dax: introduce dax_operations
Track a set of dax_operations per dax_device that can be set at alloc_dax() 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 device 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@lst.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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7205800541
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@ -13,7 +13,9 @@
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#ifndef __DAX_H__
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#ifndef __DAX_H__
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#define __DAX_H__
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#define __DAX_H__
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struct dax_device;
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struct dax_device;
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struct dax_device *alloc_dax(void *private, const char *host);
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struct dax_operations;
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struct dax_device *alloc_dax(void *private, const char *host,
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const struct dax_operations *ops);
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void put_dax(struct dax_device *dax_dev);
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void put_dax(struct dax_device *dax_dev);
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bool dax_alive(struct dax_device *dax_dev);
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bool dax_alive(struct dax_device *dax_dev);
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void kill_dax(struct dax_device *dax_dev);
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void kill_dax(struct dax_device *dax_dev);
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@ -645,7 +645,11 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region,
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goto err_id;
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goto err_id;
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}
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}
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dax_dev = alloc_dax(dev_dax, NULL);
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/*
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* No 'host' or dax_operations since there is no access to this
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* device outside of mmap of the resulting character device.
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*/
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dax_dev = alloc_dax(dev_dax, NULL, NULL);
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if (!dax_dev)
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if (!dax_dev)
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goto err_dax;
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goto err_dax;
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@ -17,6 +17,7 @@
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#include <linux/cdev.h>
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#include <linux/cdev.h>
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#include <linux/hash.h>
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#include <linux/hash.h>
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#include <linux/slab.h>
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#include <linux/slab.h>
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#include <linux/dax.h>
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#include <linux/fs.h>
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#include <linux/fs.h>
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static int nr_dax = CONFIG_NR_DEV_DAX;
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static int nr_dax = CONFIG_NR_DEV_DAX;
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@ -61,6 +62,7 @@ struct dax_device {
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const char *host;
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const char *host;
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void *private;
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void *private;
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bool alive;
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bool alive;
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const struct dax_operations *ops;
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};
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};
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bool dax_alive(struct dax_device *dax_dev)
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bool dax_alive(struct dax_device *dax_dev)
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@ -208,7 +210,8 @@ static void dax_add_host(struct dax_device *dax_dev, const char *host)
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spin_unlock(&dax_host_lock);
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spin_unlock(&dax_host_lock);
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}
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}
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struct dax_device *alloc_dax(void *private, const char *__host)
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struct dax_device *alloc_dax(void *private, const char *__host,
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const struct dax_operations *ops)
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{
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{
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struct dax_device *dax_dev;
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struct dax_device *dax_dev;
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const char *host;
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const char *host;
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@ -229,6 +232,7 @@ struct dax_device *alloc_dax(void *private, const char *__host)
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goto err_dev;
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goto err_dev;
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dax_add_host(dax_dev, host);
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dax_add_host(dax_dev, host);
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dax_dev->ops = ops;
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dax_dev->private = private;
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dax_dev->private = private;
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return dax_dev;
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return dax_dev;
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@ -7,6 +7,16 @@
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#include <asm/pgtable.h>
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#include <asm/pgtable.h>
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struct iomap_ops;
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struct iomap_ops;
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struct dax_device;
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struct dax_operations {
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/*
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* direct_access: translate a device-relative
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* logical-page-offset into an absolute physical pfn. Return the
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* number of pages available for DAX at that pfn.
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*/
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long (*direct_access)(struct dax_device *, pgoff_t, long,
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void **, pfn_t *);
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};
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int dax_read_lock(void);
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int dax_read_lock(void);
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void dax_read_unlock(int id);
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void dax_read_unlock(int id);
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