[PATCH] [CFI] Prevent erase command invocation on suspended chip

[Nicolas Pitre]

On Wed, 7 Nov 2007, Alexander Belyakov wrote:

> Hello,
> 
> while running stress tests we have met cfi_cmdset_0001.c driver issue.
> Working on multipartitional devices with erase suspend on write
> feature enabled it is possible to get erase operation invoked on chip
> with suspended erase. get_chip() looses information about earlier
> suspended erase and new erase operation gets issued. New erase
> operations report successful completion, but blocks remain dirty
> causing, for example, JFFS2 error messages like:
> 
> ...
> Newly-erased block contained word 0x20031985 at offset 0x00200000
> Newly-erased block contained word 0x20031985 at offset 0x00280000
> Newly-erased block contained word 0x20031985 at offset 0x00240000
> ...
> 
> 
> The patch below fixes that issue.
> 
> Signed-off-by: Alexander Belyakov <alexander.belyakov at intel.com>

Acked-by: Nicolas Pitre <nico at cam.org>


> 
> diff -uNr a/drivers/mtd/chips/cfi_cmdset_0001.c
> b/drivers/mtd/chips/cfi_cmdset_0001.c
> --- a/drivers/mtd/chips/cfi_cmdset_0001.c	2007-11-06 11:40:24.000000000 +0300
> +++ b/drivers/mtd/chips/cfi_cmdset_0001.c	2007-11-06 20:37:03.000000000 +0300
> @@ -795,6 +795,7 @@
>  static int get_chip(struct map_info *map, struct flchip *chip,
> unsigned long adr, int mode)
>  {
>  	int ret;
> +	DECLARE_WAITQUEUE(wait, current);
> 
>   retry:
>  	if (chip->priv && (mode == FL_WRITING || mode == FL_ERASING
> @@ -851,6 +852,20 @@
>  			spin_unlock(contender->mutex);
>  		}
> 
> +		/* Check if we already have suspended erase
> +		 * on this chip. Sleep. */
> +		if (mode == FL_ERASING && shared->erasing
> +		    && shared->erasing->oldstate == FL_ERASING) {
> +			spin_unlock(&shared->lock);
> +			set_current_state(TASK_UNINTERRUPTIBLE);
> +			add_wait_queue(&chip->wq, &wait);
> +			spin_unlock(chip->mutex);
> +			schedule();
> +			remove_wait_queue(&chip->wq, &wait);
> +			spin_lock(chip->mutex);
> +			goto retry;
> +		}
> +
>  		/* We now own it */
>  		shared->writing = chip;
>  		if (mode == FL_ERASING)
> 


Nicolas