[PATCH v4 1/2] misc: fastrpc: Add support for multiple PD from one process

Ekansh Gupta quic_ekangupt at quicinc.com
Fri Nov 29 11:22:56 UTC 2024



On 11/22/2024 3:51 AM, Dmitry Baryshkov wrote:
> On Thu, Nov 21, 2024 at 02:17:12PM +0530, Ekansh Gupta wrote:
>> Memory intensive applications(which requires more tha 4GB) that wants
>> to offload tasks to DSP might have to split the tasks to multiple
>> user PD to make the resources available.
>>
>> For every call to DSP, fastrpc driver passes the process tgid which
>> works as an identifier for the DSP to enqueue the tasks to specific PD.
>> With current design, if any process opens device node more than once
>> and makes PD init request, same tgid will be passed to DSP which will
>> be considered a bad request and this will result in failure as the same
>> identifier cannot be used for multiple DSP PD.
>>
>> Assign and pass a client ID to DSP which would be assigned during device
>> open and will be dependent on the index of session allocated for the PD.
>> This will allow the same process to open the device more than once and
>> spawn multiple dynamic PD for ease of processing.
>>
>> Signed-off-by: Ekansh Gupta <quic_ekangupt at quicinc.com>
>> ---
>>  drivers/misc/fastrpc.c | 30 ++++++++++++++++--------------
>>  1 file changed, 16 insertions(+), 14 deletions(-)
>>
>> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
>> index 74181b8c386b..08f223c95c33 100644
>> --- a/drivers/misc/fastrpc.c
>> +++ b/drivers/misc/fastrpc.c
>> @@ -39,6 +39,7 @@
>>  #define FASTRPC_INIT_HANDLE	1
>>  #define FASTRPC_DSP_UTILITIES_HANDLE	2
>>  #define FASTRPC_CTXID_MASK (0xFF0)
>> +#define FASTRPC_CLIENTID_MASK GENMASK(4, 4)
> GENMASK(4,4) is just BIT(4), isn't it?
>
>>  #define INIT_FILELEN_MAX (2 * 1024 * 1024)
>>  #define INIT_FILE_NAMELEN_MAX (128)
>>  #define FASTRPC_DEVICE_NAME	"fastrpc"
>> @@ -299,7 +300,7 @@ struct fastrpc_user {
>>  	struct fastrpc_session_ctx *sctx;
>>  	struct fastrpc_buf *init_mem;
>>  
>> -	int tgid;
>> +	int client_id;
>>  	int pd;
>>  	bool is_secure_dev;
>>  	/* Lock for lists */
>> @@ -614,7 +615,7 @@ static struct fastrpc_invoke_ctx *fastrpc_context_alloc(
>>  	ctx->sc = sc;
>>  	ctx->retval = -1;
>>  	ctx->pid = current->pid;
>> -	ctx->tgid = user->tgid;
>> +	ctx->tgid = user->client_id;
>>  	ctx->cctx = cctx;
>>  	init_completion(&ctx->work);
>>  	INIT_WORK(&ctx->put_work, fastrpc_context_put_wq);
>> @@ -1115,7 +1116,7 @@ static int fastrpc_invoke_send(struct fastrpc_session_ctx *sctx,
>>  	int ret;
>>  
>>  	cctx = fl->cctx;
>> -	msg->pid = fl->tgid;
>> +	msg->pid = fl->client_id;
>>  	msg->tid = current->pid;
>>  
>>  	if (kernel)
>> @@ -1293,7 +1294,7 @@ static int fastrpc_init_create_static_process(struct fastrpc_user *fl,
>>  		}
>>  	}
>>  
>> -	inbuf.pgid = fl->tgid;
>> +	inbuf.pgid = fl->client_id;
>>  	inbuf.namelen = init.namelen;
>>  	inbuf.pageslen = 0;
>>  	fl->pd = USER_PD;
>> @@ -1395,7 +1396,7 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
>>  		goto err;
>>  	}
>>  
>> -	inbuf.pgid = fl->tgid;
>> +	inbuf.pgid = fl->client_id;
>>  	inbuf.namelen = strlen(current->comm) + 1;
>>  	inbuf.filelen = init.filelen;
>>  	inbuf.pageslen = 1;
>> @@ -1469,8 +1470,9 @@ static int fastrpc_init_create_process(struct fastrpc_user *fl,
>>  }
>>  
>>  static struct fastrpc_session_ctx *fastrpc_session_alloc(
>> -					struct fastrpc_channel_ctx *cctx)
>> +					struct fastrpc_user *fl)
>>  {
>> +	struct fastrpc_channel_ctx *cctx = fl->cctx;
>>  	struct fastrpc_session_ctx *session = NULL;
>>  	unsigned long flags;
>>  	int i;
>> @@ -1480,6 +1482,7 @@ static struct fastrpc_session_ctx *fastrpc_session_alloc(
>>  		if (!cctx->session[i].used && cctx->session[i].valid) {
>>  			cctx->session[i].used = true;
>>  			session = &cctx->session[i];
>> +			fl->client_id = FASTRPC_CLIENTID_MASK | i;
> So, it's not a mask, but a flag. Why is it necessary at all? Can you
> just pass i? Or i+1?
This also works as I just need to pass a non-zero unique identifier to DSP. I'll update this
in the next patch.

