Merge branch 'for-4.12/asus' into for-linus

1 files changed, 533 insertions, 229 deletions

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 84812a9fb16f..691a9ad48497 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -22,20 +22,21 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/idr.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
-#include <linux/export.h>
-#include <linux/radix-tree.h>
+#include <linux/kmemleak.h>
 #include <linux/percpu.h>
+#include <linux/preempt.h>              /* in_interrupt() */
+#include <linux/radix-tree.h>
+#include <linux/rcupdate.h>
 #include <linux/slab.h>
-#include <linux/kmemleak.h>
-#include <linux/cpu.h>
 #include <linux/string.h>
-#include <linux/bitops.h>
-#include <linux/rcupdate.h>
-#include <linux/preempt.h>              /* in_interrupt() */
 
 
 /* Number of nodes in fully populated tree of given height */
@@ -60,11 +61,28 @@ static struct kmem_cache *radix_tree_node_cachep;
 #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
 
 /*
+ * The IDR does not have to be as high as the radix tree since it uses
+ * signed integers, not unsigned longs.
+ */
+#define IDR_INDEX_BITS          (8 /* CHAR_BIT */ * sizeof(int) - 1)
+#define IDR_MAX_PATH            (DIV_ROUND_UP(IDR_INDEX_BITS, \
+                                                RADIX_TREE_MAP_SHIFT))
+#define IDR_PRELOAD_SIZE        (IDR_MAX_PATH * 2 - 1)
+
+/*
+ * The IDA is even shorter since it uses a bitmap at the last level.
+ */
+#define IDA_INDEX_BITS          (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS))
+#define IDA_MAX_PATH            (DIV_ROUND_UP(IDA_INDEX_BITS, \
+                                                RADIX_TREE_MAP_SHIFT))
+#define IDA_PRELOAD_SIZE        (IDA_MAX_PATH * 2 - 1)
+
+/*
  * Per-cpu pool of preloaded nodes
  */
 struct radix_tree_preload {
         unsigned nr;
-        /* nodes->private_data points to next preallocated node */
+        /* nodes->parent points to next preallocated node */
         struct radix_tree_node *nodes;
 };
 static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
@@ -83,35 +101,38 @@ static inline void *node_to_entry(void *ptr)
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
 /* Sibling slots point directly to another slot in the same node */
-static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node)
+static inline
+bool is_sibling_entry(const struct radix_tree_node *parent, void *node)
 {
-        void **ptr = node;
+        void __rcu **ptr = node;
         return (parent->slots <= ptr) &&
                         (ptr < parent->slots + RADIX_TREE_MAP_SIZE);
 }
 #else
-static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node)
+static inline
+bool is_sibling_entry(const struct radix_tree_node *parent, void *node)
 {
         return false;
 }
 #endif
 
-static inline unsigned long get_slot_offset(struct radix_tree_node *parent,
-                                                 void **slot)
+static inline unsigned long
+get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot)
 {
         return slot - parent->slots;
 }
 
-static unsigned int radix_tree_descend(struct radix_tree_node *parent,
+static unsigned int radix_tree_descend(const struct radix_tree_node *parent,
                         struct radix_tree_node **nodep, unsigned long index)
 {
         unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
-        void **entry = rcu_dereference_raw(parent->slots[offset]);
+        void __rcu **entry = rcu_dereference_raw(parent->slots[offset]);
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
         if (radix_tree_is_internal_node(entry)) {
                 if (is_sibling_entry(parent, entry)) {
-                        void **sibentry = (void **) entry_to_node(entry);
+                        void __rcu **sibentry;
+                        sibentry = (void __rcu **) entry_to_node(entry);
                         offset = get_slot_offset(parent, sibentry);
                         entry = rcu_dereference_raw(*sibentry);
                 }
@@ -122,7 +143,7 @@ static unsigned int radix_tree_descend(struct radix_tree_node *parent,
         return offset;
 }
 
-static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
+static inline gfp_t root_gfp_mask(const struct radix_tree_root *root)
 {
         return root->gfp_mask & __GFP_BITS_MASK;
 }
@@ -139,42 +160,48 @@ static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
         __clear_bit(offset, node->tags[tag]);
 }
 
-static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
+static inline int tag_get(const struct radix_tree_node *node, unsigned int tag,
                 int offset)
 {
         return test_bit(offset, node->tags[tag]);
 }
 
-static inline void root_tag_set(struct radix_tree_root *root, unsigned int tag)
+static inline void root_tag_set(struct radix_tree_root *root, unsigned tag)
 {
-        root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
+        root->gfp_mask |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT));
 }
 
 static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag)
 {
-        root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
+        root->gfp_mask &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT));
 }
 
 static inline void root_tag_clear_all(struct radix_tree_root *root)
 {
-        root->gfp_mask &= __GFP_BITS_MASK;
+        root->gfp_mask &= (1 << ROOT_TAG_SHIFT) - 1;
+}
+
+static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag)
+{
+        return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT));
 }
 
-static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
+static inline unsigned root_tags_get(const struct radix_tree_root *root)
 {
-        return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
+        return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT;
 }
 
-static inline unsigned root_tags_get(struct radix_tree_root *root)
+static inline bool is_idr(const struct radix_tree_root *root)
 {
-        return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT;
+        return !!(root->gfp_mask & ROOT_IS_IDR);
 }
 
 /*
  * Returns 1 if any slot in the node has this tag set.
  * Otherwise returns 0.
  */
-static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
+static inline int any_tag_set(const struct radix_tree_node *node,
+                                                        unsigned int tag)
 {
         unsigned idx;
         for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
@@ -184,6 +211,11 @@ static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
         return 0;
 }
 
+static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag)
+{
+        bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE);
+}
+
 /**
  * radix_tree_find_next_bit - find the next set bit in a memory region
  *
@@ -232,11 +264,18 @@ static inline unsigned long shift_maxindex(unsigned int shift)
         return (RADIX_TREE_MAP_SIZE << shift) - 1;
 }
 
-static inline unsigned long node_maxindex(struct radix_tree_node *node)
+static inline unsigned long node_maxindex(const struct radix_tree_node *node)
 {
         return shift_maxindex(node->shift);
 }
 
