Re: [PATCH 03/10] i2c: i801: Make p2sb_spinlock a mutex

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Thu, Aug 05, 2021 at 10:49:39AM +0200, Jean Delvare wrote:
> On Sun, 01 Aug 2021 16:18:38 +0200, Heiner Kallweit wrote:
> > p2sb_spinlock is used in i801_add_tco_spt() only and in process context
> > only. Therefore a mutex is sufficient, and we can make the definition
> > local to i801_add_tco_spt().
> 
> Mika, no objection?

No objections from my side :)

Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

> > Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
> > ---
> >  drivers/i2c/busses/i2c-i801.c | 7 +++----
> >  1 file changed, 3 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
> > index bdb619bc0..504f02e1e 100644
> > --- a/drivers/i2c/busses/i2c-i801.c
> > +++ b/drivers/i2c/busses/i2c-i801.c
> > @@ -1492,12 +1492,11 @@ static const struct itco_wdt_platform_data spt_tco_platform_data = {
> >  	.version = 4,
> >  };
> >  
> > -static DEFINE_SPINLOCK(p2sb_spinlock);
> > -
> >  static struct platform_device *
> >  i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> >  		 struct resource *tco_res)
> >  {
> > +	static DEFINE_MUTEX(p2sb_mutex);
> 
> To be on the safe side, we should explicitly #include <linux/mutex.h>.
> 
> >  	struct resource *res;
> >  	unsigned int devfn;
> >  	u64 base64_addr;
> > @@ -1510,7 +1509,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> >  	 * enumerated by the PCI subsystem, so we need to unhide/hide it
> >  	 * to lookup the P2SB BAR.
> >  	 */
> > -	spin_lock(&p2sb_spinlock);
> > +	mutex_lock(&p2sb_mutex);
> >  
> >  	devfn = PCI_DEVFN(PCI_SLOT(pci_dev->devfn), 1);
> >  
> > @@ -1528,7 +1527,7 @@ i801_add_tco_spt(struct i801_priv *priv, struct pci_dev *pci_dev,
> >  	/* Hide the P2SB device, if it was hidden before */
> >  	if (hidden)
> >  		pci_bus_write_config_byte(pci_dev->bus, devfn, 0xe1, hidden);
> > -	spin_unlock(&p2sb_spinlock);
> > +	mutex_unlock(&p2sb_mutex);
> >  
> >  	res = &tco_res[1];
> >  	if (pci_dev->device == PCI_DEVICE_ID_INTEL_DNV_SMBUS)
> 
> Reviewed-by: Jean Delvare <jdelvare@suse.de>
> 
> -- 
> Jean Delvare
> SUSE L3 Support