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Date: Thu, 21 Jul 2016 15:40:02 -0400
From: Linda Knippers <linda.knippers@....com>
To: Vishal Verma <vishal.l.verma@...el.com>,
<linux-nvdimm@...ts.01.org>
CC: Tony Luck <tony.luck@...el.com>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
<linux-kernel@...r.kernel.org>, <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH v2 2/3] nfit, libnvdimm: allow an ARS scrub to be triggered
on demand
On 07/20/2016 09:50 PM, Vishal Verma wrote:
> Normally, an ARS (Address Range Scrub) only happens at
> boot/initialization time. There can however arise situations where a
> bus-wide rescan is needed - notably, in the case of discovering a latent
> media error, we should do a full rescan to figure out what other sectors
> are bad, and thus potentially avoid triggering an mce on them in the
> future. Also provide a sysfs trigger to start a bus-wide scrub.
I don't see anything in here that checks to see if the platform actually
supports ARS before setting all this stuff up. Setting up an MCE handler
and exposing a sysfs trigger for something that is optional and perhaps
not implemented doesn't seem helpful. Or is there a check that I missed?
-- ljk
>
> Cc: Dan Williams <dan.j.williams@...el.com>
> Cc: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Cc: <linux-acpi@...r.kernel.org>
> Cc: <linux-nvdimm@...ts.01.org>
> Signed-off-by: Vishal Verma <vishal.l.verma@...el.com>
> ---
> drivers/acpi/nfit.c | 123 +++++++++++++++++++++++++++++++++------
> drivers/acpi/nfit.h | 4 +-
> drivers/nvdimm/core.c | 7 +++
> include/linux/libnvdimm.h | 1 +
> tools/testing/nvdimm/test/nfit.c | 16 +++++
> 5 files changed, 131 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
> index ac6ddcc0..4e65255 100644
> --- a/drivers/acpi/nfit.c
> +++ b/drivers/acpi/nfit.c
> @@ -15,6 +15,7 @@
> #include <linux/module.h>
> #include <linux/mutex.h>
> #include <linux/ndctl.h>
> +#include <linux/sysfs.h>
> #include <linux/delay.h>
> #include <linux/list.h>
> #include <linux/acpi.h>
> @@ -806,8 +807,41 @@ static ssize_t revision_show(struct device *dev,
> }
> static DEVICE_ATTR_RO(revision);
>
> +/*
> + * This shows the number of full Address Range Scrubs that have been
> + * completed since driver load time. Userspace can wait on this using
> + * select/poll etc.
> + */
> +static ssize_t scrub_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
> + struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
> + struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
> +
> + return sprintf(buf, "%d\n", acpi_desc->scrub_count);
> +}
> +
> +static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc);
> +
> +static ssize_t scrub_store(struct device *dev,
> + struct device_attribute *attr, const char *buf, size_t size)
> +{
> + struct nvdimm_bus *nvdimm_bus = to_nvdimm_bus(dev);
> + struct nvdimm_bus_descriptor *nd_desc = to_nd_desc(nvdimm_bus);
> + struct acpi_nfit_desc *acpi_desc = to_acpi_desc(nd_desc);
> + int rc;
> +
> + rc = acpi_nfit_ars_rescan(acpi_desc);
> + if (rc)
> + return rc;
> + return size;
> +}
> +static DEVICE_ATTR_RW(scrub);
> +
> static struct attribute *acpi_nfit_attributes[] = {
> &dev_attr_revision.attr,
> + &dev_attr_scrub.attr,
> NULL,
> };
>
> @@ -2138,7 +2172,7 @@ static void acpi_nfit_async_scrub(struct acpi_nfit_desc *acpi_desc,
> unsigned int tmo = scrub_timeout;
> int rc;
>
> - if (nfit_spa->ars_done || !nfit_spa->nd_region)
> + if (!(nfit_spa->ars_required && nfit_spa->nd_region))
> return;
>
> rc = ars_start(acpi_desc, nfit_spa);
> @@ -2227,7 +2261,9 @@ static void acpi_nfit_scrub(struct work_struct *work)
> * firmware initiated scrubs to complete and then we go search for the
> * affected spa regions to mark them scanned. In the second phase we
> * initiate a directed scrub for every range that was not scrubbed in
> - * phase 1.
> + * phase 1. If we're called for a 'rescan', we harmlessly pass through
> + * the first phase, but really only care about running phase 2, where
> + * regions can be notified of new poison.
> */
>
> /* process platform firmware initiated scrubs */
> @@ -2330,14 +2366,17 @@ static void acpi_nfit_scrub(struct work_struct *work)
> * Flag all the ranges that still need scrubbing, but
> * register them now to make data available.
