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Re: [PATCHv7 6/7] eeprom: 93xx46: extend driver to plug into the NVMEM framework

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> >  static ssize_t
> > -eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
> > -		       struct bin_attribute *bin_attr,
> > -		       char *buf, loff_t off, size_t count)
> > +eeprom_93xx46_read(struct eeprom_93xx46_dev *edev, char *buf,
> > +		   unsigned off, size_t count)
> >  {
> > -	struct eeprom_93xx46_dev *edev;
> > -	struct device *dev;
> >  	ssize_t ret = 0;
> >  
> > -	dev = kobj_to_dev(kobj);
> > -	edev = dev_get_drvdata(dev);
> > +	if (unlikely(off >= edev->size))
> > +		return 0;
> > +	if ((off + count) > edev->size)
> > +		count = edev->size - off;
> > +	if (unlikely(!count))
> > +		return count;
> >  
> 
> I'm scratching my head, do you want to kind of revert
> the change https://lkml.org/lkml/2015/7/26/89 ? Why?

Hi Vladimir

I had not noticed you had removed this.
 
> If you know regmap_config.max_register, then all necessary
> boundary checks can be done inside NVMEM core.

You don't have to use NVMEM, you could use the regmap directly. It is
a public API. Also, during implementation, i did manage to get out of
bounds read passed into the drivers and they caused a crash. That
might of been AT24, i don't remember, but verifying is better than
possible crashing.

> > +/*
> > + * Provide a regmap interface, which is registered with the NVMEM
> > + * framework
> > +*/
> > +static int eeprom_93xx46_regmap_read(void *context, const void *reg,
> > +				     size_t reg_size, void *val,
> > +				     size_t val_size)
> > +{
> > +	struct eeprom_93xx46_dev *eeprom_93xx46 = context;
> > +	off_t offset = *(u32 *)reg;
> > +	int err;
> > +
> > +	err = eeprom_93xx46_read(eeprom_93xx46, val, offset, val_size);
> > +	if (err)
> > +		return err;
> > +	return 0;
> 
> return eeprom_93xx46_read(eeprom_93xx46, val, offset, val_size);

As i've said a few times now to a few different people reviewing these
patches, regmap wants either an error code or 0.

	 Andrew

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[PATCHv7 0/7] Convert exiting EEPROM drivers to NVMEM Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:00 +0100
  [PATCHv7 3/7] eeprom: at24: extend driver to plug into the NVMEM framework Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:00 +0100
    Re: [PATCHv7 3/7] eeprom: at24: extend driver to plug into the NVMEM  framework Vladimir Zapolskiy <vz@mleia.com> - 2016-03-02 22:50 +0100
      Re: [PATCHv7 3/7] eeprom: at24: extend driver to plug into the NVMEM  framework Andrew Lunn <andrew@lunn.ch> - 2016-03-02 22:50 +0100
        Re: [PATCHv7 3/7] eeprom: at24: extend driver to plug into the NVMEM  framework Vladimir Zapolskiy <vz@mleia.com> - 2016-03-03 00:10 +0100
  [PATCHv7 5/7] eeprom: at25: extend driver to plug into the NVMEM framework Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:10 +0100
    Re: [PATCHv7 5/7] eeprom: at25: extend driver to plug into the NVMEM  framework Vladimir Zapolskiy <vz@mleia.com> - 2016-03-02 23:00 +0100
  [PATCHv7 4/7] eeprom: at25: Remove in kernel API for accessing the EEPROM Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:10 +0100
    Re: [PATCHv7 4/7] eeprom: at25: Remove in kernel API for accessing  the EEPROM Wolfram Sang <wsa@the-dreams.de> - 2016-02-28 22:10 +0100
  [PATCHv7 6/7] eeprom: 93xx46: extend driver to plug into the NVMEM framework Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:10 +0100
    Re: [PATCHv7 6/7] eeprom: 93xx46: extend driver to plug into the  NVMEM framework Vladimir Zapolskiy <vz@mleia.com> - 2016-03-02 23:10 +0100
      Re: [PATCHv7 6/7] eeprom: 93xx46: extend driver to plug into the  NVMEM framework Andrew Lunn <andrew@lunn.ch> - 2016-03-02 23:30 +0100
        Re: [PATCHv7 6/7] eeprom: 93xx46: extend driver to plug into the  NVMEM framework Vladimir Zapolskiy <vz@mleia.com> - 2016-03-03 00:20 +0100
  [PATCHv7 7/7] misc: at24: replace memory_accessor with nvmem_device_read Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:10 +0100
    Re: [PATCHv7 7/7] misc: at24: replace memory_accessor with  nvmem_device_read Wolfram Sang <wsa@the-dreams.de> - 2016-02-28 22:10 +0100
  [PATCHv7 1/7] nvmem: Add flag to export NVMEM to root only Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:10 +0100
  [PATCHv7 2/7] nvmem: Add backwards compatibility support for older EEPROM drivers. Andrew Lunn <andrew@lunn.ch> - 2016-02-26 21:10 +0100
  Re: [PATCHv7 0/7] Convert exiting EEPROM drivers to NVMEM Greg KH <gregkh@linuxfoundation.org> - 2016-03-02 02:00 +0100

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