[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20090109182339.GA31661@ioremap.net>
Date: Fri, 9 Jan 2009 21:23:39 +0300
From: Evgeniy Polyakov <zbr@...emap.net>
To: Joerg Roedel <joro@...tes.org>
Cc: Joerg Roedel <joerg.roedel@....com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
mingo@...hat.com
Subject: Re: [PATCH 03/16] dma-debug: add hash functions for dma_debug_entries
On Fri, Jan 09, 2009 at 07:14:46PM +0100, Joerg Roedel (joro@...tes.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
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists