Merge branch 'akpm' (final batch from Andrew)

Merge third patch-bumb from Andrew Morton:
 "This wraps me up for -rc1.
   - Lots of misc stuff and things which were deferred/missed from
     patchbombings 1 & 2.
   - ocfs2 things
   - lib/scatterlist
   - hfsplus
   - fatfs
   - documentation
   - signals
   - procfs
   - lockdep
   - coredump
   - seqfile core
   - kexec
   - Tejun's large IDR tree reworkings
   - ipmi
   - partitions
   - nbd
   - random() things
   - kfifo
   - tools/testing/selftests updates
   - Sasha's large and pointless hlist cleanup"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (163 commits)
  hlist: drop the node parameter from iterators
  kcmp: make it depend on CHECKPOINT_RESTORE
  selftests: add a simple doc
  tools/testing/selftests/Makefile: rearrange targets
  selftests/efivarfs: add create-read test
  selftests/efivarfs: add empty file creation test
  selftests: add tests for efivarfs
  kfifo: fix kfifo_alloc() and kfifo_init()
  kfifo: move kfifo.c from kernel/ to lib/
  arch Kconfig: centralise CONFIG_ARCH_NO_VIRT_TO_BUS
  w1: add support for DS2413 Dual Channel Addressable Switch
  memstick: move the dereference below the NULL test
  drivers/pps/clients/pps-gpio.c: use devm_kzalloc
  Documentation/DMA-API-HOWTO.txt: fix typo
  include/linux/eventfd.h: fix incorrect filename is a comment
  mtd: mtd_stresstest: use prandom_bytes()
  mtd: mtd_subpagetest: convert to use prandom library
  mtd: mtd_speedtest: use prandom_bytes
  mtd: mtd_pagetest: convert to use prandom library
  mtd: mtd_oobtest: convert to use prandom library
  ...

1 files changed, 106 insertions, 64 deletions

diff --git a/include/linux/idr.h b/include/linux/idr.h
index e5eb125effe..a6f38b5c34e 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
@@ -141,7 +183,6 @@ struct ida {
 
 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__ */