+static unsigned long next_index(unsigned long index,
+                                const struct radix_tree_node *node,
+                                unsigned long offset)
+{
+        return (index & ~node_maxindex(node)) + (offset << node->shift);
+}
+
 #ifndef __KERNEL__
 static void dump_node(struct radix_tree_node *node, unsigned long index)
 {
@@ -275,11 +314,59 @@ static void radix_tree_dump(struct radix_tree_root *root)
 {
         pr_debug("radix root: %p rnode %p tags %x\n",
                         root, root->rnode,
-                        root->gfp_mask >> __GFP_BITS_SHIFT);
+                        root->gfp_mask >> ROOT_TAG_SHIFT);
         if (!radix_tree_is_internal_node(root->rnode))
                 return;
         dump_node(entry_to_node(root->rnode), 0);
 }
+
+static void dump_ida_node(void *entry, unsigned long index)
+{
+        unsigned long i;
+
+        if (!entry)
+                return;
+
+        if (radix_tree_is_internal_node(entry)) {
+                struct radix_tree_node *node = entry_to_node(entry);
+
+                pr_debug("ida node: %p offset %d indices %lu-%lu parent %p free %lx shift %d count %d\n",
+                        node, node->offset, index * IDA_BITMAP_BITS,
+                        ((index | node_maxindex(node)) + 1) *
+                                IDA_BITMAP_BITS - 1,
+                        node->parent, node->tags[0][0], node->shift,
+                        node->count);
+                for (i = 0; i < RADIX_TREE_MAP_SIZE; i++)
+                        dump_ida_node(node->slots[i],
+                                        index | (i << node->shift));
+        } else if (radix_tree_exceptional_entry(entry)) {
+                pr_debug("ida excp: %p offset %d indices %lu-%lu data %lx\n",
+                                entry, (int)(index & RADIX_TREE_MAP_MASK),
+                                index * IDA_BITMAP_BITS,
+                                index * IDA_BITMAP_BITS + BITS_PER_LONG -
+                                        RADIX_TREE_EXCEPTIONAL_SHIFT,
+                                (unsigned long)entry >>
+                                        RADIX_TREE_EXCEPTIONAL_SHIFT);
+        } else {
+                struct ida_bitmap *bitmap = entry;
+
+                pr_debug("ida btmp: %p offset %d indices %lu-%lu data", bitmap,
+                                (int)(index & RADIX_TREE_MAP_MASK),
+                                index * IDA_BITMAP_BITS,
+                                (index + 1) * IDA_BITMAP_BITS - 1);
+                for (i = 0; i < IDA_BITMAP_LONGS; i++)
+                        pr_cont(" %lx", bitmap->bitmap[i]);
+                pr_cont("\n");
+        }
+}
+
+static void ida_dump(struct ida *ida)
+{
+        struct radix_tree_root *root = &ida->ida_rt;
+        pr_debug("ida: %p node %p free %d\n", ida, root->rnode,
+                                root->gfp_mask >> ROOT_TAG_SHIFT);
+        dump_ida_node(root->rnode, 0);
+}
 #endif
 
 /*
@@ -287,13 +374,12 @@ static void radix_tree_dump(struct radix_tree_root *root)
  * that the caller has pinned this thread of control to the current CPU.
  */
 static struct radix_tree_node *
-radix_tree_node_alloc(struct radix_tree_root *root,
-                        struct radix_tree_node *parent,
+radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
+                        struct radix_tree_root *root,
                         unsigned int shift, unsigned int offset,
                         unsigned int count, unsigned int exceptional)
 {
         struct radix_tree_node *ret = NULL;
-        gfp_t gfp_mask = root_gfp_mask(root);
 
         /*
          * Preload code isn't irq safe and it doesn't make sense to use
@@ -321,8 +407,7 @@ radix_tree_node_alloc(struct radix_tree_root *root,
                 rtp = this_cpu_ptr(&radix_tree_preloads);
                 if (rtp->nr) {
                         ret = rtp->nodes;
-                        rtp->nodes = ret->private_data;
-                        ret->private_data = NULL;
+                        rtp->nodes = ret->parent;
                         rtp->nr--;
                 }
                 /*
@@ -336,11 +421,12 @@ radix_tree_node_alloc(struct radix_tree_root *root,
 out:
         BUG_ON(radix_tree_is_internal_node(ret));
         if (ret) {
-                ret->parent = parent;
                 ret->shift = shift;
                 ret->offset = offset;
                 ret->count = count;
                 ret->exceptional = exceptional;
+                ret->parent = parent;
+                ret->root = root;
         }
         return ret;
 }
@@ -399,7 +485,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
                 preempt_disable();
                 rtp = this_cpu_ptr(&radix_tree_preloads);
                 if (rtp->nr < nr) {
-                        node->private_data = rtp->nodes;
+                        node->parent = rtp->nodes;
                         rtp->nodes = node;
                         rtp->nr++;
                 } else {
@@ -510,7 +596,7 @@ int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order)
         return __radix_tree_preload(gfp_mask, nr_nodes);
 }
 
-static unsigned radix_tree_load_root(struct radix_tree_root *root,
+static unsigned radix_tree_load_root(const struct radix_tree_root *root,
                 struct radix_tree_node **nodep, unsigned long *maxindex)
 {
         struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
@@ -530,10 +616,10 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root,
 /*
  *      Extend a radix tree so it can store key @index.
  */
-static int radix_tree_extend(struct radix_tree_root *root,
+static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
                                 unsigned long index, unsigned int shift)
 {
-        struct radix_tree_node *slot;
+        void *entry;
         unsigned int maxshift;
         int tag;
 
@@ -542,32 +628,44 @@ static int radix_tree_extend(struct radix_tree_root *root,
         while (index > shift_maxindex(maxshift))
                 maxshift += RADIX_TREE_MAP_SHIFT;
 
-        slot = root->rnode;
-        if (!slot)
+        entry = rcu_dereference_raw(root->rnode);
+        if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE)))
                 goto out;
 
         do {
-                struct radix_tree_node *node = radix_tree_node_alloc(root,
-                                                        NULL, shift, 0, 1, 0);
+                struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL,
+                                                        root, shift, 0, 1, 0);
                 if (!node)
                         return -ENOMEM;
 
