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From:   Nadav Amit <namit@vmware.com>
To:     Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>
Cc:     linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        Borislav Petkov <bp@alien8.de>, x86@kernel.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Nadav Amit <namit@vmware.com>,
        Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>,
        Tony Luck <tony.luck@intel.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 1/9] smp: Remove smp_call_function() and on_each_cpu() return values
Date:   Wed, 12 Jun 2019 23:48:05 -0700
Message-Id: <20190613064813.8102-2-namit@vmware.com>
In-Reply-To: <20190613064813.8102-1-namit@vmware.com>
References: <20190613064813.8102-1-namit@vmware.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The return value is fixed. Remove it and amend the callers.

Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
---
 arch/alpha/kernel/smp.c      | 19 +++++--------------
 arch/alpha/oprofile/common.c |  6 +++---
 arch/ia64/kernel/perfmon.c   | 12 ++----------
 arch/ia64/kernel/uncached.c  |  8 ++++----
 arch/x86/lib/cache-smp.c     |  3 ++-
 drivers/char/agp/generic.c   |  3 +--
 include/linux/smp.h          |  7 +++----
 kernel/smp.c                 | 10 +++-------
 kernel/up.c                  |  3 +--
 9 files changed, 24 insertions(+), 47 deletions(-)

diff --git a/arch/alpha/kernel/smp.c b/arch/alpha/kernel/smp.c
index d0dccae53ba9..5f90df30be20 100644
--- a/arch/alpha/kernel/smp.c
+++ b/arch/alpha/kernel/smp.c
@@ -614,8 +614,7 @@ void
 smp_imb(void)
 {
 	/* Must wait other processors to flush their icache before continue. */
-	if (on_each_cpu(ipi_imb, NULL, 1))
-		printk(KERN_CRIT "smp_imb: timed out\n");
+	on_each_cpu(ipi_imb, NULL, 1);
 }
 EXPORT_SYMBOL(smp_imb);
 
@@ -630,9 +629,7 @@ flush_tlb_all(void)
 {
 	/* Although we don't have any data to pass, we do want to
 	   synchronize with the other processors.  */
-	if (on_each_cpu(ipi_flush_tlb_all, NULL, 1)) {
-		printk(KERN_CRIT "flush_tlb_all: timed out\n");
-	}
+	on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 }
 
 #define asn_locked() (cpu_data[smp_processor_id()].asn_lock)
@@ -667,9 +664,7 @@ flush_tlb_mm(struct mm_struct *mm)
 		}
 	}
 
-	if (smp_call_function(ipi_flush_tlb_mm, mm, 1)) {
-		printk(KERN_CRIT "flush_tlb_mm: timed out\n");
-	}
+	smp_call_function(ipi_flush_tlb_mm, mm, 1);
 
 	preempt_enable();
 }
@@ -720,9 +715,7 @@ flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
 	data.mm = mm;
 	data.addr = addr;
 
-	if (smp_call_function(ipi_flush_tlb_page, &data, 1)) {
-		printk(KERN_CRIT "flush_tlb_page: timed out\n");
-	}
+	smp_call_function(ipi_flush_tlb_page, &data, 1);
 
 	preempt_enable();
 }
@@ -772,9 +765,7 @@ flush_icache_user_range(struct vm_area_struct *vma, struct page *page,
 		}
 	}
 
-	if (smp_call_function(ipi_flush_icache_page, mm, 1)) {
-		printk(KERN_CRIT "flush_icache_page: timed out\n");
-	}
+	smp_call_function(ipi_flush_icache_page, mm, 1);
 
 	preempt_enable();
 }
diff --git a/arch/alpha/oprofile/common.c b/arch/alpha/oprofile/common.c
index 310a4ce1dccc..1b1259c7d7d1 100644
--- a/arch/alpha/oprofile/common.c
+++ b/arch/alpha/oprofile/common.c
@@ -65,7 +65,7 @@ op_axp_setup(void)
 	model->reg_setup(&reg, ctr, &sys);
 
