[2/2] qlcnic: using too much stack

qlcnic_pci_info structs are 128 bytes so an array of 8 uses 1024 bytes.
That's a lot if you run with 4K stacks.  I allocated them with kcalloc()
instead.

Signed-off-by: Dan Carpenter <error27@gmail.com>

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On Aug 9, 2010, at 4:07 PM, Dan Carpenter wrote:

> qlcnic_pci_info structs are 128 bytes so an array of 8 uses 1024 bytes.
> That's a lot if you run with 4K stacks.  I allocated them with kcalloc()
> instead.
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> 
> diff --git a/drivers/net/qlcnic/qlcnic_main.c b/drivers/net/qlcnic/qlcnic_main.c
> index 7f27e2a..da84229 100644
> --- a/drivers/net/qlcnic/qlcnic_main.c
> +++ b/drivers/net/qlcnic/qlcnic_main.c
> @@ -473,14 +473,20 @@ qlcnic_cleanup_pci_map(struct qlcnic_adapter *adapter)
> static int
> qlcnic_init_pci_info(struct qlcnic_adapter *adapter)
> {
> -	struct qlcnic_pci_info pci_info[QLCNIC_MAX_PCI_FUNC];
> +	struct qlcnic_pci_info *pci_info;
> 	int i, ret = 0, err;
> 	u8 pfn;
> 
> +	pci_info = kcalloc(QLCNIC_MAX_PCI_FUNC, sizeof(*pci_info), GFP_KERNEL);
> +	if (!pci_info)
> +		return -ENOMEM;
> +
> 	adapter->npars = kzalloc(sizeof(struct qlcnic_npar_info) *
> 				QLCNIC_MAX_PCI_FUNC, GFP_KERNEL);
> -	if (!adapter->npars)
> -		return -ENOMEM;
> +	if (!adapter->npars) {
> +		err = -ENOMEM;
> +		goto err_pci_info;
> +	}
> 
> 	adapter->eswitch = kzalloc(sizeof(struct qlcnic_eswitch) *
> 				QLCNIC_NIU_MAX_XG_PORTS, GFP_KERNEL);
> @@ -508,6 +514,7 @@ qlcnic_init_pci_info(struct qlcnic_adapter *adapter)
> 	for (i = 0; i < QLCNIC_NIU_MAX_XG_PORTS; i++)
> 		adapter->eswitch[i].flags |= QLCNIC_SWITCH_ENABLE;
> 
> +	kfree(pci_info);
> 	return 0;
> 
> err_eswitch:
> @@ -516,6 +523,8 @@ err_eswitch:
> err_npars:
> 	kfree(adapter->npars);
> 	adapter->eswitch = NULL;
> +err_pci_info:
> +	kfree(pci_info);
> 
> 	return ret;
> }
> @@ -3362,15 +3371,21 @@ qlcnic_sysfs_read_pci_config(struct file *file, struct kobject *kobj,
> 	struct device *dev = container_of(kobj, struct device, kobj);
> 	struct qlcnic_adapter *adapter = dev_get_drvdata(dev);
> 	struct qlcnic_pci_func_cfg pci_cfg[QLCNIC_MAX_PCI_FUNC];
> -	struct qlcnic_pci_info	pci_info[QLCNIC_MAX_PCI_FUNC];
> +	struct qlcnic_pci_info *pci_info;
> 	int i, ret;
> 
> 	if (size != sizeof(pci_cfg))
> 		return QL_STATUS_INVALID_PARAM;
> 
> +	pci_info = kcalloc(QLCNIC_MAX_PCI_FUNC, sizeof(*pci_info), GFP_KERNEL);
> +	if (!pci_info)
> +		return -ENOMEM;
> +
> 	ret = qlcnic_get_pci_info(adapter, pci_info);
> -	if (ret)
> +	if (ret) {
> +		kfree(pci_info);
> 		return ret;
> +	}
> 
> 	for (i = 0; i < QLCNIC_MAX_PCI_FUNC ; i++) {
> 		pci_cfg[i].pci_func = pci_info[i].id;
> @@ -3381,8 +3396,8 @@ qlcnic_sysfs_read_pci_config(struct file *file, struct kobject *kobj,
> 		memcpy(&pci_cfg[i].def_mac_addr, &pci_info[i].mac, ETH_ALEN);
> 	}
> 	memcpy(buf, &pci_cfg, size);
> +	kfree(pci_info);
> 	return size;
> -
> }
> static struct bin_attribute bin_attr_npar_config = {
> 	.attr = {.name = "npar_config", .mode = (S_IRUGO | S_IWUSR)},

It looks fine except that I'd use kzalloc instead of kcalloc above.

thanks,
-Anirban--
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On Mon, Aug 09, 2010 at 09:46:32AM -0700, Anirban Chakraborty wrote:
> 
> It looks fine except that I'd use kzalloc instead of kcalloc above.
> 

It's no problem to do that, and I'm already respinning the patches but 
I'm confused.  It looks like pci_info gets initialized correctly.  What
am I missing?

regards,
dan carpenter

> thanks,
> -Anirban
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On Aug 10, 2010, at 12:12 AM, Dan Carpenter wrote:

> On Mon, Aug 09, 2010 at 09:46:32AM -0700, Anirban Chakraborty wrote:
>> 
>> It looks fine except that I'd use kzalloc instead of kcalloc above.
>> 
> 
> It's no problem to do that, and I'm already respinning the patches but 
> I'm confused.  It looks like pci_info gets initialized correctly.  What
> am I missing?

