Re: [Intel-wired-lan] [PATCH 2/4] ice: use kzalloc() to allocate staging buffer for reading from GNSS

[Przemek Kitszel <przemyslaw.kitszel@intel.com>]

On 7/2/26 4:40 PM, Mike Rapoport wrote:
> On Thu, Jul 02, 2026 at 03:49:36PM +0200, Przemek Kitszel wrote:
>> On 7/1/26 15:57, Mike Rapoport (Microsoft) wrote:
>>> ice_gnss_read() uses get_zeroed_page() to  allocate a staging buffer for
>>> reading GNSS module data via I2C bus.
>>>
>>> This buffer can be allocated with kmalloc() as there's nothing special
>>> about it to go directly to the page allocator.
>>>
>>> kmalloc() provides a better API that does not require ugly casts and
>>> kfree() does not need to know the size of the freed object.
>>>
>>> Performance difference between kmalloc() and __get_free_pages() is not
>>> measurable as both allocators take an object/page from a per-CPU list for
>>> fast path allocations.
>>>
>>> For the slow path the performance is anyway determined by the amount of
>>> reclaim involved rather than by what allocator is used.
>>>
>>> Replace use of get_zeroed_page() with kzalloc() and free_page() with
>>> kfree().
>>>
>>> Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com
>>> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
>>> ---
>>>    drivers/net/ethernet/intel/ice/ice_gnss.c | 5 +++--
>>>    1 file changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/intel/ice/ice_gnss.c b/drivers/net/ethernet/intel/ice/ice_gnss.c
>>> index 8fd954f1ebd6..7d21c3417b0b 100644
>>> --- a/drivers/net/ethernet/intel/ice/ice_gnss.c
>>> +++ b/drivers/net/ethernet/intel/ice/ice_gnss.c
>>> @@ -2,6 +2,7 @@
>>>    /* Copyright (C) 2021-2022, Intel Corporation. */
>>>    #include "ice.h"
>>> +#include <linux/slab.h>
>>>    #include "ice_lib.h"
>>>    /**
>>> @@ -124,7 +125,7 @@ static void ice_gnss_read(struct kthread_work *work)
>>>    	data_len = min_t(typeof(data_len), data_len, PAGE_SIZE);
>>> -	buf = (char *)get_zeroed_page(GFP_KERNEL);
>>> +	buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
>>
>> nit:
>> from the code it is clear that we read at most a page, and @data_len
>> stores the actual amount needed
>>
>> comment:
>> I don't know why we limit to a page, it's outside of the scope of this
>> series, but likely you have removed the limit (which will go into the
>> loop - single AQ call is likely limited by a PAGE too).
> 
> Not sure I follow how the limit changed. buf remains PAGE_SIZE regardless
> of allocation API.

data_len passed by the caller could be bigger than PAGE_SIZE, we cap it
to PAGE_SIZE, likely due to the old allocation method
but I don't insist on any change to this patch (esp. given all other are
fine)

>   
>> Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> 
> Thanks!
> 

We are fine to merge it directly via netdev.