Le 26/02/2024 à 12:47, Russell King (Oracle) a écrit : > On Mon, Feb 26, 2024 at 11:34:51AM +0000, Christophe Leroy wrote: >> Le 23/02/2024 à 23:11, Charlie Jenkins a écrit : >>> The test cases for ip_fast_csum and csum_ipv6_magic were not properly >>> aligning the IP header, which were causing failures on architectures >>> that do not support misaligned accesses like some ARM platforms. To >>> solve this, align the data along (14 + NET_IP_ALIGN) bytes which is the >>> standard alignment of an IP header and must be supported by the >>> architecture. >> >> I'm still wondering what we are really trying to fix here. >> >> All other tests are explicitely testing that it works with any alignment. >> >> Shouldn't ip_fast_csum() and csum_ipv6_magic() work for any alignment as >> well ? I would expect it, I see no comment in arm code which explicits >> that assumption around those functions. > > No, these functions are explicitly *not* designed to be used with any > alignment. They are for 16-bit alignment only. > > I'm not sure where the idea that "any alignment" has come from, but it's > never been the case AFAIK that we've supported that - or if we do now, > that's something which has crept in under the radar. > Ok, 16-bit is fine for me, then there is no need to require a (14 + NET_IP_ALIGN) ie a 16-bytes (128-bit) alignment as this patch is doing. Christophe