Your patch is fine except that the preferred way is to use kzalloc over kaclloc. kzalloc does not need that extra
argument that you are passing to kcalloc.

-Anirban--
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On Mon, 2010-08-09 at 18:43 -0700, Anirban Chakraborty wrote:
> Your patch is fine except that the preferred way is to use kzalloc over kaclloc. kzalloc does not need that extra
> argument that you are passing to kcalloc.

You probably meant to write "my preferred way"
as the kcalloc to "kzalloc with a multiply"
ratio is pretty high.

It's actually about 2.5 to 1 in favor of kcalloc.

$ grep -rw --include=*.[ch] kcalloc * | wc -l
419

$ grep -rP --include=*.[ch] "\bkzalloc\s*\(\s*\w+\s*\*\s*\w+" * | \
  grep -vP "\bkzalloc\s*\(\s*sizeof\s+\*\s*\w+\s*," | wc -l
164

(the grep -vP avoids kzalloc(sizeof *p, GFP_foo)

Actually, there might be a reason to use kzalloc
in that location to match the other similar use
a few lines away, but I'd prefer that the other
use be converted to kcalloc.

cheers, Joe

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On Aug 10, 2010, at 7:33 AM, Joe Perches wrote:

> On Mon, 2010-08-09 at 18:43 -0700, Anirban Chakraborty wrote:
>> Your patch is fine except that the preferred way is to use kzalloc over kaclloc. kzalloc does not need that extra
>> argument that you are passing to kcalloc.
> 
> You probably meant to write "my preferred way"
> as the kcalloc to "kzalloc with a multiply"
> ratio is pretty high.
> 
> It's actually about 2.5 to 1 in favor of kcalloc.
> 
> $ grep -rw --include=*.[ch] kcalloc * | wc -l
> 419
> 
> $ grep -rP --include=*.[ch] "\bkzalloc\s*\(\s*\w+\s*\*\s*\w+" * | \
>  grep -vP "\bkzalloc\s*\(\s*sizeof\s+\*\s*\w+\s*," | wc -l
> 164
> 
> (the grep -vP avoids kzalloc(sizeof *p, GFP_foo)
> 
> Actually, there might be a reason to use kzalloc
> in that location to match the other similar use
> a few lines away, but I'd prefer that the other
> use be converted to kcalloc.

I was suggesting based on the following:
http://lwn.net/Articles/147014/

thanks,
Anirban


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On Mon, 2010-08-09 at 20:31 -0700, Anirban Chakraborty wrote:
> On Aug 10, 2010, at 7:33 AM, Joe Perches wrote:
> > On Mon, 2010-08-09 at 18:43 -0700, Anirban Chakraborty wrote:
> >> Your patch is fine except that the preferred way is to use kzalloc over kaclloc. kzalloc does not need that extra
> >> argument that you are passing to kcalloc.
> > You probably meant to write "my preferred way"
> > as the kcalloc to "kzalloc with a multiply"
> > ratio is pretty high.
> I was suggesting based on the following:
> http://lwn.net/Articles/147014/

Note that article suggests kzalloc for allocating
a single zeroed object.

kcalloc is used for multiple zeroed objects and
protects against oversized allocations.


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From: Joe Perches <joe@perches.com>
Date: Mon, 09 Aug 2010 20:39:06 -0700

> On Mon, 2010-08-09 at 20:31 -0700, Anirban Chakraborty wrote:
>> On Aug 10, 2010, at 7:33 AM, Joe Perches wrote:
>> > On Mon, 2010-08-09 at 18:43 -0700, Anirban Chakraborty wrote:
>> >> Your patch is fine except that the preferred way is to use kzalloc over kaclloc. kzalloc does not need that extra
>> >> argument that you are passing to kcalloc.
>> > You probably meant to write "my preferred way"
>> > as the kcalloc to "kzalloc with a multiply"
>> > ratio is pretty high.
>> I was suggesting based on the following:
>> http://lwn.net/Articles/147014/
> 
> Note that article suggests kzalloc for allocating
> a single zeroed object.
> 
> kcalloc is used for multiple zeroed objects and
> protects against oversized allocations.

Agreed, kcalloc should be used here.
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