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-rw-r--r--include/linux/idr.h172
1 files changed, 107 insertions, 65 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h
index de7e190f1af4..a6f38b5c34e4 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -17,69 +17,40 @@
#include <linux/init.h>
#include <linux/rcupdate.h>
-#if BITS_PER_LONG == 32
-# define IDR_BITS 5
-# define IDR_FULL 0xfffffffful
-/* We can only use two of the bits in the top level because there is
- only one possible bit in the top level (5 bits * 7 levels = 35
- bits, but you only use 31 bits in the id). */
-# define TOP_LEVEL_FULL (IDR_FULL >> 30)
-#elif BITS_PER_LONG == 64
-# define IDR_BITS 6
-# define IDR_FULL 0xfffffffffffffffful
-/* We can only use two of the bits in the top level because there is
- only one possible bit in the top level (6 bits * 6 levels = 36
- bits, but you only use 31 bits in the id). */
-# define TOP_LEVEL_FULL (IDR_FULL >> 62)
-#else
-# error "BITS_PER_LONG is not 32 or 64"
-#endif
-
+/*
+ * We want shallower trees and thus more bits covered at each layer. 8
+ * bits gives us large enough first layer for most use cases and maximum
+ * tree depth of 4. Each idr_layer is slightly larger than 2k on 64bit and
+ * 1k on 32bit.
+ */
+#define IDR_BITS 8
#define IDR_SIZE (1 << IDR_BITS)
#define IDR_MASK ((1 << IDR_BITS)-1)
-#define MAX_IDR_SHIFT (sizeof(int)*8 - 1)
-#define MAX_IDR_BIT (1U << MAX_IDR_SHIFT)
-#define MAX_IDR_MASK (MAX_IDR_BIT - 1)
-
-/* Leave the possibility of an incomplete final layer */
-#define MAX_IDR_LEVEL ((MAX_IDR_SHIFT + IDR_BITS - 1) / IDR_BITS)
-
-/* Number of id_layer structs to leave in free list */
-#define MAX_IDR_FREE (MAX_IDR_LEVEL * 2)
-
struct idr_layer {
- unsigned long bitmap; /* A zero bit means "space here" */
+ int prefix; /* the ID prefix of this idr_layer */
+ DECLARE_BITMAP(bitmap, IDR_SIZE); /* A zero bit means "space here" */
struct idr_layer __rcu *ary[1<<IDR_BITS];
- int count; /* When zero, we can release it */
- int layer; /* distance from leaf */
- struct rcu_head rcu_head;
+ int count; /* When zero, we can release it */
+ int layer; /* distance from leaf */
+ struct rcu_head rcu_head;
};
struct idr {
- struct idr_layer __rcu *top;
- struct idr_layer *id_free;
- int layers; /* only valid without concurrent changes */
- int id_free_cnt;
- spinlock_t lock;
+ struct idr_layer __rcu *hint; /* the last layer allocated from */
+ struct idr_layer __rcu *top;
+ struct idr_layer *id_free;
+ int layers; /* only valid w/o concurrent changes */
+ int id_free_cnt;
+ spinlock_t lock;
};
-#define IDR_INIT(name) \
-{ \
- .top = NULL, \
- .id_free = NULL, \
- .layers = 0, \
- .id_free_cnt = 0, \
- .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
+#define IDR_INIT(name) \
+{ \
+ .lock = __SPIN_LOCK_UNLOCKED(name.lock), \
}
#define DEFINE_IDR(name) struct idr name = IDR_INIT(name)
-/* Actions to be taken after a call to _idr_sub_alloc */
-#define IDR_NEED_TO_GROW -2
-#define IDR_NOMORE_SPACE -3
-
-#define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC)
-
/**
* DOC: idr sync
* idr synchronization (stolen from radix-tree.h)
@@ -101,19 +72,90 @@ struct idr {
* This is what we export.
*/
-void *idr_find(struct idr *idp, int id);
+void *idr_find_slowpath(struct idr *idp, int id);
int idr_pre_get(struct idr *idp, gfp_t gfp_mask);
-int idr_get_new(struct idr *idp, void *ptr, int *id);
int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id);
+void idr_preload(gfp_t gfp_mask);
+int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask);
int idr_for_each(struct idr *idp,
int (*fn)(int id, void *p, void *data), void *data);
void *idr_get_next(struct idr *idp, int *nextid);
void *idr_replace(struct idr *idp, void *ptr, int id);
void idr_remove(struct idr *idp, int id);
-void idr_remove_all(struct idr *idp);
+void idr_free(struct idr *idp, int id);
void idr_destroy(struct idr *idp);
void idr_init(struct idr *idp);
+/**
+ * idr_preload_end - end preload section started with idr_preload()
+ *
+ * Each idr_preload() should be matched with an invocation of this
+ * function. See idr_preload() for details.
