acpi, nfit, libnvdimm: fix interleave set cookie calculation (64-bit …

…comparison) While reviewing the -stable patch for commit 86ef58a "nfit, libnvdimm: fix interleave set cookie calculation" Ben noted: "This is returning an int, thus it's effectively doing a 32-bit comparison and not the 64-bit comparison you say is needed." Update the compare operation to be immune to this integer demotion problem. Cc: <[email protected]> Cc: Nicholas Moulin <[email protected]> Fixes: 86ef58a ("nfit, libnvdimm: fix interleave set cookie calculation") Reported-by: Ben Hutchings <[email protected]> Signed-off-by: Dan Williams <[email protected]>
coreos · Mar 28, 2017 · b03b99a · b03b99a
1 parent c02ed2e
commit b03b99a
Showing 1 changed file with 5 additions and 1 deletion.
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
@@ -1617,7 +1617,11 @@ static int cmp_map(const void *m0, const void *m1)
 	const struct nfit_set_info_map *map0 = m0;
 	const struct nfit_set_info_map *map1 = m1;
 
-	return map0->region_offset - map1->region_offset;
+	if (map0->region_offset < map1->region_offset)
+		return -1;
+	else if (map0->region_offset > map1->region_offset)
+		return 1;
+	return 0;
 }
 
 /* Retrieve the nth entry referencing this spa */