[SRU,Bionic,Cosmic,1/1] s390/qeth: use vzalloc for QUERY OAT buffer

From: Wenjia Zhang <wenjia@linux.ibm.com>

BugLink: https://bugs.launchpad.net/bugs/1793086

qeth_query_oat_command() currently allocates the kernel buffer for
the SIOC_QETH_QUERY_OAT ioctl with kzalloc. So on systems with
fragmented memory, large allocations may fail (eg. the qethqoat tool by
default uses 132KB).

Solve this issue by using vzalloc, backing the allocation with
non-contiguous memory.

Signed-off-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit aec45e857c5538664edb76a60dd452e3265f37d1)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
---
 drivers/s390/net/qeth_core_main.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

On 20.09.2018 11:31, Joseph Salisbury wrote:
> From: Wenjia Zhang <wenjia@linux.ibm.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1793086
> 
> qeth_query_oat_command() currently allocates the kernel buffer for
> the SIOC_QETH_QUERY_OAT ioctl with kzalloc. So on systems with
> fragmented memory, large allocations may fail (eg. the qethqoat tool by
> default uses 132KB).
> 
> Solve this issue by using vzalloc, backing the allocation with
> non-contiguous memory.
> 
> Signed-off-by: Wenjia Zhang <wenjia@linux.ibm.com>
> Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> (cherry picked from commit aec45e857c5538664edb76a60dd452e3265f37d1)
> Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
> ---
>  drivers/s390/net/qeth_core_main.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
> index d01ac29..02b7352 100644
> --- a/drivers/s390/net/qeth_core_main.c
> +++ b/drivers/s390/net/qeth_core_main.c
> @@ -25,6 +25,7 @@
>  #include <linux/netdevice.h>
>  #include <linux/netdev_features.h>
>  #include <linux/skbuff.h>
> +#include <linux/vmalloc.h>
>  
>  #include <net/iucv/af_iucv.h>
>  #include <net/dsfield.h>
> @@ -4737,7 +4738,7 @@ static int qeth_query_oat_command(struct qeth_card *card, char __user *udata)
>  
>  	priv.buffer_len = oat_data.buffer_len;
>  	priv.response_len = 0;
> -	priv.buffer =  kzalloc(oat_data.buffer_len, GFP_KERNEL);
> +	priv.buffer = vzalloc(oat_data.buffer_len);
>  	if (!priv.buffer) {
>  		rc = -ENOMEM;
>  		goto out;
> @@ -4778,7 +4779,7 @@ static int qeth_query_oat_command(struct qeth_card *card, char __user *udata)
>  			rc = -EFAULT;
>  
>  out_free:
> -	kfree(priv.buffer);
> +	vfree(priv.buffer);
>  out:
>  	return rc;
>  }
>

On 09/20/18 11:31, Joseph Salisbury wrote:
> From: Wenjia Zhang <wenjia@linux.ibm.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1793086
> 
> qeth_query_oat_command() currently allocates the kernel buffer for
> the SIOC_QETH_QUERY_OAT ioctl with kzalloc. So on systems with
> fragmented memory, large allocations may fail (eg. the qethqoat tool by
> default uses 132KB).
> 
> Solve this issue by using vzalloc, backing the allocation with
> non-contiguous memory.
> 
> Signed-off-by: Wenjia Zhang <wenjia@linux.ibm.com>
> Reviewed-by: Julian Wiedmann <jwi@linux.ibm.com>
> Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> (cherry picked from commit aec45e857c5538664edb76a60dd452e3265f37d1)
> Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>

Acked-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

> ---
>  drivers/s390/net/qeth_core_main.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
> index d01ac29..02b7352 100644
> --- a/drivers/s390/net/qeth_core_main.c
> +++ b/drivers/s390/net/qeth_core_main.c
> @@ -25,6 +25,7 @@
>  #include <linux/netdevice.h>
>  #include <linux/netdev_features.h>
>  #include <linux/skbuff.h>
> +#include <linux/vmalloc.h>
>  
>  #include <net/iucv/af_iucv.h>
>  #include <net/dsfield.h>
> @@ -4737,7 +4738,7 @@ static int qeth_query_oat_command(struct qeth_card *card, char __user *udata)
>  
>  	priv.buffer_len = oat_data.buffer_len;
>  	priv.response_len = 0;
> -	priv.buffer =  kzalloc(oat_data.buffer_len, GFP_KERNEL);
> +	priv.buffer = vzalloc(oat_data.buffer_len);
>  	if (!priv.buffer) {
>  		rc = -ENOMEM;
>  		goto out;
> @@ -4778,7 +4779,7 @@ static int qeth_query_oat_command(struct qeth_card *card, char __user *udata)
>  			rc = -EFAULT;
>  
>  out_free:
> -	kfree(priv.buffer);
> +	vfree(priv.buffer);
>  out:
>  	return rc;
>  }
>