-                /* Propagate the aggregated tag info into the new root */
-                for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
-                        if (root_tag_get(root, tag))
-                                tag_set(node, tag, 0);
+                if (is_idr(root)) {
+                        all_tag_set(node, IDR_FREE);
+                        if (!root_tag_get(root, IDR_FREE)) {
+                                tag_clear(node, IDR_FREE, 0);
+                                root_tag_set(root, IDR_FREE);
+                        }
+                } else {
+                        /* Propagate the aggregated tag info to the new child */
+                        for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
+                                if (root_tag_get(root, tag))
+                                        tag_set(node, tag, 0);
+                        }
                 }
 
                 BUG_ON(shift > BITS_PER_LONG);
-                if (radix_tree_is_internal_node(slot)) {
-                        entry_to_node(slot)->parent = node;
-                } else if (radix_tree_exceptional_entry(slot)) {
+                if (radix_tree_is_internal_node(entry)) {
+                        entry_to_node(entry)->parent = node;
+                } else if (radix_tree_exceptional_entry(entry)) {
                         /* Moving an exceptional root->rnode to a node */
                         node->exceptional = 1;
                 }
-                node->slots[0] = slot;
-                slot = node_to_entry(node);
-                rcu_assign_pointer(root->rnode, slot);
+                /*
+                 * entry was already in the radix tree, so we do not need
+                 * rcu_assign_pointer here
+                 */
+                node->slots[0] = (void __rcu *)entry;
+                entry = node_to_entry(node);
+                rcu_assign_pointer(root->rnode, entry);
                 shift += RADIX_TREE_MAP_SHIFT;
         } while (shift <= maxshift);
 out:
@@ -578,12 +676,14 @@ out:
  *      radix_tree_shrink    -    shrink radix tree to minimum height
  *      @root           radix tree root
  */
-static inline void radix_tree_shrink(struct radix_tree_root *root,
+static inline bool radix_tree_shrink(struct radix_tree_root *root,
                                      radix_tree_update_node_t update_node,
                                      void *private)
 {
+        bool shrunk = false;
+
         for (;;) {
-                struct radix_tree_node *node = root->rnode;
+                struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
                 struct radix_tree_node *child;
 
                 if (!radix_tree_is_internal_node(node))
@@ -597,7 +697,7 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
                  */
                 if (node->count != 1)
                         break;
-                child = node->slots[0];
+                child = rcu_dereference_raw(node->slots[0]);
                 if (!child)
                         break;
                 if (!radix_tree_is_internal_node(child) && node->shift)
@@ -613,7 +713,9 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
                  * (node->slots[0]), it will be safe to dereference the new
                  * one (root->rnode) as far as dependent read barriers go.
                  */
-                root->rnode = child;
+                root->rnode = (void __rcu *)child;
+                if (is_idr(root) && !tag_get(node, IDR_FREE, 0))
+                        root_tag_clear(root, IDR_FREE);
 
                 /*
                  * We have a dilemma here. The node's slot[0] must not be
@@ -635,27 +737,34 @@ static inline void radix_tree_shrink(struct radix_tree_root *root,
                  */
                 node->count = 0;
                 if (!radix_tree_is_internal_node(child)) {
-                        node->slots[0] = RADIX_TREE_RETRY;
+                        node->slots[0] = (void __rcu *)RADIX_TREE_RETRY;
                         if (update_node)
                                 update_node(node, private);
                 }
 
                 WARN_ON_ONCE(!list_empty(&node->private_list));
                 radix_tree_node_free(node);
+                shrunk = true;
         }
+
+        return shrunk;
 }
 
-static void delete_node(struct radix_tree_root *root,
+static bool delete_node(struct radix_tree_root *root,
                         struct radix_tree_node *node,
                         radix_tree_update_node_t update_node, void *private)
 {
+        bool deleted = false;
+
         do {
                 struct radix_tree_node *parent;
 
                 if (node->count) {
-                        if (node == entry_to_node(root->rnode))
-                                radix_tree_shrink(root, update_node, private);
-                        return;
+                        if (node_to_entry(node) ==
+                                        rcu_dereference_raw(root->rnode))
+                                deleted |= radix_tree_shrink(root, update_node,
+                                                                private);
+                        return deleted;
                 }
 
                 parent = node->parent;
@@ -663,15 +772,23 @@ static void delete_node(struct radix_tree_root *root,
                         parent->slots[node->offset] = NULL;
                         parent->count--;
                 } else {
-                        root_tag_clear_all(root);
+                        /*
+                         * Shouldn't the tags already have all been cleared
+                         * by the caller?
+                         */
+                        if (!is_idr(root))
+                                root_tag_clear_all(root);
                         root->rnode = NULL;
                 }
 
                 WARN_ON_ONCE(!list_empty(&node->private_list));
                 radix_tree_node_free(node);
+                deleted = true;
 
                 node = parent;
         } while (node);
+
+        return deleted;
 }
 
 /**
@@ -693,13 +810,14 @@ static void delete_node(struct radix_tree_root *root,
  */
 int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
                         unsigned order, struct radix_tree_node **nodep,
-                        void ***slotp)
+                        void __rcu ***slotp)
 {
         struct radix_tree_node *node = NULL, *child;
-        void **slot = (void **)&root->rnode;
+        void __rcu **slot = (void __rcu **)&root->rnode;
         unsigned long maxindex;
         unsigned int shift, offset = 0;
         unsigned long max = index | ((1UL << order) - 1);
+        gfp_t gfp = root_gfp_mask(root);
 
         shift = radix_tree_load_root(root, &child, &maxindex);
 
@@ -707,18 +825,18 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
         if (order > 0 && max == ((1UL << order) - 1))
                 max++;
         if (max > maxindex) {
-                int error = radix_tree_extend(root, max, shift);
+                int error = radix_tree_extend(root, gfp, max, shift);
                 if (error < 0)
                         return error;
                 shift = error;
-                child = root->rnode;
+                child = rcu_dereference_raw(root->rnode);
         }
 
         while (shift > order) {
                 shift -= RADIX_TREE_MAP_SHIFT;
                 if (child == NULL) {
                         /* Have to add a child node.  */
-                        child = radix_tree_node_alloc(root, node, shift,
+                        child = radix_tree_node_alloc(gfp, node, root, shift,
                                                         offset, 0, 0);
                         if (!child)
                                 return -ENOMEM;
@@ -741,7 +859,6 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
         return 0;
 }
 
