On Mon, Apr 19, 2010 at 8:14 PM, Tirumala Reddy Marri <tmarri@xxxxxxxx> wrote: > I understand the RAID-6 or GF(2) math. There is a test code crypto/async_tx/raid6test.c which make calls to async_gen_syncdrome() in turn calls raid6_int4_gen_syndrome(). I could not find which polynomial this code is using. > -Marri > > > -----Original Message----- > From: Michael Evans [mailto:mjevans1983@xxxxxxxxx] > Sent: Monday, April 19, 2010 6:55 PM > To: Tirumala Reddy Marri > Cc: linux-raid@xxxxxxxxxxxxxxx > Subject: Re: RAID-6 polynomial > > On Mon, Apr 19, 2010 at 4:44 PM, Tirumala Reddy Marri <tmarri@xxxxxxxx> wrote: >> What is the default polynomial to calculate RAID-6 syndrome in >> async_pq.c? Is it 0x11d ? >> Thanks in Advance, >> Marri >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > If you google "raid6 math" you'll get a result like this as the first result: > > http://kernel.org/pub/linux/kernel/people/hpa/raid6.pdf The > Mathematics of Raid 6 > Please bottom-reply for kernel.org lists. Would the hex you stated match the polynomial described in the 12 page (IIRC) PDF I linked? 0x11d would be, in binary, (h)100011101(l); I'm not sure if it presumes the 0th power being set or not. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
