Documentation/maintainer-tip: Add C++ tail comments exception

Document when C++-style, tail comments should be used.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240130193102.GEZblOdor_bzoVhT0f@fat_crate.local

diff --git a/Documentation/process/maintainer-tip.rst b/Documentation/process/maintainer-tip.rst
index 799359231b7f29a288bad785bc57656b1b06b8a2..497bb39727c8b05808720a5b41fbeca68ab81681 100644 (file)
--- a/Documentation/process/maintainer-tip.rst
+++ b/Documentation/process/maintainer-tip.rst
@@ -480,7 +480,7 @@ Multi-line comments::
         * Larger multi-line comments should be split into paragraphs.
         */
 
-No tail comments:
+No tail comments (see below):
 
   Please refrain from using tail comments. Tail comments disturb the
   reading flow in almost all contexts, but especially in code::
@@ -501,6 +501,34 @@ No tail comments:
        /* This magic initialization needs a comment. Maybe not? */
        seed = MAGIC_CONSTANT;
 
+  Use C++ style, tail comments when documenting structs in headers to
+  achieve a more compact layout and better readability::
+
+        // eax
+        u32     x2apic_shift    :  5, // Number of bits to shift APIC ID right
+                                      // for the topology ID at the next level
+                                : 27; // Reserved
+        // ebx
+        u32     num_processors  : 16, // Number of processors at current level
+                                : 16; // Reserved
+
+  versus::
+
+       /* eax */
+               /*
+                * Number of bits to shift APIC ID right for the topology ID
+                * at the next level
+                */
+         u32     x2apic_shift    :  5,
+                /* Reserved */
+                                : 27;
+
+       /* ebx */
+               /* Number of processors at current level */
+       u32     num_processors  : 16,
+               /* Reserved */
+                               : 16;
+
 Comment the important things:
 
   Comments should be added where the operation is not obvious. Documenting