-#ifdef CONFIG_RADIX_TREE_MULTIORDER
 /*
  * Free any nodes below this node.  The tree is presumed to not need
  * shrinking, and any user data in the tree is presumed to not need a
@@ -757,7 +874,7 @@ static void radix_tree_free_nodes(struct radix_tree_node *node)
         struct radix_tree_node *child = entry_to_node(node);
 
         for (;;) {
-                void *entry = child->slots[offset];
+                void *entry = rcu_dereference_raw(child->slots[offset]);
                 if (radix_tree_is_internal_node(entry) &&
                                         !is_sibling_entry(child, entry)) {
                         child = entry_to_node(entry);
@@ -777,8 +894,9 @@ static void radix_tree_free_nodes(struct radix_tree_node *node)
         }
 }
 
-static inline int insert_entries(struct radix_tree_node *node, void **slot,
-                                void *item, unsigned order, bool replace)
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+static inline int insert_entries(struct radix_tree_node *node,
+                void __rcu **slot, void *item, unsigned order, bool replace)
 {
         struct radix_tree_node *child;
         unsigned i, n, tag, offset, tags = 0;
@@ -813,7 +931,7 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot,
         }
 
         for (i = 0; i < n; i++) {
-                struct radix_tree_node *old = slot[i];
+                struct radix_tree_node *old = rcu_dereference_raw(slot[i]);
                 if (i) {
                         rcu_assign_pointer(slot[i], child);
                         for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
@@ -840,8 +958,8 @@ static inline int insert_entries(struct radix_tree_node *node, void **slot,
         return n;
 }
 #else
-static inline int insert_entries(struct radix_tree_node *node, void **slot,
-                                void *item, unsigned order, bool replace)
+static inline int insert_entries(struct radix_tree_node *node,
+                void __rcu **slot, void *item, unsigned order, bool replace)
 {
         if (*slot)
                 return -EEXIST;
@@ -868,7 +986,7 @@ int __radix_tree_insert(struct radix_tree_root *root, unsigned long index,
                         unsigned order, void *item)
 {
         struct radix_tree_node *node;
-        void **slot;
+        void __rcu **slot;
         int error;
 
         BUG_ON(radix_tree_is_internal_node(item));
@@ -908,16 +1026,17 @@ EXPORT_SYMBOL(__radix_tree_insert);
  *      allocated and @root->rnode is used as a direct slot instead of
  *      pointing to a node, in which case *@nodep will be NULL.
  */
-void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
-                          struct radix_tree_node **nodep, void ***slotp)
+void *__radix_tree_lookup(const struct radix_tree_root *root,
+                          unsigned long index, struct radix_tree_node **nodep,
+                          void __rcu ***slotp)
 {
         struct radix_tree_node *node, *parent;
         unsigned long maxindex;
-        void **slot;
+        void __rcu **slot;
 
  restart:
         parent = NULL;
-        slot = (void **)&root->rnode;
+        slot = (void __rcu **)&root->rnode;
         radix_tree_load_root(root, &node, &maxindex);
         if (index > maxindex)
                 return NULL;
@@ -952,9 +1071,10 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
  *      exclusive from other writers. Any dereference of the slot must be done
  *      using radix_tree_deref_slot.
  */
-void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
+void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root,
+                                unsigned long index)
 {
-        void **slot;
+        void __rcu **slot;
 
         if (!__radix_tree_lookup(root, index, NULL, &slot))
                 return NULL;
@@ -974,75 +1094,76 @@ EXPORT_SYMBOL(radix_tree_lookup_slot);
  *      them safely). No RCU barriers are required to access or modify the
  *      returned item, however.
  */
-void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
+void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index)
 {
         return __radix_tree_lookup(root, index, NULL, NULL);
 }
 EXPORT_SYMBOL(radix_tree_lookup);
 
-static inline int slot_count(struct radix_tree_node *node,
-                                                void **slot)
+static inline void replace_sibling_entries(struct radix_tree_node *node,
+                                void __rcu **slot, int count, int exceptional)
 {
-        int n = 1;
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
         void *ptr = node_to_entry(slot);
-        unsigned offset = get_slot_offset(node, slot);
-        int i;
+        unsigned offset = get_slot_offset(node, slot) + 1;
 
-        for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
-                if (node->slots[offset + i] != ptr)
+        while (offset < RADIX_TREE_MAP_SIZE) {
+                if (rcu_dereference_raw(node->slots[offset]) != ptr)
                         break;
-                n++;
+                if (count < 0) {
+                        node->slots[offset] = NULL;
+                        node->count--;
+                }
+                node->exceptional += exceptional;
+                offset++;
         }
 #endif
-        return n;
 }
 
-static void replace_slot(struct radix_tree_root *root,
-                         struct radix_tree_node *node,
-                         void **slot, void *item,
-                         bool warn_typeswitch)
+static void replace_slot(void __rcu **slot, void *item,
+                struct radix_tree_node *node, int count, int exceptional)
 {
-        void *old = rcu_dereference_raw(*slot);
-        int count, exceptional;
-
-        WARN_ON_ONCE(radix_tree_is_internal_node(item));
-
-        count = !!item - !!old;
-        exceptional = !!radix_tree_exceptional_entry(item) -
-                      !!radix_tree_exceptional_entry(old);
-
-        WARN_ON_ONCE(warn_typeswitch && (count || exceptional));
+        if (WARN_ON_ONCE(radix_tree_is_internal_node(item)))
+                return;
 
-        if (node) {
+        if (node && (count || exceptional)) {
                 node->count += count;
-                if (exceptional) {
-                        exceptional *= slot_count(node, slot);
-                        node->exceptional += exceptional;
-                }
+                node->exceptional += exceptional;
+                replace_sibling_entries(node, slot, count, exceptional);
         }
 
         rcu_assign_pointer(*slot, item);
 }
 
-static inline void delete_sibling_entries(struct radix_tree_node *node,
-                                                void **slot)
+static bool node_tag_get(const struct radix_tree_root *root,
+                                const struct radix_tree_node *node,
+                                unsigned int tag, unsigned int offset)
 {
-#ifdef CONFIG_RADIX_TREE_MULTIORDER
-        bool exceptional = radix_tree_exceptional_entry(*slot);
-        void *ptr = node_to_entry(slot);
-        unsigned offset = get_slot_offset(node, slot);
-        int i;
+        if (node)
+                return tag_get(node, tag, offset);
+        return root_tag_get(root, tag);
+}
 
