/* * RAID-6 data recovery in dual failure mode based on the XC instruction. * * Copyright IBM Corp. 2016 * Author(s): Martin Schwidefsky */ #include #include static inline void xor_block(u8 *p1, u8 *p2) { typedef struct { u8 _[256]; } addrtype; asm volatile( " xc 0(256,%[p1]),0(%[p2])\n" : "+m" (*(addrtype *) p1) : "m" (*(addrtype *) p2), [p1] "a" (p1), [p2] "a" (p2) : "cc"); } /* Recover two failed data blocks. */ static void raid6_2data_recov_s390xc(int disks, size_t bytes, int faila, int failb, void **ptrs) { u8 *p, *q, *dp, *dq; const u8 *pbmul; /* P multiplier table for B data */ const u8 *qmul; /* Q multiplier table (for both) */ int i; p = (u8 *)ptrs[disks-2]; q = (u8 *)ptrs[disks-1]; /* Compute syndrome with zero for the missing data pages Use the dead data pages as temporary storage for delta p and delta q */ dp = (u8 *)ptrs[faila]; ptrs[faila] = (void *)raid6_empty_zero_page; ptrs[disks-2] = dp; dq = (u8 *)ptrs[failb]; ptrs[failb] = (void *)raid6_empty_zero_page; ptrs[disks-1] = dq; raid6_call.gen_syndrome(disks, bytes, ptrs); /* Restore pointer table */ ptrs[faila] = dp; ptrs[failb] = dq; ptrs[disks-2] = p; ptrs[disks-1] = q; /* Now, pick the proper data tables */ pbmul = raid6_gfmul[raid6_gfexi[failb-faila]]; qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]^raid6_gfexp[failb]]]; /* Now do it... */ while (bytes) { xor_block(dp, p); xor_block(dq, q); for (i = 0; i < 256; i++) dq[i] = pbmul[dp[i]] ^ qmul[dq[i]]; xor_block(dp, dq); p += 256; q += 256; dp += 256; dq += 256; bytes -= 256; } } /* Recover failure of one data block plus the P block */ static void raid6_datap_recov_s390xc(int disks, size_t bytes, int faila, void **ptrs) { u8 *p, *q, *dq; const u8 *qmul; /* Q multiplier table */ int i; p = (u8 *)ptrs[disks-2]; q = (u8 *)ptrs[disks-1]; /* Compute syndrome with zero for the missing data page Use the dead data page as temporary storage for delta q */ dq = (u8 *)ptrs[faila]; ptrs[faila] = (void *)raid6_empty_zero_page; ptrs[disks-1] = dq; raid6_call.gen_syndrome(disks, bytes, ptrs); /* Restore pointer table */ ptrs[faila] = dq; ptrs[disks-1] = q; /* Now, pick the proper data tables */ qmul = raid6_gfmul[raid6_gfinv[raid6_gfexp[faila]]]; /* Now do it... */ while (bytes) { xor_block(dq, q); for (i = 0; i < 256; i++) dq[i] = qmul[dq[i]]; xor_block(p, dq); p += 256; q += 256; dq += 256; bytes -= 256; } } const struct raid6_recov_calls raid6_recov_s390xc = { .data2 = raid6_2data_recov_s390xc, .datap = raid6_datap_recov_s390xc, .valid = NULL, .name = "s390xc", .priority = 1, }; 40f397bcc6901fb88752a'>net/tipc/node.h

Age	Commit message (Expand)	Author	Files	Lines