Re: [PATCH v1 3/5] misc: fastrpc: Fix initial memory allocation for Audio PD memory pool

[Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>]

On 5/19/2025 7:01 PM, Dmitry Baryshkov wrote:
> On Mon, May 19, 2025 at 04:23:28PM +0530, Ekansh Gupta wrote:
>>
>> On 5/19/2025 3:47 PM, Dmitry Baryshkov wrote:
>>> On Tue, May 13, 2025 at 09:58:23AM +0530, Ekansh Gupta wrote:
>>>> The initially allocated memory is not properly included in the pool,
>>>> leading to potential issues with memory management. Set the number
>>> What is 'properly'? Which issues?
>> inbuf.pageslen is getting updated to 1 in case buffer is allocated,
> Is it a flag or some page count?

This is page count, based on this count, DSP with add memory to audioPD
pool. If it is 0, the memory is not added.

>
>> which only
>> happens if (!fl->cctx->audio_init_mem).
> You are describing patch behaviour.
>
>> Till now pageslen is always 0 irrespective of whether the memory is allocated
>> or not due to which audio PD is never able to use this memory.
> and the is current behaviour. So this answers the first question.
> 'properly'. Now, the second quesiton. 'Which issues?'

The issues is actually memory leak as the initial memory is never
used by audio PD and it will immediately make a remote heap request
as no memory is added to the pool initially.

I'll capture this also in the commit text.

>
>> I'll update this to the commit in the next spin.
>>
>>>> of pages to one to ensure that the initially allocated memory is
>>>> correctly added to the Audio PD memory pool.
>>>>
>>>> Fixes: 0871561055e66 ("misc: fastrpc: Add support for audiopd")
>>>> Cc: stable@kernel.org
>>>> Signed-off-by: Ekansh Gupta <ekansh.gupta@oss.qualcomm.com>
>>>> ---
>>>>  drivers/misc/fastrpc.c | 7 ++++---
>>>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
>>>> index d4e38b5e5e6c..b629e24f00bc 100644
>>>> --- a/drivers/misc/fastrpc.c
>>>> +++ b/drivers/misc/fastrpc.c
>>>> @@ -1311,6 +1311,9 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
>>>>  		goto err;
>>>>  	}
>>>>  
>>>> +	inbuf.client_id = fl->client_id;
>>>> +	inbuf.namelen = init.namelen;
>>>> +	inbuf.pageslen = 0;
>>>>  	if (!fl->cctx->audio_init_mem) {
>>>>  		err = fastrpc_remote_heap_alloc(fl, fl->sctx->dev, init.memlen,
>>>>  						&buf);
>>>> @@ -1335,12 +1338,10 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
>>>>  			list_add_tail(&buf->node, &fl->cctx->rhmaps);
>>>>  			spin_unlock_irqrestore(&fl->cctx->lock, flags);
>>>>  			fl->cctx->audio_init_mem = true;
>>>> +			inbuf.pageslen = 1;
>>>>  		}
>>>>  	}
>>>>  
>>>> -	inbuf.client_id = fl->client_id;
>>>> -	inbuf.namelen = init.namelen;
>>>> -	inbuf.pageslen = 0;
>>>>  	fl->pd = USER_PD;
>>>>  
>>>>  	args[0].ptr = (u64)(uintptr_t)&inbuf;
>>>> -- 
>>>> 2.34.1
>>>>