[PATCH v2] x86: Put the num_processors++ code in a more suitable position

[PATCH v2] x86: Put the num_processors++ code in a more suitable position

[Dou Liyang]

This code is just for correctness.

If checking the topology package map of apicid and cpu is failure,
it will stop generating the processor info for that apicid and the
disabled_cpus will plus one. However, the num-processors has already
been added one above. That may cause the number of processors incorrect.

Just put the num_processors++ code in the more suitable position.
it makes sure that the num-processors will not conflict with the
disabled_cpus.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
---
 arch/x86/kernel/apic/apic.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 50c95af..f3e9b2d 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2093,7 +2093,6 @@ int generic_processor_info(int apicid, int version)
 		return -EINVAL;
 	}
 
-	num_processors++;
 	if (apicid == boot_cpu_physical_apicid) {
 		/*
 		 * x86_bios_cpu_apicid is required to have processors listed
@@ -2116,10 +2115,13 @@ int generic_processor_info(int apicid, int version)
 
 		pr_warning("APIC: Package limit reached. Processor %d/0x%x ignored.\n",
 			   thiscpu, apicid);
+
 		disabled_cpus++;
 		return -ENOSPC;
 	}
 
+	num_processors++;
+
 	/*
 	 * Validate version
 	 */
-- 
2.5.5

[tip:x86/urgent] x86/apic: Fix num_processors value in case of failure

[tip-bot for Dou Liyang]

Commit-ID:  c291b015158577be533dd5a959dfc09bab119eed
Gitweb:     http://git.kernel.org/tip/c291b015158577be533dd5a959dfc09bab119eed
Author:     Dou Liyang <douly.fnst@cn.fujitsu.com>
AuthorDate: Wed, 7 Sep 2016 10:21:33 +0800
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 8 Sep 2016 08:11:03 +0200

x86/apic: Fix num_processors value in case of failure

If the topology package map check of the APIC ID and the CPU is a failure,
we don't generate the processor info for that APIC ID yet we increase
disabled_cpus by one - which is buggy.

Only increase num_processors once we are sure we don't fail.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1473214893-16481-1-git-send-email-douly.fnst@cn.fujitsu.com
[ Rewrote the changelog. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/kernel/apic/apic.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 50c95af..f3e9b2d 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -2093,7 +2093,6 @@ int generic_processor_info(int apicid, int version)
 		return -EINVAL;
 	}
 
-	num_processors++;
 	if (apicid == boot_cpu_physical_apicid) {
 		/*
 		 * x86_bios_cpu_apicid is required to have processors listed
@@ -2116,10 +2115,13 @@ int generic_processor_info(int apicid, int version)
 
 		pr_warning("APIC: Package limit reached. Processor %d/0x%x ignored.\n",
 			   thiscpu, apicid);
+
 		disabled_cpus++;
 		return -ENOSPC;
 	}
 
+	num_processors++;
+
 	/*
 	 * Validate version
 	 */