 	/* Configure the registers on all cpus.  */
-	(void)smp_call_function(model->cpu_setup, &reg, 1);
+	smp_call_function(model->cpu_setup, &reg, 1);
 	model->cpu_setup(&reg);
 	return 0;
 }
@@ -86,7 +86,7 @@ op_axp_cpu_start(void *dummy)
 static int
 op_axp_start(void)
 {
-	(void)smp_call_function(op_axp_cpu_start, NULL, 1);
+	smp_call_function(op_axp_cpu_start, NULL, 1);
 	op_axp_cpu_start(NULL);
 	return 0;
 }
@@ -101,7 +101,7 @@ op_axp_cpu_stop(void *dummy)
 static void
 op_axp_stop(void)
 {
-	(void)smp_call_function(op_axp_cpu_stop, NULL, 1);
+	smp_call_function(op_axp_cpu_stop, NULL, 1);
 	op_axp_cpu_stop(NULL);
 }
 
diff --git a/arch/ia64/kernel/perfmon.c b/arch/ia64/kernel/perfmon.c
index 58a6337c0690..7c52bd2695a2 100644
--- a/arch/ia64/kernel/perfmon.c
+++ b/arch/ia64/kernel/perfmon.c
@@ -6390,11 +6390,7 @@ pfm_install_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
 	}
 
 	/* save the current system wide pmu states */
-	ret = on_each_cpu(pfm_alt_save_pmu_state, NULL, 1);
-	if (ret) {
-		DPRINT(("on_each_cpu() failed: %d\n", ret));
-		goto cleanup_reserve;
-	}
+	on_each_cpu(pfm_alt_save_pmu_state, NULL, 1);
 
 	/* officially change to the alternate interrupt handler */
 	pfm_alt_intr_handler = hdl;
@@ -6421,7 +6417,6 @@ int
 pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
 {
 	int i;
-	int ret;
 
 	if (hdl == NULL) return -EINVAL;
 
@@ -6435,10 +6430,7 @@ pfm_remove_alt_pmu_interrupt(pfm_intr_handler_desc_t *hdl)
 
 	pfm_alt_intr_handler = NULL;
 
-	ret = on_each_cpu(pfm_alt_restore_pmu_state, NULL, 1);
-	if (ret) {
-		DPRINT(("on_each_cpu() failed: %d\n", ret));
-	}
+	on_each_cpu(pfm_alt_restore_pmu_state, NULL, 1);
 
 	for_each_online_cpu(i) {
 		pfm_unreserve_session(NULL, 1, i);
diff --git a/arch/ia64/kernel/uncached.c b/arch/ia64/kernel/uncached.c
index edcdfc149311..16c6d377c502 100644
--- a/arch/ia64/kernel/uncached.c
+++ b/arch/ia64/kernel/uncached.c
@@ -121,8 +121,8 @@ static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
 	status = ia64_pal_prefetch_visibility(PAL_VISIBILITY_PHYSICAL);
 	if (status == PAL_VISIBILITY_OK_REMOTE_NEEDED) {
 		atomic_set(&uc_pool->status, 0);
-		status = smp_call_function(uncached_ipi_visibility, uc_pool, 1);
-		if (status || atomic_read(&uc_pool->status))
+		smp_call_function(uncached_ipi_visibility, uc_pool, 1);
+		if (atomic_read(&uc_pool->status))
 			goto failed;
 	} else if (status != PAL_VISIBILITY_OK)
 		goto failed;
@@ -143,8 +143,8 @@ static int uncached_add_chunk(struct uncached_pool *uc_pool, int nid)
 	if (status != PAL_STATUS_SUCCESS)
 		goto failed;
 	atomic_set(&uc_pool->status, 0);
-	status = smp_call_function(uncached_ipi_mc_drain, uc_pool, 1);
-	if (status || atomic_read(&uc_pool->status))
+	smp_call_function(uncached_ipi_mc_drain, uc_pool, 1);
+	if (atomic_read(&uc_pool->status))
 		goto failed;
 
