[PATCH 17/30] pci: Use kmemdup rather than duplicating its implementation

[PATCH 17/30] pci: Use kmemdup rather than duplicating its implementation

[Fuqian Huang]

kmemdup is introduced to duplicate a region of memory in a neat way.
Rather than kmalloc/kzalloc + memset, which the programmer needs to
write the size twice (sometimes lead to mistakes), kmemdup improves
readability, leads to smaller code and also reduce the chances of mistakes.
Suggestion to use kmemdup rather than using kmalloc/kzalloc + memset.

Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
---
 drivers/pci/hotplug/ibmphp_core.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c
index 17124254d897..0e340e105c3b 100644
--- a/drivers/pci/hotplug/ibmphp_core.c
+++ b/drivers/pci/hotplug/ibmphp_core.c
@@ -1261,19 +1261,18 @@ static int __init ibmphp_init(void)
 
 	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
 
-	ibmphp_pci_bus = kmalloc(sizeof(*ibmphp_pci_bus), GFP_KERNEL);
-	if (!ibmphp_pci_bus) {
-		rc = -ENOMEM;
-		goto exit;
-	}
-
 	bus = pci_find_bus(0, 0);
 	if (!bus) {
 		err("Can't find the root pci bus, can not continue\n");
 		rc = -ENODEV;
 		goto error;
 	}
-	memcpy(ibmphp_pci_bus, bus, sizeof(*ibmphp_pci_bus));
+
+	ibmphp_pci_bus = kmemdup(bus, sizeof(*ibmphp_pci_bus), GFP_KERNEL);
+	if (!ibmphp_pci_bus) {
+		rc = -ENOMEM;
+		goto exit;
+	}
 
 	ibmphp_debug = debug;
 
-- 
2.11.0

RE: [PATCH 17/30] pci: Use kmemdup rather than duplicating its implementation

[David Laight]

From: Fuqian Huang
> Sent: 03 July 2019 14:16
> 
> kmemdup is introduced to duplicate a region of memory in a neat way.
> Rather than kmalloc/kzalloc + memset, which the programmer needs to
> write the size twice (sometimes lead to mistakes), kmemdup improves
> readability, leads to smaller code and also reduce the chances of mistakes.
> Suggestion to use kmemdup rather than using kmalloc/kzalloc + memset.
> 
> Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
> ---
>  drivers/pci/hotplug/ibmphp_core.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/pci/hotplug/ibmphp_core.c b/drivers/pci/hotplug/ibmphp_core.c
> index 17124254d897..0e340e105c3b 100644
> --- a/drivers/pci/hotplug/ibmphp_core.c
> +++ b/drivers/pci/hotplug/ibmphp_core.c
> @@ -1261,19 +1261,18 @@ static int __init ibmphp_init(void)
> 
>  	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
> 
> -	ibmphp_pci_bus = kmalloc(sizeof(*ibmphp_pci_bus), GFP_KERNEL);
> -	if (!ibmphp_pci_bus) {
> -		rc = -ENOMEM;
> -		goto exit;
> -	}
> -
>  	bus = pci_find_bus(0, 0);
>  	if (!bus) {
>  		err("Can't find the root pci bus, can not continue\n");
>  		rc = -ENODEV;
>  		goto error;
>  	}
> -	memcpy(ibmphp_pci_bus, bus, sizeof(*ibmphp_pci_bus));
> +
> +	ibmphp_pci_bus = kmemdup(bus, sizeof(*ibmphp_pci_bus), GFP_KERNEL);
> +	if (!ibmphp_pci_bus) {
> +		rc = -ENOMEM;
> +		goto exit;
> +	}

Not sure why I even looked as this...

But the error path if pci_find_bus() fails is now wrong.

	David

-
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