md/raid6 algorithms: improve test program

It is always helpful to have a test tool in place if we implement
new data critical algorithms. So add some test routines to the raid6
checker that can prove if the new xor_syndrome() works as expected.

Run through all permutations of start/stop pages per algorithm and
simulate a xor_syndrome() assisted rmw run. After each rmw check if
the recovery algorithm still confirms that the stripe is fine.

Signed-off-by: Markus Stockhausen <stockhausen@collogia.de>
Signed-off-by: NeilBrown <neilb@suse.de>

1 files changed, 36 insertions, 15 deletions

diff --git a/lib/raid6/test/test.c b/lib/raid6/test/test.c
index 5a485b7a7d3c..3bebbabdb510 100644
--- a/lib/raid6/test/test.c
+++ b/lib/raid6/test/test.c
@@ -28,11 +28,11 @@ char *dataptrs[NDISKS];
 char data[NDISKS][PAGE_SIZE];
 char recovi[PAGE_SIZE], recovj[PAGE_SIZE];
 
-static void makedata(void)
+static void makedata(int start, int stop)
 {
         int i, j;
 
-        for (i = 0; i < NDISKS; i++) {
+        for (i = start; i <= stop; i++) {
                 for (j = 0; j < PAGE_SIZE; j++)
                         data[i][j] = rand();
 
@@ -91,34 +91,55 @@ int main(int argc, char *argv[])
 {
         const struct raid6_calls *const *algo;
         const struct raid6_recov_calls *const *ra;
-        int i, j;
+        int i, j, p1, p2;
         int err = 0;
 
-        makedata();
+        makedata(0, NDISKS-1);
 
         for (ra = raid6_recov_algos; *ra; ra++) {
                 if ((*ra)->valid  && !(*ra)->valid())
                         continue;
+
                 raid6_2data_recov = (*ra)->data2;
                 raid6_datap_recov = (*ra)->datap;
 
                 printf("using recovery %s\n", (*ra)->name);
 
                 for (algo = raid6_algos; *algo; algo++) {
-                        if (!(*algo)->valid || (*algo)->valid()) {
-                                raid6_call = **algo;
+                        if ((*algo)->valid && !(*algo)->valid())
+                                continue;
+
+                        raid6_call = **algo;
+
+                        /* Nuke syndromes */
+                        memset(data[NDISKS-2], 0xee, 2*PAGE_SIZE);
+
+                        /* Generate assumed good syndrome */
+                        raid6_call.gen_syndrome(NDISKS, PAGE_SIZE,
+                                                (void **)&dataptrs);
+
+                        for (i = 0; i < NDISKS-1; i++)
+                                for (j = i+1; j < NDISKS; j++)
+                                        err += test_disks(i, j);
+
+                        if (!raid6_call.xor_syndrome)
+                                continue;
+
+                        for (p1 = 0; p1 < NDISKS-2; p1++)
+                                for (p2 = p1; p2 < NDISKS-2; p2++) {
 
-                                /* Nuke syndromes */
-                                memset(data[NDISKS-2], 0xee, 2*PAGE_SIZE);
+                                        /* Simulate rmw run */
+                                        raid6_call.xor_syndrome(NDISKS, p1, p2, PAGE_SIZE,
+                                                                (void **)&dataptrs);
+                                        makedata(p1, p2);
+                                        raid6_call.xor_syndrome(NDISKS, p1, p2, PAGE_SIZE,
+                                                                (void **)&dataptrs);
 
-                                /* Generate assumed good syndrome */
-                                raid6_call.gen_syndrome(NDISKS, PAGE_SIZE,
-                                                        (void **)&dataptrs);
+                                        for (i = 0; i < NDISKS-1; i++)
+                                                for (j = i+1; j < NDISKS; j++)
+                                                        err += test_disks(i, j);
+                                }
 
-                                for (i = 0; i < NDISKS-1; i++)
-                                        for (j = i+1; j < NDISKS; j++)
-                                                err += test_disks(i, j);
-                        }
                 }
                 printf("\n");
         }