Date:   Mon, 25 Mar 2019 14:10:20 +0100
From:   Stanislaw Gruszka <sgruszka@redhat.com>
To:     Lorenzo Bianconi <lorenzo.bianconi@redhat.com>
Cc:     Lorenzo Bianconi <lorenzo@kernel.org>, nbd@nbd.name,
        linux-wireless@vger.kernel.org
Subject: Re: [PATCH] mt76: usb: reduce locking in mt76u_tx_tasklet
Message-ID: <20190325131019.GA19204@redhat.com>
References: <cover.1553437543.git.lorenzo@kernel.org>
 <1f489df8bc635660a1d1fb72400e5562504c0555.1553437543.git.lorenzo@kernel.org>
 <20190325125032.GB17956@redhat.com>
 <20190325130035.GA12885@localhost.localdomain>
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On Mon, Mar 25, 2019 at 02:00:36PM +0100, Lorenzo Bianconi wrote:
> > On Sun, Mar 24, 2019 at 03:51:43PM +0100, Lorenzo Bianconi wrote:
> > > +		int idx;
> > > +
> > >  		sq = &dev->q_tx[i];
> > >  		q = sq->q;
> > >  
> > > -		spin_lock_bh(&q->lock);
> > > -		while (true) {
> > > -			if (!q->entry[q->head].done || !q->queued)
> > > +		while (q->queued > n_queued) {
> > > +			if (!q->entry[q->head].done)
> > >  				break;
> > If you place done = false here you will not need additional idx
> > variable.
> 
> As Felix suggested, I would set done to false at the end of the loop, after
> tx_complete_skb
Why this is needed? 

> > >  			dev->drv->tx_complete_skb(dev, i, &entry);
> > > -			spin_lock_bh(&q->lock);
> > > +			q->entry[idx].done = false;
> > >  		}
> > >  
> > > +		spin_lock_bh(&q->lock);
> > This patch does not apply for me as there is missing
> > mt76_txq_schedule(dev, sq);
> 
> Sorry I forgot to mention this patch is based on
> https://patchwork.kernel.org/patch/10856027/. Have you applied it?
No.

Stanislaw