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From:   Rex Zhang <rex.zhang@intel.com>
To:     tom.zanussi@linux.intel.com
Cc:     dave.jiang@intel.com, davem@davemloft.net,
        dmaengine@vger.kernel.org, fenghua.yu@intel.com,
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        linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org,
        pavel@ucw.cz, rex.zhang@intel.com, tony.luck@intel.com,
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Subject: Re: [PATCH v11 11/14] crypto: iaa - Add support for deflate-iaa compression algorithm
Date:   Tue,  5 Dec 2023 10:26:55 +0800
Message-Id: <20231205022655.3616965-1-rex.zhang@intel.com>
In-Reply-To: <1a44f8396c6b7014de9b9bde4d5f5a4dbf0ef7a1.camel@linux.intel.com>
References: <1a44f8396c6b7014de9b9bde4d5f5a4dbf0ef7a1.camel@linux.intel.com>
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Hi Tom,

On 2023-12-04 at 15:41:46 -0600, Tom Zanussi wrote:
> Hi Rex,
> 
> On Mon, 2023-12-04 at 23:00 +0800, Rex Zhang wrote:
> > Hi, Tom,
> > 
> > On 2023-12-01 at 14:10:32 -0600, Tom Zanussi wrote:
> > 
> > [snip]
> > 
> > > +static int iaa_wq_put(struct idxd_wq *wq)
> > > +{
> > > +       struct idxd_device *idxd = wq->idxd;
> > > +       struct iaa_wq *iaa_wq;
> > > +       bool free = false;
> > > +       int ret = 0;
> > > +
> > > +       spin_lock(&idxd->dev_lock);
> > > +       iaa_wq = idxd_wq_get_private(wq);
> > > +       if (iaa_wq) {
> > > +               iaa_wq->ref--;
> > > +               if (iaa_wq->ref == 0 && iaa_wq->remove) {
> > > +                       __free_iaa_wq(iaa_wq);
> > > +                       idxd_wq_set_private(wq, NULL);
> > > +                       free = true;
> > > +               }
> > > +               idxd_wq_put(wq);
> > > +       } else {
> > > +               ret = -ENODEV;
> > > +       }
> > > +       spin_unlock(&idxd->dev_lock);
> > __free_iaa_wq() may cause schedule, whether it should be move out of
> > the
> > context between spin_lock() and spin_unlock()?
> 
> Yeah, I suppose it makes more sense to have it below anyway, will move
> it there.
> 
> > > +       if (free)
> > > +               kfree(iaa_wq);
> > > +
> > > +       return ret;
> > > +}
> > 
> > [snip]
> > 
> > > @@ -800,12 +1762,38 @@ static void iaa_crypto_remove(struct
> > > idxd_dev *idxd_dev)
> > >  
> > >         remove_iaa_wq(wq);
> > >  
> > > +       spin_lock(&idxd->dev_lock);
> > > +       iaa_wq = idxd_wq_get_private(wq);
> > > +       if (!iaa_wq) {
> > > +               spin_unlock(&idxd->dev_lock);
> > > +               pr_err("%s: no iaa_wq available to remove\n",
> > > __func__);
> > > +               goto out;
> > > +       }
> > > +
> > > +       if (iaa_wq->ref) {
> > > +               iaa_wq->remove = true;
> > > +       } else {
> > > +               wq = iaa_wq->wq;
> > > +               __free_iaa_wq(iaa_wq);
> > > +               idxd_wq_set_private(wq, NULL);
> > > +               free = true;
> > > +       }
> > > +       spin_unlock(&idxd->dev_lock);
> > __free_iaa_wq() may cause schedule, whether it should be move out of
> > the
> > context between spin_lock() and spin_unlock()?
> 
> Same.
> 
> > > +
> > > +       if (free)
> > > +               kfree(iaa_wq);
> > > +
> > >         idxd_drv_disable_wq(wq);
> > >         rebalance_wq_table();
> > >  
> > > -       if (nr_iaa == 0)
> > > +       if (nr_iaa == 0) {
> > > +               iaa_crypto_enabled = false;
> > Is it necessary to add iaa_unregister_compression_device() here?
> > All iaa devices are disabled cause the variable first_wq will be
> > true,
> > if enable wq, iaa_register_compression_device() will fail due to the
> > algorithm is existed.
> 
> No, this is required by review input from a previous version - the
> compression device can only be unregistered on module exit.
Do it mean disabling all WQs followed by enabling WQ is unacceptable?
User must do "rmmod iaa_crypto" before enabling WQ in this case.

Thanks.
> 
> Thanks,
> 
> Tom
> 
> > >                 free_wq_table();
> > > +               module_put(THIS_MODULE);
> > >  
> > > +               pr_info("iaa_crypto now DISABLED\n");
> > > +       }
> > > +out:
> > >         mutex_unlock(&iaa_devices_lock);
> > >         mutex_unlock(&wq->wq_lock);
> > >  }
> > 
> > [snip]
> > 
> > Thanks,
> > Rex Zhang
> > > -- 
> > > 2.34.1
> > > 
>