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Re: LLTX and netif_stop_queue

To: Roland Dreier <roland@xxxxxxxxxxx>
Subject: Re: LLTX and netif_stop_queue
From: jamal <hadi@xxxxxxxxxx>
Date: 19 Dec 2004 18:06:32 -0500
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>, netdev@xxxxxxxxxxx, openib-general@xxxxxxxxxx
In-reply-to: <52fz21ncgh.fsf@xxxxxxxxxxx>
Organization: jamalopolous
References: <52llbwoaej.fsf@xxxxxxxxxxx> <20041217214432.07b7b21e.davem@xxxxxxxxxxxxx> <1103484675.1050.158.camel@xxxxxxxxxxxxxxxx> <52fz21ncgh.fsf@xxxxxxxxxxx>
Reply-to: hadi@xxxxxxxxxx
Sender: netdev-bounce@xxxxxxxxxxx
On Sun, 2004-12-19 at 17:35, Roland Dreier wrote:
>     jamal> How about releasing the qlock only when the LLTX transmit
>     jamal> lock is grabbed? That should bring it to par with what it
>     jamal> was originally.
> 
> This seems a little risky.  I can't point to a specific deadlock but
> it doesn't seem right on general principles to unlock in a different
> order than you nested the locks when acquiring them -- if I understand
> correctly, you're suggesting lock(queue_lock), lock(tx_lock),
> unlock(queue_lock), unlock(tx_lock).

There is no deadlock. Thats exactly how things work. Try the patches i
posted. 

cheers,
jamal



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