-        for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
-                if (node->slots[offset + i] != ptr)
-                        break;
-                node->slots[offset + i] = NULL;
-                node->count--;
-                if (exceptional)
-                        node->exceptional--;
+/*
+ * IDR users want to be able to store NULL in the tree, so if the slot isn't
+ * free, don't adjust the count, even if it's transitioning between NULL and
+ * non-NULL.  For the IDA, we mark slots as being IDR_FREE while they still
+ * have empty bits, but it only stores NULL in slots when they're being
+ * deleted.
+ */
+static int calculate_count(struct radix_tree_root *root,
+                                struct radix_tree_node *node, void __rcu **slot,
+                                void *item, void *old)
+{
+        if (is_idr(root)) {
+                unsigned offset = get_slot_offset(node, slot);
+                bool free = node_tag_get(root, node, IDR_FREE, offset);
+                if (!free)
+                        return 0;
+                if (!old)
+                        return 1;
         }
-#endif
+        return !!item - !!old;
 }
 
 /**
@@ -1059,18 +1180,22 @@ static inline void delete_sibling_entries(struct radix_tree_node *node,
  */
 void __radix_tree_replace(struct radix_tree_root *root,
                           struct radix_tree_node *node,
-                          void **slot, void *item,
+                          void __rcu **slot, void *item,
                           radix_tree_update_node_t update_node, void *private)
 {
-        if (!item)
-                delete_sibling_entries(node, slot);
+        void *old = rcu_dereference_raw(*slot);
+        int exceptional = !!radix_tree_exceptional_entry(item) -
+                                !!radix_tree_exceptional_entry(old);
+        int count = calculate_count(root, node, slot, item, old);
+
         /*
          * This function supports replacing exceptional entries and
          * deleting entries, but that needs accounting against the
          * node unless the slot is root->rnode.
          */
-        replace_slot(root, node, slot, item,
-                     !node && slot != (void **)&root->rnode);
+        WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) &&
+                        (count || exceptional));
+        replace_slot(slot, item, node, count, exceptional);
 
         if (!node)
                 return;
@@ -1098,10 +1223,11 @@ void __radix_tree_replace(struct radix_tree_root *root,
  * radix_tree_iter_replace().
  */
 void radix_tree_replace_slot(struct radix_tree_root *root,
-                             void **slot, void *item)
+                             void __rcu **slot, void *item)
 {
-        replace_slot(root, NULL, slot, item, true);
+        __radix_tree_replace(root, NULL, slot, item, NULL, NULL);
 }
+EXPORT_SYMBOL(radix_tree_replace_slot);
 
 /**
  * radix_tree_iter_replace - replace item in a slot
@@ -1113,7 +1239,8 @@ void radix_tree_replace_slot(struct radix_tree_root *root,
  * Caller must hold tree write locked across split and replacement.
  */
 void radix_tree_iter_replace(struct radix_tree_root *root,
-                const struct radix_tree_iter *iter, void **slot, void *item)
+                                const struct radix_tree_iter *iter,
+                                void __rcu **slot, void *item)
 {
         __radix_tree_replace(root, iter->node, slot, item, NULL, NULL);
 }
@@ -1137,7 +1264,7 @@ int radix_tree_join(struct radix_tree_root *root, unsigned long index,
                         unsigned order, void *item)
 {
         struct radix_tree_node *node;
-        void **slot;
+        void __rcu **slot;
         int error;
 
         BUG_ON(radix_tree_is_internal_node(item));
@@ -1172,9 +1299,10 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
                                 unsigned order)
 {
         struct radix_tree_node *parent, *node, *child;
-        void **slot;
+        void __rcu **slot;
         unsigned int offset, end;
         unsigned n, tag, tags = 0;
+        gfp_t gfp = root_gfp_mask(root);
 
         if (!__radix_tree_lookup(root, index, &parent, &slot))
                 return -ENOENT;
@@ -1188,7 +1316,8 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
                         tags |= 1 << tag;
 
         for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) {
-                if (!is_sibling_entry(parent, parent->slots[end]))
+                if (!is_sibling_entry(parent,
+                                rcu_dereference_raw(parent->slots[end])))
                         break;
                 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
                         if (tags & (1 << tag))
@@ -1212,14 +1341,15 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
 
         for (;;) {
                 if (node->shift > order) {
-                        child = radix_tree_node_alloc(root, node,
+                        child = radix_tree_node_alloc(gfp, node, root,
                                         node->shift - RADIX_TREE_MAP_SHIFT,
                                         offset, 0, 0);
                         if (!child)
                                 goto nomem;
                         if (node != parent) {
                                 node->count++;
-                                node->slots[offset] = node_to_entry(child);
+                                rcu_assign_pointer(node->slots[offset],
+                                                        node_to_entry(child));
                                 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
                                         if (tags & (1 << tag))
                                                 tag_set(node, tag, offset);
@@ -1261,6 +1391,22 @@ int radix_tree_split(struct radix_tree_root *root, unsigned long index,
 }
 #endif
 
+static void node_tag_set(struct radix_tree_root *root,
+                                struct radix_tree_node *node,
+                                unsigned int tag, unsigned int offset)
+{
+        while (node) {
+                if (tag_get(node, tag, offset))
+                        return;
+                tag_set(node, tag, offset);
+                offset = node->offset;
+                node = node->parent;
+        }
+
+        if (!root_tag_get(root, tag))
+                root_tag_set(root, tag);
+}
+
 /**
  *      radix_tree_tag_set - set a tag on a radix tree node
  *      @root:          radix tree root
@@ -1302,6 +1448,18 @@ void *radix_tree_tag_set(struct radix_tree_root *root,
 }
 EXPORT_SYMBOL(radix_tree_tag_set);
 
