Messages in this thread | | | Date | Fri, 25 Jul 2008 18:54:25 +1000 | From | "Dave Airlie" <> | Subject | Re: [PATCH 1/1 repost #1] DRM: don't enable irqs in locking |
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On Fri, Jul 25, 2008 at 6:42 PM, Jiri Slaby <jirislaby@gmail.com> wrote: > drm_lock_take(); and drm_lock_free(); are called from > drm_locked_tasklet_func(); which disables interrupts when grabbing its > spinlock. > > Don't allow these locking functions to re-enable interrupts when > the tasklet expects them disabled. I.e. use spin_lock_irqsave instead of > spin_lock_bh (with their unlock opposites).
Hmm this has bounced through 2-3 variations.. Thomas any ideas what the final correct answer is?
Dave.
> > We will get such a warnings otherwise: > ------------[ cut here ]------------ > WARNING: at kernel/softirq.c:136 local_bh_enable_ip+0x8b/0xb0() > Modules linked in: arc4 ecb crypto_blkcipher cryptomgr crypto_algapi ath5k usbhid mac80211 ohci1394 hid led_class floppy cfg80211 ff_memless ieee1394 rtc_cmos evdev [last unloaded: freq_table] > Pid: 0, comm: swapper Not tainted 2.6.26-rc8-mm1_64 #427 > > Call Trace: > <IRQ> [<ffffffff8023813f>] warn_on_slowpath+0x5f/0x90 > [...] > [<ffffffff8023e1fb>] local_bh_enable_ip+0x8b/0xb0 > [<ffffffff8055b2cf>] _spin_unlock_bh+0xf/0x20 > [<ffffffff803b0bd1>] drm_lock_take+0x81/0xe0 > [<ffffffff803b006b>] drm_locked_tasklet_func+0x4b/0xb0 > [<ffffffff8023daf9>] tasklet_hi_action+0x69/0xf0 > [<ffffffff8023e3e4>] __do_softirq+0x84/0xf0 > [stack snipped] > > Signed-off-by: Jiri Slaby <jirislaby@gmail.com> > Cc: David Airlie <airlied@linux.ie> > --- > drivers/gpu/drm/drm_lock.c | 12 +++++++----- > 1 files changed, 7 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/drm_lock.c b/drivers/gpu/drm/drm_lock.c > index 0998723..79943e4 100644 > --- a/drivers/gpu/drm/drm_lock.c > +++ b/drivers/gpu/drm/drm_lock.c > @@ -196,10 +196,11 @@ int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv) > int drm_lock_take(struct drm_lock_data *lock_data, > unsigned int context) > { > + unsigned long flags; > unsigned int old, new, prev; > volatile unsigned int *lock = &lock_data->hw_lock->lock; > > - spin_lock_bh(&lock_data->spinlock); > + spin_lock_irqsave(&lock_data->spinlock, flags); > do { > old = *lock; > if (old & _DRM_LOCK_HELD) > @@ -211,7 +212,7 @@ int drm_lock_take(struct drm_lock_data *lock_data, > } > prev = cmpxchg(lock, old, new); > } while (prev != old); > - spin_unlock_bh(&lock_data->spinlock); > + spin_unlock_irqrestore(&lock_data->spinlock, flags); > > if (_DRM_LOCKING_CONTEXT(old) == context) { > if (old & _DRM_LOCK_HELD) { > @@ -270,17 +271,18 @@ static int drm_lock_transfer(struct drm_lock_data *lock_data, > */ > int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context) > { > + unsigned long flags; > unsigned int old, new, prev; > volatile unsigned int *lock = &lock_data->hw_lock->lock; > > - spin_lock_bh(&lock_data->spinlock); > + spin_lock_irqsave(&lock_data->spinlock, flags); > if (lock_data->kernel_waiters != 0) { > drm_lock_transfer(lock_data, 0); > lock_data->idle_has_lock = 1; > - spin_unlock_bh(&lock_data->spinlock); > + spin_unlock_irqrestore(&lock_data->spinlock, flags); > return 1; > } > - spin_unlock_bh(&lock_data->spinlock); > + spin_unlock_irqrestore(&lock_data->spinlock, flags); > > do { > old = *lock; > -- > 1.5.6.2 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ >
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