> */
> - if (nfit_spa->nd_region)
> - nfit_spa->ars_done = 1;
> - else
> + if (!nfit_spa->nd_region) {
> + nfit_spa->ars_required = 1;
> acpi_nfit_register_region(acpi_desc, nfit_spa);
> + }
> }
>
> list_for_each_entry(nfit_spa, &acpi_desc->spas, list)
> acpi_nfit_async_scrub(acpi_desc, nfit_spa);
> + acpi_desc->scrub_count++;
> + if (acpi_desc->scrub_count_state)
> + sysfs_notify_dirent(acpi_desc->scrub_count_state);
> mutex_unlock(&acpi_desc->init_mutex);
> }
>
> @@ -2495,6 +2534,27 @@ static int acpi_nfit_clear_to_send(struct nvdimm_bus_descriptor *nd_desc,
> return 0;
> }
>
> +static int acpi_nfit_ars_rescan(struct acpi_nfit_desc *acpi_desc)
> +{
> + struct device *dev = acpi_desc->dev;
> + struct nfit_spa *nfit_spa;
> +
> + if (work_busy(&acpi_desc->work))
> + return -EBUSY;
> +
> + list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
> + struct acpi_nfit_system_address *spa = nfit_spa->spa;
> +
> + if (nfit_spa_type(spa) != NFIT_SPA_PM)
> + continue;
> +
> + nfit_spa->ars_required = 1;
> + }
> + queue_work(nfit_wq, &acpi_desc->work);
> + dev_info(dev, "%s: ars_scan triggered\n", __func__);
> + return 0;
> +}
> +
> void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
> {
> struct nvdimm_bus_descriptor *nd_desc;
> @@ -2523,6 +2583,37 @@ void acpi_nfit_desc_init(struct acpi_nfit_desc *acpi_desc, struct device *dev)
> }
> EXPORT_SYMBOL_GPL(acpi_nfit_desc_init);
>
> +static struct acpi_nfit_desc *acpi_nfit_desc_alloc_register(struct device *dev)
> +{
> + struct acpi_nfit_desc *acpi_desc;
> + struct kernfs_node *nfit;
> + struct device *bus_dev;
> +
> + acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
> + if (!acpi_desc)
> + return ERR_PTR(-ENOMEM);
> +
> + acpi_nfit_desc_init(acpi_desc, dev);
> +
> + acpi_desc->nvdimm_bus = nvdimm_bus_register(dev, &acpi_desc->nd_desc);
> + if (!acpi_desc->nvdimm_bus)
> + return ERR_PTR(-ENOMEM);
> +
> + bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
> + nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
> + if (!nfit) {
> + dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
> + return ERR_PTR(-ENODEV);
> + }
> + acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
> + if (!acpi_desc->scrub_count_state) {
> + dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
> + return ERR_PTR(-ENODEV);
> + }
> +
> + return acpi_desc;
> +}
> +
> static int acpi_nfit_add(struct acpi_device *adev)
> {
> struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL };
> @@ -2540,13 +2631,9 @@ static int acpi_nfit_add(struct acpi_device *adev)
> return 0;
> }
>
> - acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
> - if (!acpi_desc)
> - return -ENOMEM;
> - acpi_nfit_desc_init(acpi_desc, &adev->dev);
> - acpi_desc->nvdimm_bus = nvdimm_bus_register(dev, &acpi_desc->nd_desc);
> - if (!acpi_desc->nvdimm_bus)
> - return -ENOMEM;
> + acpi_desc = acpi_nfit_desc_alloc_register(dev);
> + if (IS_ERR(acpi_desc))
> + return PTR_ERR(acpi_desc);
>
> /*
> * Save the acpi header for later and then skip it,
> @@ -2587,6 +2674,7 @@ static int acpi_nfit_remove(struct acpi_device *adev)
>
> acpi_desc->cancel = 1;
> flush_workqueue(nfit_wq);
> + sysfs_put(acpi_desc->scrub_count_state);
> nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
> return 0;
> }
> @@ -2611,13 +2699,10 @@ static void acpi_nfit_notify(struct acpi_device *adev, u32 event)
> }
>
> if (!acpi_desc) {
> - acpi_desc = devm_kzalloc(dev, sizeof(*acpi_desc), GFP_KERNEL);
> - if (!acpi_desc)
> - goto out_unlock;
> - acpi_nfit_desc_init(acpi_desc, &adev->dev);
> - acpi_desc->nvdimm_bus = nvdimm_bus_register(dev, &acpi_desc->nd_desc);
> - if (!acpi_desc->nvdimm_bus)
> - goto out_unlock;
> + acpi_desc = acpi_nfit_desc_alloc_register(dev);
> + if (IS_ERR(acpi_desc))