+/**
+ * radix_tree_iter_tag_set - set a tag on the current iterator entry
+ * @root:       radix tree root
+ * @iter:       iterator state
+ * @tag:        tag to set
+ */
+void radix_tree_iter_tag_set(struct radix_tree_root *root,
+                        const struct radix_tree_iter *iter, unsigned int tag)
+{
+        node_tag_set(root, iter->node, tag, iter_offset(iter));
+}
+
 static void node_tag_clear(struct radix_tree_root *root,
                                 struct radix_tree_node *node,
                                 unsigned int tag, unsigned int offset)
@@ -1322,34 +1480,6 @@ static void node_tag_clear(struct radix_tree_root *root,
                 root_tag_clear(root, tag);
 }
 
-static void node_tag_set(struct radix_tree_root *root,
-                                struct radix_tree_node *node,
-                                unsigned int tag, unsigned int offset)
-{
-        while (node) {
-                if (tag_get(node, tag, offset))
-                        return;
-                tag_set(node, tag, offset);
-                offset = node->offset;
-                node = node->parent;
-        }
-
-        if (!root_tag_get(root, tag))
-                root_tag_set(root, tag);
-}
-
-/**
- * radix_tree_iter_tag_set - set a tag on the current iterator entry
- * @root:       radix tree root
- * @iter:       iterator state
- * @tag:        tag to set
- */
-void radix_tree_iter_tag_set(struct radix_tree_root *root,
-                        const struct radix_tree_iter *iter, unsigned int tag)
-{
-        node_tag_set(root, iter->node, tag, iter_offset(iter));
-}
-
 /**
  *      radix_tree_tag_clear - clear a tag on a radix tree node
  *      @root:          radix tree root
@@ -1390,6 +1520,18 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
 EXPORT_SYMBOL(radix_tree_tag_clear);
 
 /**
+  * radix_tree_iter_tag_clear - clear a tag on the current iterator entry
+  * @root: radix tree root
+  * @iter: iterator state
+  * @tag: tag to clear
+  */
+void radix_tree_iter_tag_clear(struct radix_tree_root *root,
+                        const struct radix_tree_iter *iter, unsigned int tag)
+{
+        node_tag_clear(root, iter->node, tag, iter_offset(iter));
+}
+
+/**
  * radix_tree_tag_get - get a tag on a radix tree node
  * @root:               radix tree root
  * @index:              index key
@@ -1404,7 +1546,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear);
  * the RCU lock is held, unless tag modification and node deletion are excluded
  * from concurrency.
  */
-int radix_tree_tag_get(struct radix_tree_root *root,
+int radix_tree_tag_get(const struct radix_tree_root *root,
                         unsigned long index, unsigned int tag)
 {
         struct radix_tree_node *node, *parent;
@@ -1416,8 +1558,6 @@ int radix_tree_tag_get(struct radix_tree_root *root,
         radix_tree_load_root(root, &node, &maxindex);
         if (index > maxindex)
                 return 0;
-        if (node == NULL)
-                return 0;
 
         while (radix_tree_is_internal_node(node)) {
                 unsigned offset;
@@ -1425,8 +1565,6 @@ int radix_tree_tag_get(struct radix_tree_root *root,
                 parent = entry_to_node(node);
                 offset = radix_tree_descend(parent, &node, index);
 
-                if (!node)
-                        return 0;
                 if (!tag_get(parent, tag, offset))
                         return 0;
                 if (node == RADIX_TREE_RETRY)
@@ -1453,6 +1591,11 @@ static void set_iter_tags(struct radix_tree_iter *iter,
         unsigned tag_long = offset / BITS_PER_LONG;
         unsigned tag_bit  = offset % BITS_PER_LONG;
 
+        if (!node) {
+                iter->tags = 1;
+                return;
+        }
+
         iter->tags = node->tags[tag][tag_long] >> tag_bit;
 
         /* This never happens if RADIX_TREE_TAG_LONGS == 1 */
@@ -1467,8 +1610,8 @@ static void set_iter_tags(struct radix_tree_iter *iter,
 }
 
 #ifdef CONFIG_RADIX_TREE_MULTIORDER
-static void **skip_siblings(struct radix_tree_node **nodep,
-                        void **slot, struct radix_tree_iter *iter)
+static void __rcu **skip_siblings(struct radix_tree_node **nodep,
+                        void __rcu **slot, struct radix_tree_iter *iter)
 {
         void *sib = node_to_entry(slot - 1);
 
@@ -1485,8 +1628,8 @@ static void **skip_siblings(struct radix_tree_node **nodep,
         return NULL;
 }
 
-void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter,
-                                        unsigned flags)
+void __rcu **__radix_tree_next_slot(void __rcu **slot,
+                                struct radix_tree_iter *iter, unsigned flags)
 {
         unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
         struct radix_tree_node *node = rcu_dereference_raw(*slot);
@@ -1539,20 +1682,20 @@ void ** __radix_tree_next_slot(void **slot, struct radix_tree_iter *iter,
 }
 EXPORT_SYMBOL(__radix_tree_next_slot);
 #else
-static void **skip_siblings(struct radix_tree_node **nodep,
-                        void **slot, struct radix_tree_iter *iter)
+static void __rcu **skip_siblings(struct radix_tree_node **nodep,
+                        void __rcu **slot, struct radix_tree_iter *iter)
 {
         return slot;
 }
 #endif
 
-void **radix_tree_iter_resume(void **slot, struct radix_tree_iter *iter)
+void __rcu **radix_tree_iter_resume(void __rcu **slot,
+                                        struct radix_tree_iter *iter)
 {
         struct radix_tree_node *node;
 
         slot++;
         iter->index = __radix_tree_iter_add(iter, 1);
-        node = rcu_dereference_raw(*slot);
         skip_siblings(&node, slot, iter);
         iter->next_index = iter->index;
         iter->tags = 0;
@@ -1568,7 +1711,7 @@ EXPORT_SYMBOL(radix_tree_iter_resume);
  * @flags:      RADIX_TREE_ITER_* flags and tag index
  * Returns:     pointer to chunk first slot, or NULL if iteration is over
  */
-void **radix_tree_next_chunk(struct radix_tree_root *root,
+void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root,
                              struct radix_tree_iter *iter, unsigned flags)
 {
         unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
@@ -1605,7 +1748,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
                 iter->tags = 1;
                 iter->node = NULL;
                 __set_iter_shift(iter, 0);
-                return (void **)&root->rnode;
+                return (void __rcu **)&root->rnode;
         }
 
