1 files changed, 60 insertions, 0 deletions

diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 15eab63286ed..7f740f675b96 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -275,6 +275,8 @@ struct xarray {
 void xa_init_flags(struct xarray *, gfp_t flags);
 void *xa_load(struct xarray *, unsigned long index);
 void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
+void *xa_cmpxchg(struct xarray *, unsigned long index,
+                        void *old, void *entry, gfp_t);
 bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t);
 void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t);
 void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t);
@@ -334,6 +336,34 @@ static inline void *xa_erase(struct xarray *xa, unsigned long index)
         return xa_store(xa, index, NULL, 0);
 }
 
+/**
+ * xa_insert() - Store this entry in the XArray unless another entry is
+ *                      already present.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * If you would rather see the existing entry in the array, use xa_cmpxchg().
+ * This function is for users who don't care what the entry is, only that
+ * one is present.
+ *
+ * Context: Process context.  Takes and releases the xa_lock.
+ *          May sleep if the @gfp flags permit.
+ * Return: 0 if the store succeeded.  -EEXIST if another entry was present.
+ * -ENOMEM if memory could not be allocated.
+ */
+static inline int xa_insert(struct xarray *xa, unsigned long index,
+                void *entry, gfp_t gfp)
+{
+        void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp);
+        if (!curr)
+                return 0;
+        if (xa_is_err(curr))
+                return xa_err(curr);
+        return -EEXIST;
+}
+
 #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)
@@ -355,10 +385,40 @@ static inline void *xa_erase(struct xarray *xa, unsigned long index)
  */
 void *__xa_erase(struct xarray *, unsigned long index);
 void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
+void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old,
+                void *entry, gfp_t);
 void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t);
 void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t);
 
 /**
+ * __xa_insert() - Store this entry in the XArray unless another entry is
+ *                      already present.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * If you would rather see the existing entry in the array, use __xa_cmpxchg().
+ * This function is for users who don't care what the entry is, only that
+ * one is present.
+ *
+ * Context: Any context.  Expects xa_lock to be held on entry.  May
+ *          release and reacquire xa_lock if the @gfp flags permit.
+ * Return: 0 if the store succeeded.  -EEXIST if another entry was present.
+ * -ENOMEM if memory could not be allocated.
+ */
+static inline int __xa_insert(struct xarray *xa, unsigned long index,
+                void *entry, gfp_t gfp)
+{
+        void *curr = __xa_cmpxchg(xa, index, NULL, entry, gfp);
+        if (!curr)
+                return 0;
+        if (xa_is_err(curr))
+                return xa_err(curr);
+        return -EEXIST;
+}
+
+/**
  * xa_erase_bh() - Erase this entry from the XArray.
  * @xa: XArray.
  * @index: Index of entry.