Thanks Ekansh for this patch.
few comments below
On 31/08/2023 07:23, Ekansh Gupta wrote:
> The FDs for DMA handles to be freed is updated in fdlist by DSP over
So the dsp is updating the fd list after invoke?
> a remote call. This holds true even for remote calls with no
> arguments. To handle this, get_args and put_args are needed to
> be called for remote calls with no arguments also as fdlist
> is allocated in get_args and FDs updated in fdlist is freed
> in put_args.
>
> Signed-off-by: Ekansh Gupta <[email protected]>
> ---
> drivers/misc/fastrpc.c | 22 +++++++++-------------
> 1 file changed, 9 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 9666d28..e6df66e 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -1153,11 +1153,9 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl, u32 kernel,
> if (IS_ERR(ctx))
> return PTR_ERR(ctx);
>
> - if (ctx->nscalars) {
Why do we need to remove this check?
fastrpc_internal_invoke will have nscalars set before calling. and we
are not dealing with fdlist in fastrpc_get_args(), so am not sure what
this change is helping with.
> - err = fastrpc_get_args(kernel, ctx);
> - if (err)
> - goto bail;
> - }
> + err = fastrpc_get_args(kernel, ctx);
> + if (err)
> + goto bail;
>
> /* make sure that all CPU memory writes are seen by DSP */
> dma_wmb();
> @@ -1181,14 +1179,12 @@ static int fastrpc_internal_invoke(struct fastrpc_user *fl, u32 kernel,
> if (err)
> goto bail;
>
> - if (ctx->nscalars) {
> - /* make sure that all memory writes by DSP are seen by CPU */
> - dma_rmb();
> - /* populate all the output buffers with results */
> - err = fastrpc_put_args(ctx, kernel);
> - if (err)
> - goto bail;
> - }
> + /* make sure that all memory writes by DSP are seen by CPU */
> + dma_rmb();
> + /* populate all the output buffers with results */
A comment about fdlist here would be really useful
> + err = fastrpc_put_args(ctx, kernel);
> + if (err)
> + goto bail;
>
> bail:
> if (err != -ERESTARTSYS && err != -ETIMEDOUT) {
On 9/26/2023 3:57 PM, Srinivas Kandagatla wrote:
> Thanks Ekansh for this patch.
>
> few comments below
>
> On 31/08/2023 07:23, Ekansh Gupta wrote:
>> The FDs for DMA handles to be freed is updated in fdlist by DSP over
>
> So the dsp is updating the fd list after invoke?
>
Yes, correct. DSP updates this fd list when the buffer is no longer
needed by the user PD.
>
>> a remote call. This holds true even for remote calls with no
>> arguments. To handle this, get_args and put_args are needed to
>> be called for remote calls with no arguments also as fdlist
>> is allocated in get_args and FDs updated in fdlist is freed
>> in put_args.
>>
>> Signed-off-by: Ekansh Gupta <[email protected]>
>> ---
>> drivers/misc/fastrpc.c | 22 +++++++++-------------
>> 1 file changed, 9 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
>> index 9666d28..e6df66e 100644
>> --- a/drivers/misc/fastrpc.c
>> +++ b/drivers/misc/fastrpc.c
>> @@ -1153,11 +1153,9 @@ static int fastrpc_internal_invoke(struct
>> fastrpc_user *fl, u32 kernel,
>> if (IS_ERR(ctx))
>> return PTR_ERR(ctx);
>> - if (ctx->nscalars) {
>
> Why do we need to remove this check?
> fastrpc_internal_invoke will have nscalars set before calling. and we
> are not dealing with fdlist in fastrpc_get_args(), so am not sure what
> this change is helping with.
Memory for fdlist is allocated as part of fastrpc_get_args. The reason
to add this change is that fdlist can be updated by DSP over a call with
no remote arguments, for this call, there should be some fdlist
allocated so the DSP can update the list if needed. Same apply for
fastrpc_put_args also as when DSP updates fdlist for any remote call
with no arguments, the maps corresponding to the fdlist should be freed.
>
>
>> - err = fastrpc_get_args(kernel, ctx);
>> - if (err)
>> - goto bail;
>> - }
>> + err = fastrpc_get_args(kernel, ctx);
>> + if (err)
>> + goto bail;
>> /* make sure that all CPU memory writes are seen by DSP */
>> dma_wmb();
>> @@ -1181,14 +1179,12 @@ static int fastrpc_internal_invoke(struct
>> fastrpc_user *fl, u32 kernel,
>> if (err)
>> goto bail;
>> - if (ctx->nscalars) {
>> - /* make sure that all memory writes by DSP are seen by CPU */
>> - dma_rmb();
>> - /* populate all the output buffers with results */
>> - err = fastrpc_put_args(ctx, kernel);
>> - if (err)
>> - goto bail;
>> - }
>> + /* make sure that all memory writes by DSP are seen by CPU */
>> + dma_rmb();
>> + /* populate all the output buffers with results */
>
> A comment about fdlist here would be really useful
Sure, I will add a comment in the next patch. Do you suggest to add
comment here or inside fastrpc_put_args function:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/misc/fastrpc.c#n1092
>
>> + err = fastrpc_put_args(ctx, kernel);
>> + if (err)
>> + goto bail;
>> bail:
>> if (err != -ERESTARTSYS && err != -ETIMEDOUT) {