+ */
+static inline void idr_preload_end(void)
+{
+ preempt_enable();
+}
+
+/**
+ * idr_find - return pointer for given id
+ * @idp: idr handle
+ * @id: lookup key
+ *
+ * Return the pointer given the id it has been registered with. A %NULL
+ * return indicates that @id is not valid or you passed %NULL in
+ * idr_get_new().
+ *
+ * This function can be called under rcu_read_lock(), given that the leaf
+ * pointers lifetimes are correctly managed.
+ */
+static inline void *idr_find(struct idr *idr, int id)
+{
+ struct idr_layer *hint = rcu_dereference_raw(idr->hint);
+
+ if (hint && (id & ~IDR_MASK) == hint->prefix)
+ return rcu_dereference_raw(hint->ary[id & IDR_MASK]);
+
+ return idr_find_slowpath(idr, id);
+}
+
+/**
+ * idr_get_new - allocate new idr entry
+ * @idp: idr handle
+ * @ptr: pointer you want associated with the id
+ * @id: pointer to the allocated handle
+ *
+ * Simple wrapper around idr_get_new_above() w/ @starting_id of zero.
+ */
+static inline int idr_get_new(struct idr *idp, void *ptr, int *id)
+{
+ return idr_get_new_above(idp, ptr, 0, id);
+}
+
+/**
+ * idr_for_each_entry - iterate over an idr's elements of a given type
+ * @idp: idr handle
+ * @entry: the type * to use as cursor
+ * @id: id entry's key
+ */
+#define idr_for_each_entry(idp, entry, id) \
+ for (id = 0, entry = (typeof(entry))idr_get_next((idp), &(id)); \
+ entry != NULL; \
+ ++id, entry = (typeof(entry))idr_get_next((idp), &(id)))
+
+void __idr_remove_all(struct idr *idp); /* don't use */
+
+/**
+ * idr_remove_all - remove all ids from the given idr tree
+ * @idp: idr handle
+ *
+ * If you're trying to destroy @idp, calling idr_destroy() is enough.
+ * This is going away. Don't use.
+ */
+static inline void __deprecated idr_remove_all(struct idr *idp)
+{
+ __idr_remove_all(idp);
+}
/*
* IDA - IDR based id allocator, use when translation from id to
@@ -136,12 +178,11 @@ struct ida {
struct ida_bitmap *free_bitmap;
};
-#define IDA_INIT(name) { .idr = IDR_INIT(name), .free_bitmap = NULL, }
+#define IDA_INIT(name) { .idr = IDR_INIT((name).idr), .free_bitmap = NULL, }
#define DEFINE_IDA(name) struct ida name = IDA_INIT(name)
int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
-int ida_get_new(struct ida *ida, int *p_id);
void ida_remove(struct ida *ida, int id);
void ida_destroy(struct ida *ida);
void ida_init(struct ida *ida);
@@ -150,17 +191,18 @@ int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
gfp_t gfp_mask);
void ida_simple_remove(struct ida *ida, unsigned int id);
-void __init idr_init_cache(void);
-
/**
- * idr_for_each_entry - iterate over an idr's elements of a given type
- * @idp: idr handle
- * @entry: the type * to use as cursor
- * @id: id entry's key
+ * ida_get_new - allocate new ID
+ * @ida: idr handle
+ * @p_id: pointer to the allocated handle
+ *
+ * Simple wrapper around ida_get_new_above() w/ @starting_id of zero.
*/
-#define idr_for_each_entry(idp, entry, id) \
- for (id = 0, entry = (typeof(entry))idr_get_next((idp), &(id)); \
- entry != NULL; \
- ++id, entry = (typeof(entry))idr_get_next((idp), &(id)))
+static inline int ida_get_new(struct ida *ida, int *p_id)
+{
+ return ida_get_new_above(ida, 0, p_id);
+}
+
+void __init idr_init_cache(void);
#endif /* __IDR_H__ */
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 14:45:16 +0000