         do {
@@ -1623,7 +1766,8 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
                                                 offset + 1);
                         else
                                 while (++offset < RADIX_TREE_MAP_SIZE) {
-                                        void *slot = node->slots[offset];
+                                        void *slot = rcu_dereference_raw(
+                                                        node->slots[offset]);
                                         if (is_sibling_entry(node, slot))
                                                 continue;
                                         if (slot)
@@ -1679,11 +1823,11 @@ EXPORT_SYMBOL(radix_tree_next_chunk);
  *      stored in 'results'.
  */
 unsigned int
-radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
+radix_tree_gang_lookup(const struct radix_tree_root *root, void **results,
                         unsigned long first_index, unsigned int max_items)
 {
         struct radix_tree_iter iter;
-        void **slot;
+        void __rcu **slot;
         unsigned int ret = 0;
 
         if (unlikely(!max_items))
@@ -1724,12 +1868,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup);
  *      protection, radix_tree_deref_slot may fail requiring a retry.
  */
 unsigned int
-radix_tree_gang_lookup_slot(struct radix_tree_root *root,
-                        void ***results, unsigned long *indices,
+radix_tree_gang_lookup_slot(const struct radix_tree_root *root,
+                        void __rcu ***results, unsigned long *indices,
                         unsigned long first_index, unsigned int max_items)
 {
         struct radix_tree_iter iter;
-        void **slot;
+        void __rcu **slot;
         unsigned int ret = 0;
 
         if (unlikely(!max_items))
@@ -1761,12 +1905,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
  *      returns the number of items which were placed at *@results.
  */
 unsigned int
-radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
+radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results,
                 unsigned long first_index, unsigned int max_items,
                 unsigned int tag)
 {
         struct radix_tree_iter iter;
-        void **slot;
+        void __rcu **slot;
         unsigned int ret = 0;
 
         if (unlikely(!max_items))
@@ -1802,12 +1946,12 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
  *      returns the number of slots which were placed at *@results.
  */
 unsigned int
-radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
-                unsigned long first_index, unsigned int max_items,
-                unsigned int tag)
+radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root,
+                void __rcu ***results, unsigned long first_index,
+                unsigned int max_items, unsigned int tag)
 {
         struct radix_tree_iter iter;
-        void **slot;
+        void __rcu **slot;
         unsigned int ret = 0;
 
         if (unlikely(!max_items))
@@ -1842,59 +1986,83 @@ void __radix_tree_delete_node(struct radix_tree_root *root,
         delete_node(root, node, update_node, private);
 }
 
+static bool __radix_tree_delete(struct radix_tree_root *root,
+                                struct radix_tree_node *node, void __rcu **slot)
+{
+        void *old = rcu_dereference_raw(*slot);
+        int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0;
+        unsigned offset = get_slot_offset(node, slot);
+        int tag;
+
+        if (is_idr(root))
+                node_tag_set(root, node, IDR_FREE, offset);
+        else
+                for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+                        node_tag_clear(root, node, tag, offset);
+
+        replace_slot(slot, NULL, node, -1, exceptional);
+        return node && delete_node(root, node, NULL, NULL);
+}
+
 /**
- *      radix_tree_delete_item    -    delete an item from a radix tree
- *      @root:          radix tree root
- *      @index:         index key
- *      @item:          expected item
+ * radix_tree_iter_delete - delete the entry at this iterator position
+ * @root: radix tree root
+ * @iter: iterator state
+ * @slot: pointer to slot
  *
- *      Remove @item at @index from the radix tree rooted at @root.
+ * Delete the entry at the position currently pointed to by the iterator.
+ * This may result in the current node being freed; if it is, the iterator
+ * is advanced so that it will not reference the freed memory.  This
+ * function may be called without any locking if there are no other threads
+ * which can access this tree.
+ */
+void radix_tree_iter_delete(struct radix_tree_root *root,
+                                struct radix_tree_iter *iter, void __rcu **slot)
+{
+        if (__radix_tree_delete(root, iter->node, slot))
+                iter->index = iter->next_index;
+}
+
+/**
+ * radix_tree_delete_item - delete an item from a radix tree
+ * @root: radix tree root
+ * @index: index key
+ * @item: expected item
  *
- *      Returns the address of the deleted item, or NULL if it was not present
- *      or the entry at the given @index was not @item.
+ * Remove @item at @index from the radix tree rooted at @root.
+ *
+ * Return: the deleted entry, or %NULL if it was not present
+ * or the entry at the given @index was not @item.
  */
 void *radix_tree_delete_item(struct radix_tree_root *root,
                              unsigned long index, void *item)
 {
-        struct radix_tree_node *node;
-        unsigned int offset;
-        void **slot;
+        struct radix_tree_node *node = NULL;
+        void __rcu **slot;
         void *entry;
-        int tag;
 
         entry = __radix_tree_lookup(root, index, &node, &slot);
-        if (!entry)
+        if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE,
+                                                get_slot_offset(node, slot))))
                 return NULL;
 
         if (item && entry != item)
                 return NULL;
 
-        if (!node) {
-                root_tag_clear_all(root);
-                root->rnode = NULL;
-                return entry;
-        }
-
-        offset = get_slot_offset(node, slot);
-
-        /* Clear all tags associated with the item to be deleted.  */
-        for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
-                node_tag_clear(root, node, tag, offset);
-
-        __radix_tree_replace(root, node, slot, NULL, NULL, NULL);
+        __radix_tree_delete(root, node, slot);
 
         return entry;
 }
 EXPORT_SYMBOL(radix_tree_delete_item);
 
 /**
- *      radix_tree_delete    -    delete an item from a radix tree
- *      @root:          radix tree root
- *      @index:         index key
+ * radix_tree_delete - delete an entry from a radix tree
+ * @root: radix tree root
+ * @index: index key
  *
- *      Remove the item at @index from the radix tree rooted at @root.
+ * Remove the entry at @index from the radix tree rooted at @root.
  *
- *      Returns the address of the deleted item, or NULL if it was not present.
+ * Return: The deleted entry, or %NULL if it was not present.
  */
 void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
 {
@@ -1904,15 +2072,14 @@ EXPORT_SYMBOL(radix_tree_delete);
 
 void radix_tree_clear_tags(struct radix_tree_root *root,
                            struct radix_tree_node *node,
-                           void **slot)
+                           void __rcu **slot)
 {
         if (node) {
                 unsigned int tag, offset = get_slot_offset(node, slot);
                 for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
                         node_tag_clear(root, node, tag, offset);
         } else {
-                /* Clear root node tags */
-                root->gfp_mask &= __GFP_BITS_MASK;
+                root_tag_clear_all(root);
         }
 }
 
