[PATCH] s390/pai: Reduce excessive debug feature size

[Heiko Carstens <hca@linux.ibm.com>]

The pai debug feature is registered with 256 areas, where each area
contains 32 pages. This sums up to a total of 32MiB. The code does not use
any debug exceptions, which means that 255 of those areas are never
used. In addition all existing debug feature calls have a lower level (5)
than the default level (3).

This in turn means that without user interaction the debug feature is
unused.

Reduce the number of areas to 1, and also reduce the number of pages for
the remaining area to 1. Since user interaction is required, the user can
also increase the size of the remaining area, instead of wasting memory by
default.

This reduces the total size of the debug feature to 4KiB.

Fixes: a3f8423622ef ("s390/pai_crypto: Add PAI crypto characteristics table for parameters")
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/kernel/perf_pai.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/kernel/perf_pai.c b/arch/s390/kernel/perf_pai.c
index cdb8006220ca..ab76ed7ad791 100644
--- a/arch/s390/kernel/perf_pai.c
+++ b/arch/s390/kernel/perf_pai.c
@@ -1221,7 +1221,7 @@ static int __init paipmu_setup(void)
 static int __init pai_init(void)
 {
 	/* Setup s390dbf facility */
-	paidbg = debug_register("pai", 32, 256, 128);
+	paidbg = debug_register("pai", 1, 1, 128);
 	if (!paidbg) {
 		pr_err("Registration of s390dbf pai failed\n");
 		return -ENOMEM;
-- 
2.53.0