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Message-ID: <459E896C.4050309@ericsson.com>
Date: Fri, 05 Jan 2007 17:22:52 +0000
From: Jon Maloy <jon.maloy@...csson.com>
To: Jarek Poplawski <jarkao2@...pl>
CC: Eric Sesterhenn <snakebyte@....de>,
Per Liden <per.liden@...csson.com>, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org,
"'tipc-discussion@...ts.sourceforge.net'"
<tipc-discussion@...ts.sourceforge.net>
Subject: Re: [PATCH] tipc: checking returns and Re: Possible Circular Locking
in TIPC
Jarek Poplawski wrote:
>
>If you are sure there is no circular locking possible
>between these two functions and this entry->lock here
>isn't endangered by other functions, you could try to
>make lockdep "silent" like this:
>
>
> write_lock_bh(&ref_table_lock);
> if (tipc_ref_table.first_free) {
> index = tipc_ref_table.first_free;
> entry = &(tipc_ref_table.entries[index]);
> index_mask = tipc_ref_table.index_mask;
> /* take lock in case a previous user of entry still holds it */
>
>- spin_lock_bh(&entry->lock, );
>+ local_bh_disable();
>+ spin_lock_nested(&entry->lock, SINGLE_DEPTH_NESTING);
>
> next_plus_upper = entry->data.next_plus_upper;
> tipc_ref_table.first_free = next_plus_upper & index_mask;
> reference = (next_plus_upper & ~index_mask) + index;
> entry->data.reference = reference;
> entry->object = object;
> if (lock != 0)
> *lock = &entry->lock;
>
>/* may stay as is or: */
>- spin_unlock_bh(&entry->lock);
>+ spin_unlock(&entry->lock);
>+ local_bh_enable();
>
> }
> write_unlock_bh(&ref_table_lock);
>
>
>
>
Looks like an acceptable solution. I will try this.
Thanks
///Jon
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