@@ -1921,12 +2088,147 @@ void radix_tree_clear_tags(struct radix_tree_root *root,
  *      @root:          radix tree root
  *      @tag:           tag to test
  */
-int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
+int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag)
 {
         return root_tag_get(root, tag);
 }
 EXPORT_SYMBOL(radix_tree_tagged);
 
+/**
+ * idr_preload - preload for idr_alloc()
+ * @gfp_mask: allocation mask to use for preloading
+ *
+ * Preallocate memory to use for the next call to idr_alloc().  This function
+ * returns with preemption disabled.  It will be enabled by idr_preload_end().
+ */
+void idr_preload(gfp_t gfp_mask)
+{
+        __radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE);
+}
+EXPORT_SYMBOL(idr_preload);
+
+/**
+ * ida_pre_get - reserve resources for ida allocation
+ * @ida: ida handle
+ * @gfp: memory allocation flags
+ *
+ * This function should be called before calling ida_get_new_above().  If it
+ * is unable to allocate memory, it will return %0.  On success, it returns %1.
+ */
+int ida_pre_get(struct ida *ida, gfp_t gfp)
+{
+        __radix_tree_preload(gfp, IDA_PRELOAD_SIZE);
+        /*
+         * The IDA API has no preload_end() equivalent.  Instead,
+         * ida_get_new() can return -EAGAIN, prompting the caller
+         * to return to the ida_pre_get() step.
+         */
+        preempt_enable();
+
+        if (!this_cpu_read(ida_bitmap)) {
+                struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp);
+                if (!bitmap)
+                        return 0;
+                if (this_cpu_cmpxchg(ida_bitmap, NULL, bitmap))
+                        kfree(bitmap);
+        }
+
+        return 1;
+}
+EXPORT_SYMBOL(ida_pre_get);
+
+void __rcu **idr_get_free(struct radix_tree_root *root,
+                        struct radix_tree_iter *iter, gfp_t gfp, int end)
+{
+        struct radix_tree_node *node = NULL, *child;
+        void __rcu **slot = (void __rcu **)&root->rnode;
+        unsigned long maxindex, start = iter->next_index;
+        unsigned long max = end > 0 ? end - 1 : INT_MAX;
+        unsigned int shift, offset = 0;
+
+ grow:
+        shift = radix_tree_load_root(root, &child, &maxindex);
+        if (!radix_tree_tagged(root, IDR_FREE))
+                start = max(start, maxindex + 1);
+        if (start > max)
+                return ERR_PTR(-ENOSPC);
+
+        if (start > maxindex) {
+                int error = radix_tree_extend(root, gfp, start, shift);
+                if (error < 0)
+                        return ERR_PTR(error);
+                shift = error;
+                child = rcu_dereference_raw(root->rnode);
+        }
+
+        while (shift) {
+                shift -= RADIX_TREE_MAP_SHIFT;
+                if (child == NULL) {
+                        /* Have to add a child node.  */
+                        child = radix_tree_node_alloc(gfp, node, root, shift,
+                                                        offset, 0, 0);
+                        if (!child)
+                                return ERR_PTR(-ENOMEM);
+                        all_tag_set(child, IDR_FREE);
+                        rcu_assign_pointer(*slot, node_to_entry(child));
+                        if (node)
+                                node->count++;
+                } else if (!radix_tree_is_internal_node(child))
+                        break;
+
+                node = entry_to_node(child);
+                offset = radix_tree_descend(node, &child, start);
+                if (!tag_get(node, IDR_FREE, offset)) {
+                        offset = radix_tree_find_next_bit(node, IDR_FREE,
+                                                        offset + 1);
+                        start = next_index(start, node, offset);
+                        if (start > max)
+                                return ERR_PTR(-ENOSPC);
+                        while (offset == RADIX_TREE_MAP_SIZE) {
+                                offset = node->offset + 1;
+                                node = node->parent;
+                                if (!node)
+                                        goto grow;
+                                shift = node->shift;
+                        }
+                        child = rcu_dereference_raw(node->slots[offset]);
+                }
+                slot = &node->slots[offset];
+        }
+
+        iter->index = start;
+        if (node)
+                iter->next_index = 1 + min(max, (start | node_maxindex(node)));
+        else
+                iter->next_index = 1;
+        iter->node = node;
+        __set_iter_shift(iter, shift);
+        set_iter_tags(iter, node, offset, IDR_FREE);
+
+        return slot;
+}
+
+/**
+ * idr_destroy - release all internal memory from an IDR
+ * @idr: idr handle
+ *
+ * After this function is called, the IDR is empty, and may be reused or
+ * the data structure containing it may be freed.
+ *
+ * A typical clean-up sequence for objects stored in an idr tree will use
+ * idr_for_each() to free all objects, if necessary, then idr_destroy() to
+ * free the memory used to keep track of those objects.
+ */
+void idr_destroy(struct idr *idr)
+{
+        struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.rnode);
+        if (radix_tree_is_internal_node(node))
+                radix_tree_free_nodes(node);
+        idr->idr_rt.rnode = NULL;
+        root_tag_set(&idr->idr_rt, IDR_FREE);
+}
+EXPORT_SYMBOL(idr_destroy);
+
 static void
 radix_tree_node_ctor(void *arg)
 {
@@ -1970,10 +2272,12 @@ static int radix_tree_cpu_dead(unsigned int cpu)
         rtp = &per_cpu(radix_tree_preloads, cpu);
         while (rtp->nr) {
                 node = rtp->nodes;
-                rtp->nodes = node->private_data;
+                rtp->nodes = node->parent;
                 kmem_cache_free(radix_tree_node_cachep, node);
                 rtp->nr--;
         }
+        kfree(per_cpu(ida_bitmap, cpu));
+        per_cpu(ida_bitmap, cpu) = NULL;
         return 0;
 }