Messages in this thread | | | Date | Wed, 17 Jun 2009 16:28:19 +0200 | From | Joerg Roedel <> | Subject | Re: bug in tty ldisc and friends |
| |
On Wed, Jun 17, 2009 at 04:10:18PM +0200, Ingo Molnar wrote: > > * Peter Zijlstra <a.p.zijlstra@chello.nl> wrote: > > > On Tue, 2009-06-16 at 12:36 +0200, Ingo Molnar wrote: > > > > > +++ b/lib/dma-debug.c > > > @@ -62,6 +62,8 @@ struct dma_debug_entry { > > > #endif > > > }; > > > > > > +static struct lock_class_key hash_bucket_class; > > > + > > > struct hash_bucket { > > > struct list_head list; > > > spinlock_t lock; > > > @@ -716,7 +718,8 @@ void dma_debug_init(u32 num_entries) > > > > > > for (i = 0; i < HASH_SIZE; ++i) { > > > INIT_LIST_HEAD(&dma_entry_hash[i].list); > > > - dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED; > > > + spin_lock_init(&dma_entry_hash[i].lock); > > > + lockdep_set_lock_class(&dma_entry_hash[i].lock, &hash_bucket_class); > > > } > > > > > > if (dma_debug_fs_init() != 0) { > > > > I don't see what you need that lockdep_set_class() for, the > > spin_lock_init() would already set a class specific to the > > callsite. And since all these buckets are initialized from the > > same place (ie, this loop), they'd all share the same class. > > > > Its just that the old style SPIN_LOCK_UNLOCKED doesn't set a class > > and then reverts to the static address of the lock object itself > > that these locks used to have different classes. > > > > So in short, yes the above patch should fix it, but it could be > > done shorter.. > > Indeed ... Joerg: mind removing the set_class complication and just > switch it to spin_lock_init().
Ok, done.
> > > we really should do another round of SPIN_LOCK_UNLOCKED cleanups > > and finally remove that thing. > > +1.
A first step might be updating the documentation under Documentation/spinlocks.txt to teach people the new right way of initializing spinlocks :-)
Joerg
-- | Advanced Micro Devices GmbH Operating | Karl-Hammerschmidt-Str. 34, 85609 Dornach bei München System | Research | Geschäftsführer: Thomas M. McCoy, Giuliano Meroni Center | Sitz: Dornach, Gemeinde Aschheim, Landkreis München | Registergericht München, HRB Nr. 43632
-- 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/
| |