Messages in this thread | | | Date | Fri, 9 Jan 2009 21:23:39 +0300 | From | Evgeniy Polyakov <> | Subject | Re: [PATCH 03/16] dma-debug: add hash functions for dma_debug_entries |
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On Fri, Jan 09, 2009 at 07:14:46PM +0100, Joerg Roedel (joro@8bytes.org) wrote: > > > +static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry, > > > + unsigned long *flags) > > > +{ > > > + int idx = hash_fn(entry); > > > + unsigned long __flags; > > > + > > > + spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags); > > > + *flags = __flags; > > > + return &dma_entry_hash[idx]; > > > +} > > > + > > > +/* > > > + * Give up exclusive access to the hash bucket > > > + */ > > > +static void put_hash_bucket(struct hash_bucket *bucket, > > > + unsigned long *flags) > > > +{ > > > + unsigned long __flags = *flags; > > > + > > > + spin_unlock_irqrestore(&bucket->lock, __flags); > > > +} > > > > Why do you need such ugly helpers? > > Because everything else I thought about here was even more ugly. But > maybe you have a better idea? I tried to lock directly in the debug_ > functions. But this is ugly and unnecessary code duplication.
I believe that having direct locking in the debug_ functions is not a duplication, anyone will have a direct vision on the locking and hash array dereference, and this will be just one additional line compared to the get_* call and the same number of lines for the put :)
-- Evgeniy Polyakov
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