On Mon, Jun 24, 2019 at 03:08:55PM +0000, Robert Richter wrote: > The grain in edac is defined as "minimum granularity for an error > report, in bytes". The following calculation of the grain_bits in > edac_mc is wrong: > > grain_bits = fls_long(e->grain) + 1; > > Where grain_bits is defined as: > > grain = 1 << grain_bits > > Example: > > grain = 8 # 64 bit (8 bytes) > grain_bits = fls_long(8) + 1 > grain_bits = 4 + 1 = 5 > > grain = 1 << grain_bits > grain = 1 << 5 = 32 > > Replacing it with the correct calculation: > > grain_bits = fls_long(e->grain - 1); > > The example gives now: > > grain_bits = fls_long(8 - 1) > grain_bits = fls_long(8 - 1) > grain_bits = 3 > > grain = 1 << 3 = 8 > > Note: We need to check if the hardware reports a reasonable grain != 0 > and fallback with a warn_once and 1 byte granularity otherwise. > > Signed-off-by: Robert Richter <rrich...@marvell.com> > --- > drivers/edac/edac_mc.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-)
Applied to the new EDAC repo: https://git.kernel.org/pub/scm/linux/kernel/git/ras/ras.git/log/?h=edac-for-next Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.
