed in [1] the tasklet_disable is not a proper function for teardown. > The driver also uses correct method of tasklet_kill. So remove tasklet_disable > > [1]: http://lwn.net/Articles/588457/ Please add an explanation why that driver is otherwise safe. > Reported-by: Thomas Gleixner <tglx@linutronix.de> > Signed-off-by: Vinod Koul <vinod.koul@intel.com> > --- > drivers/dma/at_hdmac.c | 1 - > 1 files changed, 0 insertions(+), 1 deletions(-) > > diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c > index e2c04dc..c13a3bb 100644 > --- a/drivers/dma/at_hdmac.c > +++ b/drivers/dma/at_hdmac.c > @@ -1569,7 +1569,6 @@ static int at_dma_remove(struct platform_device *pdev) > > /* Disable interrupts */ > atc_disable_chan_irq(atdma, chan->chan_id); > - tasklet_disable(&atchan->tasklet); > > tasklet_kill(&atchan->tasklet); > list_del(&chan->device_node); > -- > 1.7.0.4 > > -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Mar 10, 2014 at 08:13:57PM +0100, Thomas Gleixner wrote: > > On Mon, 10 Mar 2014, Vinod Koul wrote: > > > As discussed in [1] the tasklet_disable is not a proper function for teardown. > > The driver also uses correct method of tasklet_kill. So remove tasklet_disable > > > > [1]: http://lwn.net/Articles/588457/ > > Please add an explanation why that driver is otherwise safe. sure... Adding below as changelog to this, pls let me know if you are okay with this ---- As discussed in [1] the tasklet_disable is not a proper function for teardown. We need to ensure irq is disabled, followed by ensuring that don't schedule any more tasklets and then its safe to use tasklet_kill(). Here in at_hdmac driver we use free_irq() before tasklet_kill(). The free_irq() will ensure that the irq is disabled and also wait till all scheduled interrupts are executed by invoking synchronize_irq(). So we need to only do tasklet_kill() after invoking free_irq() [1]: http://lwn.net/Articles/588457/
On Tue, 11 Mar 2014, Vinod Koul wrote: > On Mon, Mar 10, 2014 at 08:13:57PM +0100, Thomas Gleixner wrote: > > > > On Mon, 10 Mar 2014, Vinod Koul wrote: > > > > > As discussed in [1] the tasklet_disable is not a proper function for teardown. > > > The driver also uses correct method of tasklet_kill. So remove tasklet_disable > > > > > > [1]: http://lwn.net/Articles/588457/ > > > > Please add an explanation why that driver is otherwise safe. > sure... > > > Adding below as changelog to this, pls let me know if you are okay with this > > ---- > > As discussed in [1] the tasklet_disable is not a proper function for teardown. > We need to ensure irq is disabled, followed by ensuring that don't schedule any > more tasklets and then its safe to use tasklet_kill(). > > Here in at_hdmac driver we use free_irq() before tasklet_kill(). The free_irq() > will ensure that the irq is disabled and also wait till all scheduled interrupts > are executed by invoking synchronize_irq(). So we need to only do tasklet_kill() > after invoking free_irq() > > [1]: http://lwn.net/Articles/588457/ Reviewed-by: Thomas Gleixner <tglx@linutronix.de> -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index e2c04dc..c13a3bb 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -1569,7 +1569,6 @@ static int at_dma_remove(struct platform_device *pdev) /* Disable interrupts */ atc_disable_chan_irq(atdma, chan->chan_id); - tasklet_disable(&atchan->tasklet); tasklet_kill(&atchan->tasklet); list_del(&chan->device_node);
As discussed in [1] the tasklet_disable is not a proper function for teardown. The driver also uses correct method of tasklet_kill. So remove tasklet_disable [1]: http://lwn.net/Articles/588457/ Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com> --- drivers/dma/at_hdmac.c | 1 - 1 files changed, 0 insertions(+), 1 deletions(-)