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authorAnup Patel <anup.patel@broadcom.com>2017-05-15 08:04:52 +0300
committerVinod Koul <vinod.koul@intel.com>2017-05-16 07:31:57 +0300
commitb5dceda1f7ef66cba6f8d766502f242a27f96e6d (patch)
treeda070d8503d0697d9ffff58f2a819837c2baa9ef /include/linux/raid
parent2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff)
downloadlinux-b5dceda1f7ef66cba6f8d766502f242a27f96e6d.tar.xz
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 <anup.patel@broadcom.com> Reviewed-by: Scott Branden <scott.branden@broadcom.com> Reviewed-by: Ray Jui <ray.jui@broadcom.com> Acked-by: Shaohua Li <shli@fb.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'include/linux/raid')
-rw-r--r--include/linux/raid/pq.h1
1 files changed, 1 insertions, 0 deletions
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)));