From 87bf572e19a092cc9cc77d5a00d543a2b628c142 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Mon, 22 Feb 2016 21:50:31 -0800 Subject: nfit: disable userspace initiated ars during scrub 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 --- drivers/acpi/nfit.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) (limited to 'drivers/acpi/nfit.c') diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c index 3646501..0def4eb 100644 --- a/drivers/acpi/nfit.c +++ b/drivers/acpi/nfit.c @@ -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); -- cgit v1.1