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nfit: disable userspace initiated ars during scrub

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While the nfit driver is issuing address range scrub commands and
reaping the results do not permit an ars_start command issued from
userspace.  The scrub thread assumes that all ars completions are for
scrubs initiated by platform firmware at boot, or by the nfit driver.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams
2016-02-22 21:50:31 -08:00
parent 1cf03c00e7
commit 87bf572e19
3 changed files with 38 additions and 5 deletions
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23
drivers/acpi/nfit.c
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@@ -2186,6 +2186,28 @@ static int acpi_nfit_flush_probe(struct nvdimm_bus_descriptor *nd_desc)
return wait_for_completion_interruptible(&flush.cmp);
}
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);
if (nvdimm)
return 0;
if (cmd != ND_CMD_ARS_START)
return 0;
/*
* 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.
*/
if (work_busy(&acpi_desc->work))
return -EBUSY;
return 0;
}
void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
{
struct nvdimm_bus_descriptor *nd_desc;
@@ -2197,6 +2219,7 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
nd_desc->provider_name = "ACPI.NFIT";
nd_desc->ndctl = acpi_nfit_ctl;
nd_desc->flush_probe = acpi_nfit_flush_probe;
nd_desc->clear_to_send = acpi_nfit_clear_to_send;
nd_desc->attr_groups = acpi_nfit_attribute_groups;
INIT_LIST_HEAD(&acpi_desc->spa_maps);