linux-kernel - Re: [PATCH] ath6kl: Use vmalloc to allocate ar->fw for api1 method

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Message-ID: <CAFqt6zZfmue6XVVno2Ho8UfEwz1Z3YxFzbcZ9ZMOn5Fe_zJLmQ@mail.gmail.com>
Date:	Tue, 22 Dec 2015 14:35:20 +0530
From:	Souptick Joarder <jrdr.linux@...il.com>
To:	Brent Taylor <motobud@...il.com>
Cc:	Kalle Valo <kvalo@....qualcomm.com>,
	linux-wireless <linux-wireless@...r.kernel.org>,
	netdev@...r.kernel.org,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	ath6kl@...ts.infradead.org
Subject: Re: [PATCH] ath6kl: Use vmalloc to allocate ar->fw for api1 method

Hi Brent,

On Tue, Dec 22, 2015 at 3:23 AM, Brent Taylor <motobud@...il.com> wrote:
> On Mon, Dec 21, 2015 at 1:23 PM, Souptick Joarder <jrdr.linux@...il.com> wrote:
>> Hi Brent,
>>
>> On Tue, Dec 1, 2015 at 11:11 AM, Brent Taylor <motobud@...il.com> wrote:
>>> Since commit 8437754c83351d6213c1a47ff029c1126d6042a7, ar->fw is expected to be pointing to memory allocated by vmalloc.  If the api1 method (via ath6kl_fetch_fw_api1) is used to allocate memory for ar->fw, then kmemdup is used.  This patch checks if the firmware being loaded is the 'fw' image, then use vmalloc, otherwise use kmalloc.
>>>
>>> Signed-off-by: Brent Taylor <motobud@...il.com>
>>> ---
>>>  drivers/net/wireless/ath/ath6kl/init.c | 7 ++++++-
>>>  1 file changed, 6 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/wireless/ath/ath6kl/init.c b/drivers/net/wireless/ath/ath6kl/init.c
>>> index 6ae0734..4f2b124d 100644
>>> --- a/drivers/net/wireless/ath/ath6kl/init.c
>>> +++ b/drivers/net/wireless/ath/ath6kl/init.c
>>> @@ -673,10 +673,15 @@ static int ath6kl_get_fw(struct ath6kl *ar, const char *filename,
>>>                 return ret;
>>>
>>>         *fw_len = fw_entry->size;
>>> -       *fw = kmemdup(fw_entry->data, fw_entry->size, GFP_KERNEL);
>>> +   if (&ar->fw == fw)
>>> +               *fw = vmalloc(fw_entry->size);
>>> +   else
>>> +               *fw = kmalloc(fw_entry->size, GFP_KERNEL)
>>
>>           Why vmalloc and kmalloc both are required? can't use either
>> vmalloc or kmalloc?
>
> My original problem was that kmemdup (which uses kmalloc) could not
> allocate enough memory

If kmemdump ( which uses kmalloc) could not allocate memory then
using kmalloc again can lead to same problem.
I guess it will be correct to use
            *fw = vmalloc(fw_entry->size);
Correct me if i am wrong.

> to hold the firmware that is placed into "ar->fw".  In the function
> ath6kl_core_cleanup (in core.c),
> the "ar->fw" pointer is the only one that uses vfree which was changed in commit
> 8437754c83351d6213c1a47ff029c1126d6042a7.
>
> I was trying to change as little as possible and I wasn't sure if
> there was a reason that any of the
> other firmware items needed to be allocated with kmalloc or if they
> could be changed to use vmalloc.

-Souptick
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