[RFC PATCH v2 3/5] libnvdimm/dax: Make DAXDEV_SYNC_ENABLED flag region-specific
Aneesh Kumar K.V
aneesh.kumar at linux.ibm.com
Tue Jun 2 17:49:07 AEST 2020
This patch makes sync fault enable/disable feature more fine-grained
by allowing region-wise control of the same.
In a followup patch on ppc64 only device with compat string "ibm,pmemory-v2"
will disable the sync fault feature.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar at linux.ibm.com>
---
drivers/dax/bus.c | 2 +-
drivers/dax/super.c | 16 +++++++++-------
drivers/nvdimm/pmem.c | 4 ++++
drivers/nvdimm/region_devs.c | 16 ++++++++++++++++
include/linux/dax.h | 16 ++++++++++++++++
include/linux/libnvdimm.h | 4 ++++
6 files changed, 50 insertions(+), 8 deletions(-)
diff --git a/drivers/dax/bus.c b/drivers/dax/bus.c
index df238c8b6ef2..8a825ecff49b 100644
--- a/drivers/dax/bus.c
+++ b/drivers/dax/bus.c
@@ -420,7 +420,7 @@ struct dev_dax *__devm_create_dev_dax(struct dax_region *dax_region, int id,
* No 'host' or dax_operations since there is no access to this
* device outside of mmap of the resulting character device.
*/
- dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC);
+ dax_dev = alloc_dax(dev_dax, NULL, NULL, DAXDEV_F_SYNC | DAXDEV_F_SYNC_ENABLED);
if (IS_ERR(dax_dev)) {
rc = PTR_ERR(dax_dev);
goto err;
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 980f7be7e56d..f93e6649d452 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -260,10 +260,11 @@ static ssize_t write_cache_store(struct device *dev,
}
static DEVICE_ATTR_RW(write_cache);
-static bool dax_synchronous_enabled(struct dax_device *dax_dev)
+bool __dax_synchronous_enabled(struct dax_device *dax_dev)
{
return test_bit(DAXDEV_SYNC_ENABLED, &dax_dev->flags);
}
+EXPORT_SYMBOL_GPL(__dax_synchronous_enabled);
static void set_dax_synchronous_enable(struct dax_device *dax_dev, bool enable)
{
@@ -280,6 +281,7 @@ static void set_dax_synchronous_enable(struct dax_device *dax_dev, bool enable)
static ssize_t sync_fault_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
+ int enabled;
struct dax_device *dax_dev = dax_get_by_host(dev_name(dev));
ssize_t rc;
@@ -287,7 +289,8 @@ static ssize_t sync_fault_show(struct device *dev,
if (!dax_dev)
return -ENXIO;
- rc = sprintf(buf, "%d\n", !!__dax_synchronous(dax_dev));
+ enabled = (dax_synchronous(dax_dev) && dax_synchronous_enabled(dax_dev));
+ rc = sprintf(buf, "%d\n", enabled);
put_dax(dax_dev);
return rc;
}
@@ -461,17 +464,13 @@ EXPORT_SYMBOL_GPL(dax_write_cache_enabled);
bool __dax_synchronous(struct dax_device *dax_dev)
{
- return test_bit(DAXDEV_SYNC, &dax_dev->flags) &&
- test_bit(DAXDEV_SYNC_ENABLED, &dax_dev->flags);
+ return test_bit(DAXDEV_SYNC, &dax_dev->flags);
}
EXPORT_SYMBOL_GPL(__dax_synchronous);
void __set_dax_synchronous(struct dax_device *dax_dev)
{
set_bit(DAXDEV_SYNC, &dax_dev->flags);
-#ifndef CONFIG_ARCH_MAP_SYNC_DISABLE
- set_bit(DAXDEV_SYNC_ENABLED, &dax_dev->flags);
-#endif
}
EXPORT_SYMBOL_GPL(__set_dax_synchronous);
@@ -665,6 +664,9 @@ struct dax_device *alloc_dax(void *private, const char *__host,
if (flags & DAXDEV_F_SYNC)
set_dax_synchronous(dax_dev);
+ if (flags & DAXDEV_F_SYNC_ENABLED)
