From b5dceda1f7ef66cba6f8d766502f242a27f96e6d Mon Sep 17 00:00:00 2001 From: Anup Patel Date: Mon, 15 May 2017 10:34:52 +0530 Subject: lib/raid6: Add log-of-2 table for RAID6 HW requiring disk position The raid6_gfexp table represents {2}^n values for 0 <= n < 256. The Linux async_tx framework pass values from raid6_gfexp as coefficients for each source to prep_dma_pq() callback of DMA channel with PQ capability. This creates problem for RAID6 offload engines (such as Broadcom SBA) which take disk position (i.e. log of {2}) instead of multiplicative cofficients from raid6_gfexp table. This patch adds raid6_gflog table having log-of-2 value for any given x such that 0 <= x < 256. For any given disk coefficient x, the corresponding disk position is given by raid6_gflog[x]. The RAID6 offload engine driver can use this newly added raid6_gflog table to get disk position from multiplicative coefficient. Signed-off-by: Anup Patel Reviewed-by: Scott Branden Reviewed-by: Ray Jui Acked-by: Shaohua Li Signed-off-by: Vinod Koul --- include/linux/raid/pq.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/raid') diff --git a/include/linux/raid/pq.h b/include/linux/raid/pq.h index 4d57bbaaa1bf..30f945329818 100644 --- a/include/linux/raid/pq.h +++ b/include/linux/raid/pq.h @@ -142,6 +142,7 @@ int raid6_select_algo(void); extern const u8 raid6_gfmul[256][256] __attribute__((aligned(256))); extern const u8 raid6_vgfmul[256][32] __attribute__((aligned(256))); extern const u8 raid6_gfexp[256] __attribute__((aligned(256))); +extern const u8 raid6_gflog[256] __attribute__((aligned(256))); extern const u8 raid6_gfinv[256] __attribute__((aligned(256))); extern const u8 raid6_gfexi[256] __attribute__((aligned(256))); -- cgit v1.2.3-71-gd317