Re: [PATCH iwl-next] i40e: Use correct buffer size

[Kunwu Chan]

Thanks you again for your reply.
I learned. I know how to use it, thanks, I'll look at the existing code 
and add logs to see how it works.

Thanks again.


On 2023/11/21 19:15, Alexander Lobakin wrote:
> From: Kunwu Chan <chentao@xxxxxxxxxx>
> Date: Tue, 21 Nov 2023 10:12:17 +0800
>
> > Thanks for your reply. I understand what you mean, i.e. the caller of
> > 'kasprintf' is responsible for calling 'kfree' to free up memory.
> >
> > My concern is that in many scenarios, the requested memory will be
> > released after a period of use.
> >
> > Has anyone else forgotten to free up the requested memory when using
> > 'kasprintf'? e.g. 'dam_heap_init' calls 'dma_heap_devnode' to allocate
> > memory:
> > dam_heap_init
> >      -> dma_heap_devnode
> >            -> kasprintf
> >              ->kvasprintf
> >                   ->kmalloc_node_track_caller
> >                    -> __kmalloc_node_track_caller
> >                        -> __do_kmalloc_node
> >                            -> kasan_kmalloc
> >
> >
> > There is no function like 'dam_heap_exit' to free the memmory allocated
> > by dma_heap_devnode.
> >
> > Another case is 'cpuid_devnode'. Will this cause a memory leak, and is
> > there a better way to avoid the memory leak in this case?
> >
> > Or is there a uniform place in the memory management module to free up
> > this memory?
>
> If the lifetime of the allocated buffer equals to the lifetime of the
> kernel, i.e. it's allocated once at kernel init and then used throughout
> the whole uptime, there's no need to free this piece.
> Temporary buffers or buffers allocated from a driver are a different
> story, their lifetime is shorter, which means you always need to
> manually free each of them on exit.
>
> > Thanks,
> > Kunwu
> Thanks,
> Olek