xarray: fix kerneldoc for __xa_cmpxchg

Fix the documentation for __xa_cmpxchg to actually describe the
cmpxch-like semantics correctly, based on the version for xa_cmpxchg.

Link: https://lkml.kernel.org/r/20250507051656.3900864-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/xarray.c b/lib/xarray.c
index 9644b18af18d1739ab6461f87312c6a2c432a6b7..76dde3a1cacf5f17a2c4d9141e17bb82a2a9b2e8 100644 (file)
--- a/lib/xarray.c
+++ b/lib/xarray.c
@@ -1742,20 +1742,23 @@ static inline void *__xa_cmpxchg_raw(struct xarray *xa, unsigned long index,
                        void *old, void *entry, gfp_t gfp);
 
 /**
- * __xa_cmpxchg() - Store this entry in the XArray.
+ * __xa_cmpxchg() - Conditionally replace an entry in the XArray.
  * @xa: XArray.
  * @index: Index into array.
  * @old: Old value to test against.
- * @entry: New entry.
+ * @entry: New value to place in array.
  * @gfp: Memory allocation flags.
  *
  * You must already be holding the xa_lock when calling this function.
  * It will drop the lock if needed to allocate memory, and then reacquire
  * it afterwards.
  *
+ * If the entry at @index is the same as @old, replace it with @entry.
+ * If the return value is equal to @old, then the exchange was successful.
+ *
  * Context: Any context.  Expects xa_lock to be held on entry.  May
  * release and reacquire xa_lock if @gfp flags permit.
- * Return: The old entry at this index or xa_err() if an error happened.
+ * Return: The old value at this index or xa_err() if an error happened.
  */
 void *__xa_cmpxchg(struct xarray *xa, unsigned long index,
                        void *old, void *entry, gfp_t gfp)