[PATCH 0/4] x86/smpboot: Fine-tuning for smp_init_package_map()

[PATCH 0/4] x86/smpboot: Fine-tuning for smp_init_package_map()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 5 Sep 2016 09:50:05 +0200

A few update suggestions were taken into account
from static source code analysis.

Markus Elfring (4):
  Use kmalloc_array()
  Return directly after a failed kmalloc_array()
  Replace one kzalloc() call by kcalloc()
  Return directly after a failed kcalloc()

 arch/x86/kernel/smpboot.c | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

-- 
2.9.3

[PATCH 1/4] x86/smpboot: Use kmalloc_array() in smp_init_package_map()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 5 Sep 2016 08:30:20 +0200

* A multiplication for the size determination of a memory allocation
  indicated that an array data structure should be processed.
  Thus use the corresponding function "kmalloc_array".

  This issue was detected by using the Coccinelle software.

* Replace the specification of a data type by a pointer dereference
  to make the corresponding size determination a bit safer according to
  the Linux coding style convention.

* Move a calculation for one function call.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 arch/x86/kernel/smpboot.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 3878725..36cf27e 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -349,9 +349,12 @@ static void __init smp_init_package_map(void)
 	 * package can be smaller than the actual used apic ids.
 	 */
 	max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
-	size = max_physical_pkg_id * sizeof(unsigned int);
-	physical_to_logical_pkg = kmalloc(size, GFP_KERNEL);
-	memset(physical_to_logical_pkg, 0xff, size);
+	physical_to_logical_pkg = kmalloc_array(max_physical_pkg_id,
+						sizeof(*physical_to_logical_pkg),
+						GFP_KERNEL);
+	memset(physical_to_logical_pkg,
+	       0xff,
+	       sizeof(*physical_to_logical_pkg) * max_physical_pkg_id);
 	size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
 	physical_package_map = kzalloc(size, GFP_KERNEL);
 
-- 
2.9.3

[PATCH 2/4] x86/smpboot: Return directly after a failed kmalloc_array()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 5 Sep 2016 08:48:32 +0200

Return directly after a memory allocation failed at the beginning.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 arch/x86/kernel/smpboot.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 36cf27e..2ce06ef 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -352,6 +352,8 @@ static void __init smp_init_package_map(void)
 	physical_to_logical_pkg = kmalloc_array(max_physical_pkg_id,
 						sizeof(*physical_to_logical_pkg),
 						GFP_KERNEL);
+	if (!physical_to_logical_pkg)
+		return;
 	memset(physical_to_logical_pkg,
 	       0xff,
 	       sizeof(*physical_to_logical_pkg) * max_physical_pkg_id);
-- 
2.9.3

[PATCH 3/4] x86/smpboot: Replace one kzalloc() call by kcalloc()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 5 Sep 2016 09:29:40 +0200

* The script "checkpatch.pl" can point information out like the following.

  WARNING: Prefer kcalloc over kzalloc with multiply

  Thus fix the affected source code place.

* Replace the specification of a data type by a pointer dereference
  to make the corresponding size determination a bit safer according to
  the Linux coding style convention.

* Delete the local variable "size" which became unnecessary with
  this refactoring.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 arch/x86/kernel/smpboot.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2ce06ef..e3fdc44 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -311,7 +311,6 @@ EXPORT_SYMBOL(topology_phys_to_logical_pkg);
 static void __init smp_init_package_map(void)
 {
 	unsigned int ncpus, cpu;
-	size_t size;
 
 	/*
 	 * Today neither Intel nor AMD support heterogenous systems. That
@@ -357,8 +356,9 @@ static void __init smp_init_package_map(void)
 	memset(physical_to_logical_pkg,
 	       0xff,
 	       sizeof(*physical_to_logical_pkg) * max_physical_pkg_id);
-	size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
-	physical_package_map = kzalloc(size, GFP_KERNEL);
+	physical_package_map = kcalloc(BITS_TO_LONGS(max_physical_pkg_id),
+				       sizeof(*physical_package_map),
+				       GFP_KERNEL);
 
 	for_each_present_cpu(cpu) {
 		unsigned int apicid = apic->cpu_present_to_apicid(cpu);
-- 
2.9.3

[PATCH 4/4] x86/smpboot: Return directly after a failed kcalloc()

[SF Markus Elfring]

From: Markus Elfring <elfring@users.sourceforge.net>
Date: Mon, 5 Sep 2016 09:39:05 +0200

Return directly after a memory allocation failed in this function.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 arch/x86/kernel/smpboot.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index e3fdc44..a30f625 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -359,6 +359,10 @@ static void __init smp_init_package_map(void)
 	physical_package_map = kcalloc(BITS_TO_LONGS(max_physical_pkg_id),
 				       sizeof(*physical_package_map),
 				       GFP_KERNEL);
+	if (!physical_package_map) {
+		kfree(physical_to_logical_pkg);
+		return;
+	}
 
 	for_each_present_cpu(cpu) {
 		unsigned int apicid = apic->cpu_present_to_apicid(cpu);
-- 
2.9.3

Re: [PATCH 1/4] x86/smpboot: Use kmalloc_array() in smp_init_package_map()

[Thomas Gleixner]

On Mon, 5 Sep 2016, SF Markus Elfring wrote:

> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Mon, 5 Sep 2016 08:30:20 +0200
> 
> * A multiplication for the size determination of a memory allocation
>   indicated that an array data structure should be processed.
>   Thus use the corresponding function "kmalloc_array".
> 
>   This issue was detected by using the Coccinelle software.
> 
> * Replace the specification of a data type by a pointer dereference
>   to make the corresponding size determination a bit safer according to
>   the Linux coding style convention.
> 
> * Move a calculation for one function call.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  arch/x86/kernel/smpboot.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 3878725..36cf27e 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -349,9 +349,12 @@ static void __init smp_init_package_map(void)
>  	 * package can be smaller than the actual used apic ids.
>  	 */
>  	max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
> -	size = max_physical_pkg_id * sizeof(unsigned int);
> -	physical_to_logical_pkg = kmalloc(size, GFP_KERNEL);
> -	memset(physical_to_logical_pkg, 0xff, size);
> +	physical_to_logical_pkg = kmalloc_array(max_physical_pkg_id,
> +						sizeof(*physical_to_logical_pkg),
> +						GFP_KERNEL);
> +	memset(physical_to_logical_pkg,
> +	       0xff,
> +	       sizeof(*physical_to_logical_pkg) * max_physical_pkg_id);


Why are you replacing well readable code by this line breaked crap?

Stop acting like a shell script or we might replace you by one.

Thanks,

	tglx

Re: [PATCH 3/4] x86/smpboot: Replace one kzalloc() call by kcalloc()

[Paolo Bonzini]

On 05/09/2016 10:12, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Mon, 5 Sep 2016 09:29:40 +0200
> 
> * The script "checkpatch.pl" can point information out like the following.
> 
>   WARNING: Prefer kcalloc over kzalloc with multiply
> 
>   Thus fix the affected source code place.
> 
> * Replace the specification of a data type by a pointer dereference
>   to make the corresponding size determination a bit safer according to
>   the Linux coding style convention.
> 
> * Delete the local variable "size" which became unnecessary with
>   this refactoring.
> 
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> ---
>  arch/x86/kernel/smpboot.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 2ce06ef..e3fdc44 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -311,7 +311,6 @@ EXPORT_SYMBOL(topology_phys_to_logical_pkg);
>  static void __init smp_init_package_map(void)
>  {
>  	unsigned int ncpus, cpu;
> -	size_t size;
>  
>  	/*
>  	 * Today neither Intel nor AMD support heterogenous systems. That
> @@ -357,8 +356,9 @@ static void __init smp_init_package_map(void)
>  	memset(physical_to_logical_pkg,
>  	       0xff,
>  	       sizeof(*physical_to_logical_pkg) * max_physical_pkg_id);
> -	size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
> -	physical_package_map = kzalloc(size, GFP_KERNEL);
> +	physical_package_map = kcalloc(BITS_TO_LONGS(max_physical_pkg_id),
> +				       sizeof(*physical_package_map),
> +				       GFP_KERNEL);

This is bitmap_alloc.

Paolo

>  	for_each_present_cpu(cpu) {
>  		unsigned int apicid = apic->cpu_present_to_apicid(cpu);
> 

Re: [PATCH 3/4] x86/smpboot: Replace one kzalloc() call by kcalloc()

[Paolo Bonzini]

On 05/09/2016 11:26, Paolo Bonzini wrote:
> 
> 
> On 05/09/2016 10:12, SF Markus Elfring wrote:
>> From: Markus Elfring <elfring@users.sourceforge.net>
>> Date: Mon, 5 Sep 2016 09:29:40 +0200
>>
>> * The script "checkpatch.pl" can point information out like the following.
>>
>>   WARNING: Prefer kcalloc over kzalloc with multiply
>>
>>   Thus fix the affected source code place.
>>
>> * Replace the specification of a data type by a pointer dereference
>>   to make the corresponding size determination a bit safer according to
>>   the Linux coding style convention.
>>
>> * Delete the local variable "size" which became unnecessary with
>>   this refactoring.
>>
>> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
>> ---
>>  arch/x86/kernel/smpboot.c | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
>> index 2ce06ef..e3fdc44 100644
>> --- a/arch/x86/kernel/smpboot.c
>> +++ b/arch/x86/kernel/smpboot.c
>> @@ -311,7 +311,6 @@ EXPORT_SYMBOL(topology_phys_to_logical_pkg);
>>  static void __init smp_init_package_map(void)
>>  {
>>  	unsigned int ncpus, cpu;
>> -	size_t size;
>>  
>>  	/*
>>  	 * Today neither Intel nor AMD support heterogenous systems. That
>> @@ -357,8 +356,9 @@ static void __init smp_init_package_map(void)
>>  	memset(physical_to_logical_pkg,
>>  	       0xff,
>>  	       sizeof(*physical_to_logical_pkg) * max_physical_pkg_id);
>> -	size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
>> -	physical_package_map = kzalloc(size, GFP_KERNEL);
>> +	physical_package_map = kcalloc(BITS_TO_LONGS(max_physical_pkg_id),
>> +				       sizeof(*physical_package_map),
>> +				       GFP_KERNEL);
> 
> This is bitmap_alloc.

Doh, bitmap_alloc is only in tools/include/linux/bitmap.h, but perhaps
it makes sense to add it to include/linux/bitmap.h or
include/linux/slab.h too...

Paolo