Track a set of dax_operations per dax_inode that can be set at
alloc_dax_inode() time. These operations will be used to stop the abuse
of block_device_operations for communicating dax capabilities to
filesystems. It will also be used to replace the "pmem api" and move
pmem-specific cache maintenance, and other dax-driver-specific
filesystem-dax operations, to dax inode methods. In particular this
allows us to stop abusing __copy_user_nocache(), via memcpy_to_pmem(),
with a driver specific replacement.
This is a standalone introduction of the operations. Follow on patches
convert each dax-driver and teach fs/dax.c to use ->direct_access() from
dax_operations instead of block_device_operations.
Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
drivers/dax/dax.h | 4 +++-
drivers/dax/device.c | 6 +++++-
drivers/dax/super.c | 6 +++++-
include/linux/dax.h | 5 +++++
4 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h
index f33c16ed2ec6..aeb1d49aafb8 100644
--- a/drivers/dax/dax.h
+++ b/drivers/dax/dax.h
@@ -13,7 +13,9 @@
#ifndef __DAX_H__
#define __DAX_H__
struct dax_inode;
-struct dax_inode *alloc_dax_inode(void *private, const char *host);
+struct dax_operations;
+struct dax_inode *alloc_dax_inode(void *private, const char *host,
+ const struct dax_operations *ops);
void put_dax_inode(struct dax_inode *dax_inode);
bool dax_inode_alive(struct dax_inode *dax_inode);
void kill_dax_inode(struct dax_inode *dax_inode);
diff --git a/drivers/dax/device.c b/drivers/dax/device.c
index 6d0a3241a608..c3d9405ec285 100644
--- a/drivers/dax/device.c
+++ b/drivers/dax/device.c
@@ -560,7 +560,11 @@ struct dax_dev *devm_create_dax_dev(struct dax_region *dax_region,
goto err_id;
}
- dax_inode = alloc_dax_inode(dax_dev, NULL);
+ /*
+ * No 'host' or dax_operations since there is no access to this
+ * device outside of mmap of the resulting character device.
+ */
+ dax_inode = alloc_dax_inode(dax_dev, NULL, NULL);
if (!dax_inode)
goto err_inode;
diff --git a/drivers/dax/super.c b/drivers/dax/super.c
index 7ac048f94b2b..eb844ffea3cf 100644
--- a/drivers/dax/super.c
+++ b/drivers/dax/super.c
@@ -17,6 +17,7 @@
#include <linux/cdev.h>
#include <linux/hash.h>
#include <linux/slab.h>
+#include <linux/dax.h>
#include <linux/fs.h>
static int nr_dax = CONFIG_NR_DEV_DAX;
@@ -61,6 +62,7 @@ struct dax_inode {
const char *host;
void *private;
bool alive;
+ const struct dax_operations *ops;
};
bool dax_inode_alive(struct dax_inode *dax_inode)
@@ -204,7 +206,8 @@ static void dax_add_host(struct dax_inode *dax_inode, const char *host)
spin_unlock(&dax_host_lock);
}
-struct dax_inode *alloc_dax_inode(void *private, const char *__host)
+struct dax_inode *alloc_dax_inode(void *private, const char *__host,
+ const struct dax_operations *ops)
{
struct dax_inode *dax_inode;
const char *host;
@@ -225,6 +228,7 @@ struct dax_inode *alloc_dax_inode(void *private, const char *__host)
goto err_inode;
dax_add_host(dax_inode, host);
+ dax_inode->ops = ops;
dax_inode->private = private;
return dax_inode;
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 8fe19230e118..def9a9d118c9 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -7,6 +7,11 @@
#include <asm/pgtable.h>
struct iomap_ops;
+struct dax_inode;
+struct dax_operations {
+ long (*direct_access)(struct dax_inode *, phys_addr_t, void **,
+ pfn_t *, long);
+};
int dax_read_lock(void);
void dax_read_unlock(int id);
--
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