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__ */