ACK: [SRU][Xenial][PATCH 1/1] s390/qeth: use vzalloc for QUERY OAT buffer

[Kleber Souza]

On 09/20/18 11:42, Joseph Salisbury wrote:
> From: Wenjia Zhang <wenjia at 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 at linux.ibm.com>
> Reviewed-by: Julian Wiedmann <jwi at linux.ibm.com>
> Signed-off-by: Julian Wiedmann <jwi at linux.ibm.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
> (backported from commit aec45e857c5538664edb76a60dd452e3265f37d1)
> Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>

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

> ---
>  drivers/s390/net/qeth_core_main.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
> index 40284b4..f0a34a2 100644
> --- a/drivers/s390/net/qeth_core_main.c
> +++ b/drivers/s390/net/qeth_core_main.c
> @@ -19,6 +19,8 @@
>  #include <linux/mii.h>
>  #include <linux/kthread.h>
>  #include <linux/slab.h>
> +#include <linux/vmalloc.h>
> +
>  #include <net/iucv/af_iucv.h>
>  #include <net/dsfield.h>
>  
> @@ -4705,7 +4707,7 @@ 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;
> @@ -4746,7 +4748,7 @@ 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;
>  }
>