Re: [PATCH] MTD: OneNAND: Avoid deadlock in erase callback; release chip lock first.

["Jörn Engel" <joern@logfs.org>]

On Fri, 12 October 2007 10:34:01 +0300, Adrian Hunter wrote:
> 
> When the erase callback performs some other action on the flash, it's
> highly likely to deadlock unless we actually release the chip lock
> before calling it.
> 
> This patch mirrors that same change already done for NAND.
> 
> Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
> ---
>  drivers/mtd/onenand/onenand_base.c |    7 ++++---
>  1 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
> index a8c426b..dd28355 100644
> --- a/drivers/mtd/onenand/onenand_base.c
> +++ b/drivers/mtd/onenand/onenand_base.c
> @@ -1711,13 +1711,14 @@ static int onenand_erase(struct mtd_info *mtd, struct erase_info *instr)
>  erase_exit:
>  
>  	ret = instr->state == MTD_ERASE_DONE ? 0 : -EIO;

Can you move this line down as well?  There is no point in holding the
lock here and shrinking critical sections - even if only minimally -
is generally advantageous.

> -	/* Do call back function */
> -	if (!ret)
> -		mtd_erase_callback(instr);
>  
>  	/* Deselect and wake up anyone waiting on the device */
>  	onenand_release_device(mtd);
>  
> +	/* Do call back function */
> +	if (!ret)
> +		mtd_erase_callback(instr);
> +
>  	return ret;
>  }

Jörn

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