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-rw-r--r--include/linux/idr.h2
-rw-r--r--lib/idr.c31
2 files changed, 33 insertions, 0 deletions
diff --git a/include/linux/idr.h b/include/linux/idr.h
index 7867d6117535..561a4cbabca6 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -131,6 +131,8 @@ static inline int idr_alloc_ext(struct idr *idr, void *ptr,
return idr_alloc_cmn(idr, ptr, index, start, end, gfp, true);
}
+int __must_check idr_alloc_u32(struct idr *, void *ptr, u32 *nextid,
+ unsigned long max, gfp_t);
int idr_alloc_cyclic(struct idr *, void *entry, int start, int end, gfp_t);
int idr_for_each(const struct idr *,
int (*fn)(int id, void *p, void *data), void *data);
diff --git a/lib/idr.c b/lib/idr.c
index 577bfd4fe5c2..6d4ec2c2982b 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -7,6 +7,37 @@
DEFINE_PER_CPU(struct ida_bitmap *, ida_bitmap);
static DEFINE_SPINLOCK(simple_ida_lock);
+/**
+ * idr_alloc_u32() - Allocate an ID.
+ * @idr: IDR handle.
+ * @ptr: Pointer to be associated with the new ID.
+ * @nextid: Pointer to an ID.
+ * @max: The maximum ID to allocate (inclusive).
+ * @gfp: Memory allocation flags.
+ *
+ * Allocates an unused ID in the range specified by @nextid and @max.
+ * Note that @max is inclusive whereas the @end parameter to idr_alloc()
+ * is exclusive.
+ *
+ * The caller should provide their own locking to ensure that two
+ * concurrent modifications to the IDR are not possible. Read-only
+ * accesses to the IDR may be done under the RCU read lock or may
+ * exclude simultaneous writers.
+ *
+ * Return: 0 if an ID was allocated, -ENOMEM if memory allocation failed,
+ * or -ENOSPC if no free IDs could be found. If an error occurred,
+ * @nextid is unchanged.
+ */
+int idr_alloc_u32(struct idr *idr, void *ptr, u32 *nextid,
+ unsigned long max, gfp_t gfp)
+{
+ unsigned long tmp = *nextid;
+ int ret = idr_alloc_ext(idr, ptr, &tmp, tmp, max + 1, gfp);
+ *nextid = tmp;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(idr_alloc_u32);
+
int idr_alloc_cmn(struct idr *idr, void *ptr, unsigned long *index,
unsigned long start, unsigned long end, gfp_t gfp,
bool ext)