Messages in this thread | | | Date | Wed, 17 Jun 2009 16:10:18 +0200 | From | Ingo Molnar <> | Subject | Re: bug in tty ldisc and friends |
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* 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().
> we really should do another round of SPIN_LOCK_UNLOCKED cleanups > and finally remove that thing.
+1.
Ingo
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