[PATCH v2 6/8] MTD: xway: fix nand locking

[Hauke Mehrtens]

On 06/19/2016 02:53 PM, Richard Weinberger wrote:
> Am 19.06.2016 um 14:41 schrieb Boris Brezillon:
>> On Sat, 18 Jun 2016 21:14:10 +0200
>> Hauke Mehrtens <hauke at hauke-m.de> wrote:
>>
>>> From: John Crispin <john at phrozen.org>
>>>
>>> The external Bus Unit (EBU) can control different flash devices, but
>>> these NAND flash commands have to be atomic and should not be
>>> interrupted in between. Lock the EBU from the beginning of the command
>>> till the end by moving the lock to the chip select.
>>>
>>> Signed-off-by: John Crispin <john at phrozen.org>
>>> Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
>>> ---
>>>  drivers/mtd/nand/xway_nand.c | 20 ++++----------------
>>>  1 file changed, 4 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
>>> index 1511bdb..064ee41 100644
>>> --- a/drivers/mtd/nand/xway_nand.c
>>> +++ b/drivers/mtd/nand/xway_nand.c
>>> @@ -94,13 +94,16 @@ static void xway_reset_chip(struct nand_chip *chip)
>>>  
>>>  static void xway_select_chip(struct mtd_info *mtd, int chip)
>>>  {
>>> +	static unsigned long csflags;
> 
> Why is csflags static? AFAICT this is racy then...

Because the lock is taken when the chip is selected and it is unlocked
when the chip select is deactivated again. This should be part of the
private driver struct.

Hauke