s390/cpum_sf: Ignore qsi() return code

qsi() executes the instruction qsi (query sample information)
and stores the result of the query in a sample information block
pointed to by the function argument. The instruction does not
change the condition code register. The return code is always
zero. No need to check for errors. Remove now unreferenced
macros PMC_FAILURE and RS_INIT_FAILURE_QSI.
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Acked-by: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/kernel/perf_cpum_sf.c

@@ -393,8 +393,8 @@ static void sfb_set_limits(unsigned long min, unsigned long max)
 	CPUM_SF_MAX_SDB = max;
 
 	memset(&si, 0, sizeof(si));
-	if (!qsi(&si))
-		CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes);
+	qsi(&si);
+	CPUM_SF_SDB_DIAG_FACTOR = DIV_ROUND_UP(si.dsdes, si.bsdes);
 }
 
 static unsigned long sfb_max_limit(struct hw_perf_event *hwc)
@@ -607,18 +607,14 @@ static DEFINE_MUTEX(pmc_reserve_mutex);
 
 #define PMC_INIT      0
 #define PMC_RELEASE   1
-#define PMC_FAILURE   2
 static void setup_pmc_cpu(void *flags)
 {
 	struct cpu_hw_sf *cpuhw = this_cpu_ptr(&cpu_hw_sf);
-	int err = 0;
 
 	switch (*((int *)flags)) {
 	case PMC_INIT:
 		memset(cpuhw, 0, sizeof(*cpuhw));
-		err = qsi(&cpuhw->qsi);
-		if (err)
-			break;
+		qsi(&cpuhw->qsi);
 		cpuhw->flags |= PMU_F_RESERVED;
 		sf_disable();
 		break;
@@ -628,10 +624,6 @@ static void setup_pmc_cpu(void *flags)
 		deallocate_buffers(cpuhw);
 		break;
 	}
-	if (err) {
-		*((int *)flags) |= PMC_FAILURE;
-		pr_err("Switching off the sampling facility failed with rc %i\n", err);
-	}
 }
 
 static void release_pmc_hardware(void)
@@ -642,18 +634,12 @@ static void release_pmc_hardware(void)
 	on_each_cpu(setup_pmc_cpu, &flags, 1);
 }
 
-static int reserve_pmc_hardware(void)
+static void reserve_pmc_hardware(void)
 {
 	int flags = PMC_INIT;
 
 	on_each_cpu(setup_pmc_cpu, &flags, 1);
-	if (flags & PMC_FAILURE) {
-		release_pmc_hardware();
-		return -ENODEV;
-	}
 	irq_subclass_register(IRQ_SUBCLASS_MEASUREMENT_ALERT);
-
-	return 0;
 }
 
 static void hw_perf_event_destroy(struct perf_event *event)
@@ -828,13 +814,10 @@ static int __hw_perf_event_init(struct perf_event *event)
 	/* Reserve CPU-measurement sampling facility */
 	mutex_lock(&pmc_reserve_mutex);
 	if (!refcount_inc_not_zero(&num_events)) {
-		err = reserve_pmc_hardware();
-		if (!err)
-			refcount_set(&num_events, 1);
+		reserve_pmc_hardware();
+		refcount_set(&num_events, 1);
 	}
 	mutex_unlock(&pmc_reserve_mutex);
-	if (err)
-		goto out;
 	event->destroy = hw_perf_event_destroy;
 
 	/* Access per-CPU sampling information (query sampling info) */
@@ -848,9 +831,9 @@ static int __hw_perf_event_init(struct perf_event *event)
 	 */
 	memset(&si, 0, sizeof(si));
 	cpuhw = NULL;
-	if (event->cpu == -1)
+	if (event->cpu == -1) {
 		qsi(&si);
-	else {
+	} else {
 		/* Event is pinned to a particular CPU, retrieve the per-CPU
 		 * sampling structure for accessing the CPU-specific QSI.
 		 */
@@ -1061,21 +1044,18 @@ static void cpumsf_pmu_disable(struct pmu *pmu)
 		return;
 	}
 
-	/* Save state of TEAR and DEAR register contents */
-	err = qsi(&si);
-	if (!err) {
-		/* TEAR/DEAR values are valid only if the sampling facility is
-		 * enabled.  Note that cpumsf_pmu_disable() might be called even
-		 * for a disabled sampling facility because cpumsf_pmu_enable()
-		 * controls the enable/disable state.
-		 */
-		if (si.es) {
-			cpuhw->lsctl.tear = si.tear;
-			cpuhw->lsctl.dear = si.dear;
-		}
-	} else
-		debug_sprintf_event(sfdbg, 3, "%s: qsi() failed with err %i\n",
-				    __func__, err);
+	/*
+	 * Save state of TEAR and DEAR register contents.
+	 * TEAR/DEAR values are valid only if the sampling facility is
+	 * enabled.  Note that cpumsf_pmu_disable() might be called even
+	 * for a disabled sampling facility because cpumsf_pmu_enable()
+	 * controls the enable/disable state.
+	 */
+	qsi(&si);
+	if (si.es) {
+		cpuhw->lsctl.tear = si.tear;
+		cpuhw->lsctl.dear = si.dear;
+	}
 
 	cpuhw->flags &= ~PMU_F_ENABLED;
 }
@@ -1869,8 +1849,7 @@ static int cpumsf_pmu_check_period(struct perf_event *event, u64 value)
 
 	memset(&si, 0, sizeof(si));
 	if (event->cpu == -1) {
-		if (qsi(&si))
-			return -ENODEV;
+		qsi(&si);
 	} else {
 		/* Event is pinned to a particular CPU, retrieve the per-CPU
 		 * sampling structure for accessing the CPU-specific QSI.
@@ -2210,10 +2189,12 @@ static const struct kernel_param_ops param_ops_sfb_size = {
 	.get = param_get_sfb_size,
 };
 
-#define RS_INIT_FAILURE_QSI	  0x0001
-#define RS_INIT_FAILURE_BSDES	  0x0002
-#define RS_INIT_FAILURE_ALRT	  0x0003
-#define RS_INIT_FAILURE_PERF	  0x0004
+enum {
+	RS_INIT_FAILURE_BSDES	= 2,	/* Bad basic sampling size */
+	RS_INIT_FAILURE_ALRT	= 3,	/* IRQ registration failure */
+	RS_INIT_FAILURE_PERF	= 4	/* PMU registration failure */
+};
+
 static void __init pr_cpumsf_err(unsigned int reason)
 {
 	pr_err("Sampling facility support for perf is not available: "
@@ -2229,11 +2210,7 @@ static int __init init_cpum_sampling_pmu(void)
 		return -ENODEV;
 
 	memset(&si, 0, sizeof(si));
-	if (qsi(&si)) {
-		pr_cpumsf_err(RS_INIT_FAILURE_QSI);
-		return -ENODEV;
-	}
-
+	qsi(&si);
 	if (!si.as && !si.ad)
 		return -ENODEV;