Re: [RFC] net/hsr: Add support for IEC 62439-3 High-availability Seamless Redundancy

On Tue, 27 Mar 2012 15:20:45 +0200
Arvid Brodin [off-list ref] wrote:

+config NONSTANDARD_HSR
+	bool "HSR: Use efficient tag (breaks HSR standard, read help!)"
+	depends on HSR
+	---help---
+	  The HSR standard specifies a 6-byte HSR tag to be inserted into the
+	  transmitted network frames. This breaks the 32-bit alignment that the
+	  Linux network stack relies on, and would cause kernel panics on
+	  certain architectures. To avoid this, the whole frame payload is
+	  memmoved 2 bytes on reception on these architectures - which is very
+	  inefficient!

This option won't fly. Don't do it.
If you need to copy/realign packets on some architecture the stack
should be changed to handle it.