Re: [PATCH 2/6] nfit, address-range-scrub: fix scrub in-progress reporting

[Dave Jiang <dave.jiang@intel.com>]

On 4/2/2018 9:46 PM, Dan Williams wrote:
> There is a small window whereby ARS scan requests can schedule work that
> userspace will miss when polling scrub_show. Hold the init_mutex lock
> over calls to report the status to close this potential escape. Also,
> make sure that requests to cancel the ARS workqueue are treated as an
> idle event.
>
> Cc: <stable@vger.kernel.org>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Fixes: 37b137ff8c83 ("nfit, libnvdimm: allow an ARS scrub...")
> Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>


> ---
>   drivers/acpi/nfit/core.c |    5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index ea9f3e727fef..2a1fc3817a81 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -1249,8 +1249,11 @@ static ssize_t scrub_show(struct device *dev,
>   	if (nd_desc) {
>   		struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
>   
> +		mutex_lock(&acpi_desc->init_mutex);
>   		rc = sprintf(buf, "%d%s", acpi_desc->scrub_count,
> -				(work_busy(&acpi_desc->work)) ? "+\n" : "\n");
> +				work_busy(&acpi_desc->work)
> +				&& !acpi_desc->cancel ? "+\n" : "\n");
> +		mutex_unlock(&acpi_desc->init_mutex);
>   	}
>   	device_unlock(dev);
>   	return rc;
>
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