linux-kernel - Re: [PATCH v3 1/3] staging: r8188eu: remove _io

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Date:   Mon, 6 Sep 2021 16:08:20 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     Pavel Skripkin <paskripkin@...il.com>
Cc:     "Fabio M. De Francesco" <fmdefrancesco@...il.com>,
        Larry Finger <Larry.Finger@...inger.net>,
        Phillip Potter <phil@...lpotter.co.uk>,
        linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 1/3] staging: r8188eu: remove _io_ops structure

On Mon, Sep 06, 2021 at 05:01:09PM +0300, Pavel Skripkin wrote:
> On 9/6/21 4:56 PM, Greg Kroah-Hartman wrote:
> > On Sun, Sep 05, 2021 at 12:00:46AM +0200, Fabio M. De Francesco wrote:
> > > -void _rtw_read_mem(struct adapter *adapter, u32 addr, u32 cnt, u8 *pmem)
> > > -{
> > > -	void (*_read_mem)(struct intf_hdl *pintfhdl, u32 addr, u32 cnt, u8 *pmem);
> > > -	struct io_priv *pio_priv = &adapter->iopriv;
> > > -	struct	intf_hdl		*pintfhdl = &pio_priv->intf;
> > > -
> > > -
> > > -	if (adapter->bDriverStopped || adapter->bSurpriseRemoved)
> > > -	     return;
> > > -	_read_mem = pintfhdl->io_ops._read_mem;
> > > -	_read_mem(pintfhdl, addr, cnt, pmem);
> > > -
> > > -}
> > 
> > This is odd, in that it resolves down to usb_read_mem which does
> > nothing at all.
> > 
> > And then no one calls this at all either?
> > 
> 
> Yep, there is no caller of this function... Idk why this was added :)

PCI devices require a read after a write to ensure that the write has
completed.  Odds are this is left over from that.

thanks,

greg k-h