[PATCH 1/2] minmax: Add in_range_incl() for inclusive range checks

[Guru Das Srinagesh]

in_range(val, start, len) takes a start and a length, i.e. a half-open
range. Callers that instead have an inclusive [start, end] bound have
no ready helper function/macro to reach for and either hand-roll the
comparison or convert it to in_range()'s (start, len) form themselves.

Add in_range_incl(val, start, end), computing len as end - start + 1
and forwarding to in_range() so it inherits the existing 32-bit/64-bit
type dispatch rather than risking silent truncation from a fresh
hand-rolled comparison.

val, start and end are each assigned to a temporary variable before use,
so each is evaluated exactly once regardless of how many times it
appears in the expansion (matching swap()'s __tmp below).

Assisted-by: Claude-Code:claude-sonnet-5
Signed-off-by: Guru Das Srinagesh <linux@xxxxxxxxxxx>
---
 include/linux/minmax.h | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index a0158db54a04..71900d688a06 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -299,6 +299,27 @@ static inline bool in_range32(u32 val, u32 start, u32 len)
 	((sizeof(start) | sizeof(len) | sizeof(val)) <= sizeof(u32) ?	\
 		in_range32(val, start, len) : in_range64(val, start, len))
 
+/**
+ * in_range_incl - Determine if a value lies within an inclusive range.
+ * @val: Value to test.
+ * @start: First value in range.
+ * @end: Last value in range.
+ *
+ * @val, @start and @end are each evaluated exactly once.
+ *
+ * Same caveats as in_range() apply. In particular, if @end sits at the
+ * maximum value representable by the common type of @start and @end,
+ * "@end - @start + 1" wraps to 0, silently rejecting every @val instead
+ * of accepting all of them. Callers must ensure @end - @start + 1 does
+ * not overflow, and that @end >= @start.
+ */
+#define in_range_incl(val, start, end) ({			\
+	typeof(val) __val = (val);				\
+	typeof(start) __start = (start);			\
+	typeof(end) __end = (end);				\
+	in_range(__val, __start, __end - __start + 1);	\
+})
+
 /**
  * swap - swap values of @a and @b
  * @a: first value

-- 
2.55.0