Re: [Linux-stable-mirror] [PATCH] eeprom: at24: correctly set the size for at24mac402

On Mon, Nov 27, 2017 at 11:06 PM, Bartosz Golaszewski brgl@bgdev.pl wrote:

There's an ilog2() expansion in AT24_DEVICE_MAGIC() which rounds down the actual size of EUI-48 byte array in at24mac402 eeproms to 4 from 6, making it impossible to read it all.

Fix it by manually adjusting the value in probe().

This patch contains a temporary fix that is suitable for stable branches. Eventually we'll probably remove the call to ilog2() while converting the magic values to actual structs.

•   /*
  

•    * REVISIT: the size of the EUI-48 byte array is 6 in at24mac402, while
  

•    * the call to ilog2() in AT24_DEVICE_MAGIC() rounds it down to 4.
  

•    *
  

•    * Eventually we'll get rid of the magic values altoghether in favor of
  

•    * real structs, but for now just manually set the right size.
  

•    */
  

•   if (chip.flags & AT24_FLAG_MAC && chip.byte_len == 4)
  

I didn't check, but do we need to test for len == 4 at all?

•           chip.byte_len = 6;