libnvdimm: infrastructure for btt devices
NVDIMM namespaces, in addition to accepting "struct bio" based requests,
also have the capability to perform byte-aligned accesses. By default
only the bio/block interface is used. However, if another driver can
make effective use of the byte-aligned capability it can claim namespace
interface and use the byte-aligned ->rw_bytes() interface.
The BTT driver is the initial first consumer of this mechanism to allow
adding atomic sector update semantics to a pmem or blk namespace. This
patch is the sysfs infrastructure to allow configuring a BTT instance
for a namespace. Enabling that BTT and performing i/o is in a
subsequent patch.
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/include/linux/nd.h b/include/linux/nd.h
index 23276ea..507e47c 100644
--- a/include/linux/nd.h
+++ b/include/linux/nd.h
@@ -12,6 +12,7 @@
*/
#ifndef __LINUX_ND_H__
#define __LINUX_ND_H__
+#include <linux/fs.h>
#include <linux/ndctl.h>
#include <linux/device.h>
@@ -29,12 +30,32 @@
};
/**
+ * struct nd_namespace_common - core infrastructure of a namespace
+ * @force_raw: ignore other personalities for the namespace (e.g. btt)
+ * @dev: device model node
+ * @claim: when set a another personality has taken ownership of the namespace
+ * @rw_bytes: access the raw namespace capacity with byte-aligned transfers
+ */
+struct nd_namespace_common {
+ int force_raw;
+ struct device dev;
+ struct device *claim;
+ int (*rw_bytes)(struct nd_namespace_common *, resource_size_t offset,
+ void *buf, size_t size, int rw);
+};
+
+static inline struct nd_namespace_common *to_ndns(struct device *dev)
+{
+ return container_of(dev, struct nd_namespace_common, dev);
+}
+
+/**
* struct nd_namespace_io - infrastructure for loading an nd_pmem instance
* @dev: namespace device created by the nd region driver
* @res: struct resource conversion of a NFIT SPA table
*/
struct nd_namespace_io {
- struct device dev;
+ struct nd_namespace_common common;
struct resource res;
};
@@ -52,7 +73,6 @@
/**
* struct nd_namespace_blk - namespace for dimm-bounded persistent memory
- * @dev: namespace device creation by the nd region driver
* @alt_name: namespace name supplied in the dimm label
* @uuid: namespace name supplied in the dimm label
* @id: ida allocated id
@@ -61,7 +81,7 @@
* @res: discontiguous dpa extents for given dimm
*/
struct nd_namespace_blk {
- struct device dev;
+ struct nd_namespace_common common;
char *alt_name;
u8 *uuid;
int id;
@@ -72,7 +92,7 @@
static inline struct nd_namespace_io *to_nd_namespace_io(struct device *dev)
{
- return container_of(dev, struct nd_namespace_io, dev);
+ return container_of(dev, struct nd_namespace_io, common.dev);
}
static inline struct nd_namespace_pmem *to_nd_namespace_pmem(struct device *dev)
@@ -84,7 +104,40 @@
static inline struct nd_namespace_blk *to_nd_namespace_blk(struct device *dev)
{
- return container_of(dev, struct nd_namespace_blk, dev);
+ return container_of(dev, struct nd_namespace_blk, common.dev);
+}
+
+/**
+ * nvdimm_read_bytes() - synchronously read bytes from an nvdimm namespace
+ * @ndns: device to read
+ * @offset: namespace-relative starting offset
+ * @buf: buffer to fill
+ * @size: transfer length
+ *
+ * @buf is up-to-date upon return from this routine.
+ */
+static inline int nvdimm_read_bytes(struct nd_namespace_common *ndns,
+ resource_size_t offset, void *buf, size_t size)
+{
+ return ndns->rw_bytes(ndns, offset, buf, size, READ);
+}
+
+/**
+ * nvdimm_write_bytes() - synchronously write bytes to an nvdimm namespace
+ * @ndns: device to read
+ * @offset: namespace-relative starting offset
+ * @buf: buffer to drain
+ * @size: transfer length
+ *
+ * NVDIMM Namepaces disks do not implement sectors internally. Depending on
+ * the @ndns, the contents of @buf may be in cpu cache, platform buffers,
+ * or on backing memory media upon return from this routine. Flushing
+ * to media is handled internal to the @ndns driver, if at all.
+ */
+static inline int nvdimm_write_bytes(struct nd_namespace_common *ndns,
+ resource_size_t offset, void *buf, size_t size)
+{
+ return ndns->rw_bytes(ndns, offset, buf, size, WRITE);
}
#define MODULE_ALIAS_ND_DEVICE(type) \