From 6568b08b77816cda2a95919c7494108d983d5941 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 24 Jan 2017 18:44:18 -0800 Subject: [PATCH] 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 Signed-off-by: Dan Williams --- drivers/dax/dax.h | 4 +++- drivers/dax/device.c | 6 +++++- drivers/dax/super.c | 6 +++++- include/linux/dax.h | 10 ++++++++++ 4 files changed, 23 insertions(+), 3 deletions(-) diff --git a/drivers/dax/dax.h b/drivers/dax/dax.h index 246a24d68d4c..617bbc24be2b 100644 --- a/drivers/dax/dax.h +++ b/drivers/dax/dax.h @@ -13,7 +13,9 @@ #ifndef __DAX_H__ #define __DAX_H__ struct dax_device; -struct dax_device *alloc_dax(void *private, const char *host); +struct dax_operations; +struct dax_device *alloc_dax(void *private, const char *host, + const struct dax_operations *ops); void put_dax(struct dax_device *dax_dev); bool dax_alive(struct dax_device *dax_dev); void kill_dax(struct dax_device *dax_dev); diff --git a/drivers/dax/device.c b/drivers/dax/device.c index db68f4fa8ce0..a0db055054a4 100644 --- a/drivers/dax/device.c +++ b/drivers/dax/device.c @@ -645,7 +645,11 @@ struct dev_dax *devm_create_dev_dax(struct dax_region *dax_region, goto err_id; } - dax_dev = alloc_dax(dev_dax, NULL); + /* + * 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); if (!dax_dev) goto err_dax; diff --git a/drivers/dax/super.c b/drivers/dax/super.c index 8d446674c1da..1a58542ee8fd 100644 --- a/drivers/dax/super.c +++ b/drivers/dax/super.c @@ -17,6 +17,7 @@ #include #include #include +#include #include static int nr_dax = CONFIG_NR_DEV_DAX; @@ -61,6 +62,7 @@ struct dax_device { const char *host; void *private; bool alive; + const struct dax_operations *ops; }; bool dax_alive(struct dax_device *dax_dev) @@ -208,7 +210,8 @@ static void dax_add_host(struct dax_device *dax_dev, const char *host) spin_unlock(&dax_host_lock); } -struct dax_device *alloc_dax(void *private, const char *__host) +struct dax_device *alloc_dax(void *private, const char *__host, + const struct dax_operations *ops) { struct dax_device *dax_dev; const char *host; @@ -229,6 +232,7 @@ struct dax_device *alloc_dax(void *private, const char *__host) goto err_dev; dax_add_host(dax_dev, host); + dax_dev->ops = ops; dax_dev->private = private; return dax_dev; diff --git a/include/linux/dax.h b/include/linux/dax.h index 9b2d5ba10d7d..74ebb92b625a 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -7,6 +7,16 @@ #include struct iomap_ops; +struct dax_device; +struct dax_operations { + /* + * direct_access: translate a device-relative + * logical-page-offset into an absolute physical pfn. Return the + * number of pages available for DAX at that pfn. + */ + long (*direct_access)(struct dax_device *, pgoff_t, long, + void **, pfn_t *); +}; int dax_read_lock(void); void dax_read_unlock(int id); -- 2.20.1