On 10/15/2018 02:00 PM, Dan Williams wrote:
> In addition to not allowing ARS start while the background thread is
> actively running, prevent ARS start while any scrub request is pending.
>
> This aligns the window for ARS start submission with the status of ARS
> reported via sysfs. Previously userspace could sneak its own ARS start
> requests in while sysfs reported -EBUSY.
>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
> ---
> Changes in v2:
> * Require acpi_desc->scrub_spa to be NULL to prevent requests being sent
> while a scrub is active, or whose results are waiting to be reaped.
>
> drivers/acpi/nfit/core.c | 19 ++++++++++++++-----
> 1 file changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index f7efcd9843e0..253c0e85554d 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -3364,6 +3364,8 @@ static int __acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
> struct nvdimm *nvdimm, unsigned int cmd)
> {
> struct acpi_nfit_desc *acpi_desc = to_acpi_nfit_desc(nd_desc);
> + struct nfit_spa *nfit_spa;
> + int rc = 0;
>
> if (nvdimm)
> return 0;
> @@ -3373,13 +3375,20 @@ static int __acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
> /*
> * The kernel and userspace may race to initiate a scrub, but
> * the scrub thread is prepared to lose that initial race. It
> - * just needs guarantees that any ars it initiates are not
> - * interrupted by any intervening start reqeusts from userspace.
> + * just needs guarantees that any ARS it initiates are not
> + * interrupted by any intervening start requests from userspace.
> */
> - if (work_busy(&acpi_desc->dwork.work))
> - return -EBUSY;
> + mutex_lock(&acpi_desc->init_mutex);
> + list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
> + if (acpi_desc->scrub_spa
> + || test_bit(ARS_REQ_SHORT, &nfit_spa->ars_state)
> + || test_bit(ARS_REQ_LONG, &nfit_spa->ars_state)) {
> + rc = -EBUSY;
> + break;
> + }
> + mutex_unlock(&acpi_desc->init_mutex);
>
> - return 0;
> + return rc;
> }
>
> /* prevent security commands from being issued via ioctl */
>
