[SRU][N][PATCH 1/3] s390/pai: export number of sysfs attribute files

[Massimiliano Pellizzer]

From: Thomas Richter <tmricht at linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/2121956

The number of sysfs files to be exported by the PAI device drivers
depends on the hardware version level. Use the value returned by
the hardware as the maximum number of counters to be exported
in the sysfs attribute tree.

Without the fix, older machine generation export counter names
based on paiXXXX_ctrnames static array info, which can be inaccurate,
as this array could also contain newer counter names in the
future.  This ensures proper pai counter sysfs attributes for
both newer generation and older generation processors.

Signed-off-by: Thomas Richter <tmricht at linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk at linux.ibm.com>
Signed-off-by: Heiko Carstens <hca at linux.ibm.com>
(cherry picked from commit d414f4ecb240b994cba8c9666def0a4b9c953601)
Signed-off-by: Massimiliano Pellizzer <massimiliano.pellizzer at canonical.com>
---
 arch/s390/kernel/perf_pai_crypto.c | 11 ++++++++---
 arch/s390/kernel/perf_pai_ext.c    | 11 ++++++++---
 2 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/arch/s390/kernel/perf_pai_crypto.c b/arch/s390/kernel/perf_pai_crypto.c
index 24b70a7fc6dba..2d18f3ce9540a 100644
--- a/arch/s390/kernel/perf_pai_crypto.c
+++ b/arch/s390/kernel/perf_pai_crypto.c
@@ -698,6 +698,12 @@ static int __init attr_event_init_one(struct attribute **attrs, int num)
 {
 	struct perf_pmu_events_attr *pa;
 
+	/* Index larger than array_size, no counter name available */
+	if (num >= ARRAY_SIZE(paicrypt_ctrnames)) {
+		attrs[num] = NULL;
+		return 0;
+	}
+
 	pa = kzalloc(sizeof(*pa), GFP_KERNEL);
 	if (!pa)
 		return -ENOMEM;
@@ -718,11 +724,10 @@ static int __init attr_event_init(void)
 	struct attribute **attrs;
 	int ret, i;
 
-	attrs = kmalloc_array(ARRAY_SIZE(paicrypt_ctrnames) + 1, sizeof(*attrs),
-			      GFP_KERNEL);
+	attrs = kmalloc_array(paicrypt_cnt + 2, sizeof(*attrs), GFP_KERNEL);
 	if (!attrs)
 		return -ENOMEM;
-	for (i = 0; i < ARRAY_SIZE(paicrypt_ctrnames); i++) {
+	for (i = 0; i <= paicrypt_cnt; i++) {
 		ret = attr_event_init_one(attrs, i);
 		if (ret) {
 			attr_event_free(attrs, i);
diff --git a/arch/s390/kernel/perf_pai_ext.c b/arch/s390/kernel/perf_pai_ext.c
index 24d2036b2c9e4..cf266797e2c1a 100644
--- a/arch/s390/kernel/perf_pai_ext.c
+++ b/arch/s390/kernel/perf_pai_ext.c
@@ -588,6 +588,12 @@ static int __init attr_event_init_one(struct attribute **attrs, int num)
 {
 	struct perf_pmu_events_attr *pa;
 
+	/* Index larger than array_size, no counter name available */
+	if (num >= ARRAY_SIZE(paiext_ctrnames)) {
+		attrs[num] = NULL;
+		return 0;
+	}
+
 	pa = kzalloc(sizeof(*pa), GFP_KERNEL);
 	if (!pa)
 		return -ENOMEM;
@@ -608,11 +614,10 @@ static int __init attr_event_init(void)
 	struct attribute **attrs;
 	int ret, i;
 
-	attrs = kmalloc_array(ARRAY_SIZE(paiext_ctrnames) + 1, sizeof(*attrs),
-			      GFP_KERNEL);
+	attrs = kmalloc_array(paiext_cnt + 2, sizeof(*attrs), GFP_KERNEL);
 	if (!attrs)
 		return -ENOMEM;
-	for (i = 0; i < ARRAY_SIZE(paiext_ctrnames); i++) {
+	for (i = 0; i <= paiext_cnt; i++) {
 		ret = attr_event_init_one(attrs, i);
 		if (ret) {
 			attr_event_free(attrs, i);
-- 
2.48.1