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xarray: Add definition of struct xarray

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This is a direct replacement for struct radix_tree_root.  Some of the
struct members have changed name; convert those, and use a #define so
that radix_tree users continue to work without change.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Josef Bacik <jbacik@fb.com>
This commit is contained in:
Matthew Wilcox
2017-11-07 16:30:10 -05:00
parent 02c02bf12c
commit f8d5d0cc14
12 changed files with 181 additions and 68 deletions
Download Patch File Download Diff File Expand all files Collapse all files

28
include/linux/radix-tree.h
View File

@@ -30,6 +30,9 @@
#include <linux/types.h>
#include <linux/xarray.h>
/* Keep unconverted code working */
#define radix_tree_root xarray
/*
* The bottom two bits of the slot determine how the remaining bits in the
* slot are interpreted:
@@ -92,36 +95,21 @@ struct radix_tree_node {
unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
};
/* The IDR tag is stored in the low bits of the GFP flags */
/* The IDR tag is stored in the low bits of xa_flags */
#define ROOT_IS_IDR ((__force gfp_t)4)
/* The top bits of gfp_mask are used to store the root tags */
/* The top bits of xa_flags are used to store the root tags */
#define ROOT_TAG_SHIFT (__GFP_BITS_SHIFT)
struct radix_tree_root {
spinlock_t xa_lock;
gfp_t gfp_mask;
struct radix_tree_node __rcu *rnode;
};
#define RADIX_TREE_INIT(name, mask) { \
.xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \
.gfp_mask = (mask), \
.rnode = NULL, \
}
#define RADIX_TREE_INIT(name, mask) XARRAY_INIT(name, mask)
#define RADIX_TREE(name, mask) \
struct radix_tree_root name = RADIX_TREE_INIT(name, mask)
#define INIT_RADIX_TREE(root, mask) \
do { \
spin_lock_init(&(root)->xa_lock); \
(root)->gfp_mask = (mask); \
(root)->rnode = NULL; \
} while (0)
#define INIT_RADIX_TREE(root, mask) xa_init_flags(root, mask)
static inline bool radix_tree_empty(const struct radix_tree_root *root)
{
return root->rnode == NULL;
return root->xa_head == NULL;
}
/**

70
include/linux/xarray.h
View File

@@ -10,6 +10,8 @@
*/
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/kconfig.h>
#include <linux/spinlock.h>
#include <linux/types.h>
@@ -153,6 +155,74 @@ static inline bool xa_is_internal(const void *entry)
return ((unsigned long)entry & 3) == 2;
}
/**
* struct xarray - The anchor of the XArray.
* @xa_lock: Lock that protects the contents of the XArray.
*
* To use the xarray, define it statically or embed it in your data structure.
* It is a very small data structure, so it does not usually make sense to
* allocate it separately and keep a pointer to it in your data structure.
*
* You may use the xa_lock to protect your own data structures as well.
*/
/*
* If all of the entries in the array are NULL, @xa_head is a NULL pointer.
* If the only non-NULL entry in the array is at index 0, @xa_head is that
* entry. If any other entry in the array is non-NULL, @xa_head points
* to an @xa_node.
*/
struct xarray {
spinlock_t xa_lock;
/* private: The rest of the data structure is not to be used directly. */
gfp_t xa_flags;
void __rcu * xa_head;
};
#define XARRAY_INIT(name, flags) { \
.xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \
.xa_flags = flags, \
.xa_head = NULL, \
}
/**
* DEFINE_XARRAY_FLAGS() - Define an XArray with custom flags.
* @name: A string that names your XArray.
* @flags: XA_FLAG values.
*
* This is intended for file scope definitions of XArrays. It declares
* and initialises an empty XArray with the chosen name and flags. It is
* equivalent to calling xa_init_flags() on the array, but it does the
* initialisation at compiletime instead of runtime.
*/
#define DEFINE_XARRAY_FLAGS(name, flags) \
struct xarray name = XARRAY_INIT(name, flags)
/**
* DEFINE_XARRAY() - Define an XArray.
* @name: A string that names your XArray.
*
* This is intended for file scope definitions of XArrays. It declares
* and initialises an empty XArray with the chosen name. It is equivalent
* to calling xa_init() on the array, but it does the initialisation at
* compiletime instead of runtime.
*/
#define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0)
void xa_init_flags(struct xarray *, gfp_t flags);
/**
* xa_init() - Initialise an empty XArray.
* @xa: XArray.
*
* An empty XArray is full of NULL entries.
*
* Context: Any context.
*/
static inline void xa_init(struct xarray *xa)
{
xa_init_flags(xa, 0);
}
#define xa_trylock(xa) spin_trylock(&(xa)->xa_lock)
#define xa_lock(xa) spin_lock(&(xa)->xa_lock)
#define xa_unlock(xa) spin_unlock(&(xa)->xa_lock)