Re: [PATCH 21/24] usb: host: xhci: Move array of structs from the stack onto the heap

Mathias Nyman
2021-05-27T11:34:32Z

On 26.5.2021 18.28, Lee Jones wrote:
> On Wed, 26 May 2021, Sergei Shtylyov wrote:
>
>> On 5/26/21 5:44 PM, Lee Jones wrote:
>>
>> [...]
>>>>> Fixes the following W=1 kernel build warning(s):
>>>>>
>>>>> drivers/usb/host/xhci.c: In function ‘xhci_reserve_bandwidth’:
>>>>> drivers/usb/host/xhci.c:2859:1: warning: the frame size of 1032 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>>>>>
>>>>> Cc: Mathias Nyman <mathias.nyman@intel.com>
>>>>> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>>>>> Cc: linux-usb@vger.kernel.org
>>>>> Signed-off-by: Lee Jones <lee.jones@linaro.org>
>>>>> ---
>>>>> drivers/usb/host/xhci.c | 8 +++++++-
>>>>> 1 file changed, 7 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
>>>>> index ac2a7d4288883..40ce4b4eb12ad 100644
>>>>> --- a/drivers/usb/host/xhci.c
>>>>> +++ b/drivers/usb/host/xhci.c
>>>> [...]
>>>>> @@ -2788,6 +2788,10 @@ static int xhci_reserve_bandwidth(struct xhci_hcd *xhci,
>>>>> return -ENOMEM;
>>>>> }
>>>>>
>>>>> + ep_bw_info = kzalloc(sizeof(*ep_bw_info) * 31, GFP_KERNEL);

GFP_KERNEL might not be suitable for all cases.

xhci_reserve_bandwidth() is called from xhci_configure_endpoint(), which again
is called from a lot of places.
For example from xhci_update_hub_device() which can be called with GFP_NOIO mem_flags.

-Mathias