> + dev_err(dev, "%s: failed to alloc acpi_desc (%ld)\n",
> + __func__, PTR_ERR(acpi_desc));
> } else {
> /*
> * Finish previous registration before considering new
> diff --git a/drivers/acpi/nfit.h b/drivers/acpi/nfit.h
> index 02b9ea1..954d2aa 100644
> --- a/drivers/acpi/nfit.h
> +++ b/drivers/acpi/nfit.h
> @@ -77,7 +77,7 @@ struct nfit_spa {
> struct acpi_nfit_system_address *spa;
> struct list_head list;
> struct nd_region *nd_region;
> - unsigned int ars_done:1;
> + unsigned int ars_required:1;
> u32 clear_err_unit;
> u32 max_ars;
> };
> @@ -146,6 +146,8 @@ struct acpi_nfit_desc {
> struct nd_cmd_ars_status *ars_status;
> size_t ars_status_size;
> struct work_struct work;
> + struct kernfs_node *scrub_count_state;
> + unsigned int scrub_count;
> unsigned int cancel:1;
> unsigned long dimm_cmd_force_en;
> unsigned long bus_cmd_force_en;
> diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
> index be89764..d81db3ac 100644
> --- a/drivers/nvdimm/core.c
> +++ b/drivers/nvdimm/core.c
> @@ -99,6 +99,13 @@ struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus)
> }
> EXPORT_SYMBOL_GPL(to_nd_desc);
>
> +struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus)
> +{
> + /* struct nvdimm_bus definition is private to libnvdimm */
> + return &nvdimm_bus->dev;
> +}
> +EXPORT_SYMBOL_GPL(to_nvdimm_bus_dev);
> +
> struct nvdimm_bus *walk_to_nvdimm_bus(struct device *nd_dev)
> {
> struct device *dev;
> diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
> index 0c3c30c..27cecc2 100644
> --- a/include/linux/libnvdimm.h
> +++ b/include/linux/libnvdimm.h
> @@ -129,6 +129,7 @@ struct nvdimm *to_nvdimm(struct device *dev);
> struct nd_region *to_nd_region(struct device *dev);
> struct nd_blk_region *to_nd_blk_region(struct device *dev);
> struct nvdimm_bus_descriptor *to_nd_desc(struct nvdimm_bus *nvdimm_bus);
> +struct device *to_nvdimm_bus_dev(struct nvdimm_bus *nvdimm_bus);
> const char *nvdimm_name(struct nvdimm *nvdimm);
> unsigned long nvdimm_cmd_mask(struct nvdimm *nvdimm);
> void *nvdimm_provider_data(struct nvdimm *nvdimm);
> diff --git a/tools/testing/nvdimm/test/nfit.c b/tools/testing/nvdimm/test/nfit.c
> index c919866..74231de 100644
> --- a/tools/testing/nvdimm/test/nfit.c
> +++ b/tools/testing/nvdimm/test/nfit.c
> @@ -20,6 +20,7 @@
> #include <linux/mutex.h>
> #include <linux/ndctl.h>
> #include <linux/sizes.h>
> +#include <linux/sysfs.h>
> #include <linux/list.h>
> #include <linux/slab.h>
> #include <nfit.h>
> @@ -1409,6 +1410,8 @@ static int nfit_test_probe(struct platform_device *pdev)
> struct acpi_nfit_desc *acpi_desc;
> struct device *dev = &pdev->dev;
> struct nfit_test *nfit_test;
> + struct kernfs_node *nfit;
> + struct device *bus_dev;
> int rc;
>
> nfit_test = to_nfit_test(&pdev->dev);
> @@ -1471,6 +1474,18 @@ static int nfit_test_probe(struct platform_device *pdev)
> if (!acpi_desc->nvdimm_bus)
> return -ENXIO;
>
> + bus_dev = to_nvdimm_bus_dev(acpi_desc->nvdimm_bus);
> + nfit = sysfs_get_dirent(bus_dev->kobj.sd, "nfit");
> + if (!nfit) {
> + dev_err(dev, "sysfs_get_dirent 'nfit' failed\n");
> + return -ENODEV;
> + }
> + acpi_desc->scrub_count_state = sysfs_get_dirent(nfit, "scrub");
> + if (!acpi_desc->scrub_count_state) {
> + dev_err(dev, "sysfs_get_dirent 'scrub' failed\n");
> + return -ENODEV;
> + }
> +
> rc = acpi_nfit_init(acpi_desc, nfit_test->nfit_size);
> if (rc) {
> nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
> @@ -1497,6 +1512,7 @@ static int nfit_test_remove(struct platform_device *pdev)
> struct nfit_test *nfit_test = to_nfit_test(&pdev->dev);
> struct acpi_nfit_desc *acpi_desc = &nfit_test->acpi_desc;
>
> + sysfs_put(acpi_desc->scrub_count_state);
> nvdimm_bus_unregister(acpi_desc->nvdimm_bus);
>
> return 0;
>
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