[PATCH v2 07/19] maple_tree: Clarify comments on mas_nomem()

["Liam R. Howlett (Oracle)" <liam@infradead.org>]

When an allocation completely fails, the return is false.  If the
allocation succeeds or partially succeeds, return true to indicate a
retry of the operation.  Note that since the lock may have been dropped,
the operation is retried from the start - including potentially
allocating more memory.

Signed-off-by: Liam R. Howlett (Oracle) <liam@infradead.org>
---
 lib/maple_tree.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 97849db132e7a..3886b856d6e3a 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -5676,10 +5676,11 @@ EXPORT_SYMBOL_GPL(mas_erase);
 
 /**
  * mas_nomem() - Check if there was an error allocating and do the allocation
- * if necessary If there are allocations, then free them.
+ * if necessary.
+ *
  * @mas: The maple state
  * @gfp: The GFP_FLAGS to use for allocations
- * Return: true on allocation, false otherwise.
+ * Return: False on no memory.  True otherwise (partial success as well)
  */
 bool mas_nomem(struct ma_state *mas, gfp_t gfp)
 	__must_hold(mas->tree->ma_lock)
@@ -5695,6 +5696,10 @@ bool mas_nomem(struct ma_state *mas, gfp_t gfp)
 		mas_alloc_nodes(mas, gfp);
 	}
 
+	/*
+	 * Return false on zero forward progress.  Partial allocations are kept
+	 * so the retry path will attempt to get the rest.
+	 */
 	if (!mas->sheaf && !mas->alloc)
 		return false;
 
-- 
2.47.3