+ set_dax_synchronous_enable(dax_dev, true);
+
return dax_dev;
err_dev:
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 2df6994acf83..dc9c269eb50d 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -485,6 +485,10 @@ static int pmem_attach_disk(struct device *dev,
if (is_nvdimm_sync(nd_region))
flags = DAXDEV_F_SYNC;
+
+ if (is_nvdimm_sync_enabled(nd_region))
+ flags |= DAXDEV_F_SYNC_ENABLED;
+
dax_dev = alloc_dax(pmem, disk->disk_name, &pmem_dax_ops, flags);
if (IS_ERR(dax_dev)) {
put_disk(disk);
diff --git a/drivers/nvdimm/region_devs.c b/drivers/nvdimm/region_devs.c
index ccbb5b43b8b2..2181560cf655 100644
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -1283,6 +1283,22 @@ bool is_nvdimm_sync(struct nd_region *nd_region)
}
EXPORT_SYMBOL_GPL(is_nvdimm_sync);
+bool is_nvdimm_sync_enabled(struct nd_region *nd_region)
+{
+#ifdef CONFIG_ARCH_MAP_SYNC_DISABLE
+ if (is_nd_volatile(&nd_region->dev))
+ return true;
+
+ return is_nd_pmem(&nd_region->dev) &&
+ test_bit(ND_REGION_SYNC_ENABLED, &nd_region->flags);
+#else
+ return true;
+#endif
+
+}
+EXPORT_SYMBOL_GPL(is_nvdimm_sync_enabled);
+
+
struct conflict_context {
struct nd_region *nd_region;
resource_size_t start, size;
diff --git a/include/linux/dax.h b/include/linux/dax.h
index d7af5d243f24..c4a3551557de 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -10,6 +10,9 @@
/* Flag for synchronous flush */
#define DAXDEV_F_SYNC (1UL << 0)
+/* flag for platform forcing synchronous flush disable */
+#define DAXDEV_F_SYNC_ENABLED (1UL << 1)
+
typedef unsigned long dax_entry_t;
struct iomap_ops;
@@ -59,6 +62,13 @@ static inline void set_dax_synchronous(struct dax_device *dax_dev)
{
__set_dax_synchronous(dax_dev);
}
+
+bool __dax_synchronous_enabled(struct dax_device *dax_dev);
+static inline bool dax_synchronous_enabled(struct dax_device *dax_dev)
+{
+ return __dax_synchronous_enabled(dax_dev);
+}
+
/*
* Check if given mapping is supported by the file / underlying device.
*/
@@ -69,6 +79,12 @@ static inline bool daxdev_mapping_supported(struct vm_area_struct *vma,
return true;
if (!IS_DAX(file_inode(vma->vm_file)))
return false;
+ /*
+ * check MAP_SYNC is disabled by platform for this device.
+ */
+ if (!dax_synchronous_enabled(dax_dev))
+ return false;
+
return dax_synchronous(dax_dev);
}
#else
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index 18da4059be09..cc3962c4978f 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -63,6 +63,9 @@ enum {
/* Platform provides asynchronous flush mechanism */
ND_REGION_ASYNC = 3,
+ /* Platform wants to disable synchronous flush mechanism */
+ ND_REGION_SYNC_ENABLED= 4,
+
/* mark newly adjusted resources as requiring a label update */
DPA_RESOURCE_ADJUSTED = 1 << 0,
};
@@ -262,6 +265,7 @@ int nvdimm_has_flush(struct nd_region *nd_region);
int nvdimm_has_cache(struct nd_region *nd_region);
int nvdimm_in_overwrite(struct nvdimm *nvdimm);
bool is_nvdimm_sync(struct nd_region *nd_region);
+bool is_nvdimm_sync_enabled(struct nd_region *nd_region);
static inline int nvdimm_ctl(struct nvdimm *nvdimm, unsigned int cmd, void *buf,
unsigned int buf_len, int *cmd_rc)
--
2.26.2
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