 	/*
diff --git a/arch/x86/lib/cache-smp.c b/arch/x86/lib/cache-smp.c
index 1811fa4a1b1a..7c48ff4ae8d1 100644
--- a/arch/x86/lib/cache-smp.c
+++ b/arch/x86/lib/cache-smp.c
@@ -15,6 +15,7 @@ EXPORT_SYMBOL(wbinvd_on_cpu);
 
 int wbinvd_on_all_cpus(void)
 {
-	return on_each_cpu(__wbinvd, NULL, 1);
+	on_each_cpu(__wbinvd, NULL, 1);
+	return 0;
 }
 EXPORT_SYMBOL(wbinvd_on_all_cpus);
diff --git a/drivers/char/agp/generic.c b/drivers/char/agp/generic.c
index 658664a5a5aa..df1edb5ec0ad 100644
--- a/drivers/char/agp/generic.c
+++ b/drivers/char/agp/generic.c
@@ -1311,8 +1311,7 @@ static void ipi_handler(void *null)
 
 void global_cache_flush(void)
 {
-	if (on_each_cpu(ipi_handler, NULL, 1) != 0)
-		panic(PFX "timed out waiting for the other CPUs!\n");
+	on_each_cpu(ipi_handler, NULL, 1);
 }
 EXPORT_SYMBOL(global_cache_flush);
 
diff --git a/include/linux/smp.h b/include/linux/smp.h
index a56f08ff3097..bb8b451ab01f 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -35,7 +35,7 @@ int smp_call_function_single(int cpuid, smp_call_func_t func, void *info,
 /*
  * Call a function on all processors
  */
-int on_each_cpu(smp_call_func_t func, void *info, int wait);
+void on_each_cpu(smp_call_func_t func, void *info, int wait);
 
 /*
  * Call a function on processors specified by mask, which might include
@@ -101,7 +101,7 @@ extern void smp_cpus_done(unsigned int max_cpus);
 /*
  * Call a function on all other processors
  */
-int smp_call_function(smp_call_func_t func, void *info, int wait);
+void smp_call_function(smp_call_func_t func, void *info, int wait);
 void smp_call_function_many(const struct cpumask *mask,
 			    smp_call_func_t func, void *info, bool wait);
 
@@ -144,9 +144,8 @@ static inline void smp_send_stop(void) { }
  *	These macros fold the SMP functionality into a single CPU system
  */
 #define raw_smp_processor_id()			0
-static inline int up_smp_call_function(smp_call_func_t func, void *info)
+static inline void up_smp_call_function(smp_call_func_t func, void *info)
 {
-	return 0;
 }
 #define smp_call_function(func, info, wait) \
 			(up_smp_call_function(func, info))
diff --git a/kernel/smp.c b/kernel/smp.c
index d155374632eb..708d2ac1db72 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -487,13 +487,11 @@ EXPORT_SYMBOL(smp_call_function_many);
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
  */
-int smp_call_function(smp_call_func_t func, void *info, int wait)
+void smp_call_function(smp_call_func_t func, void *info, int wait)
 {
 	preempt_disable();
 	smp_call_function_many(cpu_online_mask, func, info, wait);
 	preempt_enable();
-
-	return 0;
 }
 EXPORT_SYMBOL(smp_call_function);
 
@@ -594,18 +592,16 @@ void __init smp_init(void)
  * early_boot_irqs_disabled is set.  Use local_irq_save/restore() instead
  * of local_irq_disable/enable().
  */
-int on_each_cpu(void (*func) (void *info), void *info, int wait)
+void on_each_cpu(void (*func) (void *info), void *info, int wait)
 {
 	unsigned long flags;
-	int ret = 0;
 
 	preempt_disable();
-	ret = smp_call_function(func, info, wait);
+	smp_call_function(func, info, wait);
 	local_irq_save(flags);
 	func(info);
 	local_irq_restore(flags);
 	preempt_enable();
-	return ret;
 }
 EXPORT_SYMBOL(on_each_cpu);
 
diff --git a/kernel/up.c b/kernel/up.c
index 483c9962c999..862b460ab97a 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -35,14 +35,13 @@ int smp_call_function_single_async(int cpu, call_single_data_t *csd)
 }
 EXPORT_SYMBOL(smp_call_function_single_async);
 
-int on_each_cpu(smp_call_func_t func, void *info, int wait)
+void on_each_cpu(smp_call_func_t func, void *info, int wait)
 {
 	unsigned long flags;
 
 	local_irq_save(flags);
 	func(info);
 	local_irq_restore(flags);
-	return 0;
 }
 EXPORT_SYMBOL(on_each_cpu);
 
-- 
2.20.1