Thanks for reviewing.

--ekansh
>
>>  			break;
>>  		}
>>  	}
>> @@ -1504,7 +1507,7 @@ static int fastrpc_release_current_dsp_process(struct fastrpc_user *fl)
>>  	int tgid = 0;
>>  	u32 sc;
>>  
>> -	tgid = fl->tgid;
>> +	tgid = fl->client_id;
>>  	args[0].ptr = (u64)(uintptr_t) &tgid;
>>  	args[0].length = sizeof(tgid);
>>  	args[0].fd = -1;
>> @@ -1579,11 +1582,10 @@ static int fastrpc_device_open(struct inode *inode, struct file *filp)
>>  	INIT_LIST_HEAD(&fl->maps);
>>  	INIT_LIST_HEAD(&fl->mmaps);
>>  	INIT_LIST_HEAD(&fl->user);
>> -	fl->tgid = current->tgid;
>>  	fl->cctx = cctx;
>>  	fl->is_secure_dev = fdevice->secure;
>>  
>> -	fl->sctx = fastrpc_session_alloc(cctx);
>> +	fl->sctx = fastrpc_session_alloc(fl);
>>  	if (!fl->sctx) {
>>  		dev_err(&cctx->rpdev->dev, "No session available\n");
>>  		mutex_destroy(&fl->mutex);
>> @@ -1647,7 +1649,7 @@ static int fastrpc_dmabuf_alloc(struct fastrpc_user *fl, char __user *argp)
>>  static int fastrpc_init_attach(struct fastrpc_user *fl, int pd)
>>  {
>>  	struct fastrpc_invoke_args args[1];
>> -	int tgid = fl->tgid;
>> +	int tgid = fl->client_id;
>>  	u32 sc;
>>  
>>  	args[0].ptr = (u64)(uintptr_t) &tgid;
>> @@ -1803,7 +1805,7 @@ static int fastrpc_req_munmap_impl(struct fastrpc_user *fl, struct fastrpc_buf *
>>  	int err;
>>  	u32 sc;
>>  
>> -	req_msg.pgid = fl->tgid;
>> +	req_msg.pgid = fl->client_id;
>>  	req_msg.size = buf->size;
>>  	req_msg.vaddr = buf->raddr;
>>  
>> @@ -1889,7 +1891,7 @@ static int fastrpc_req_mmap(struct fastrpc_user *fl, char __user *argp)
>>  		return err;
>>  	}
>>  
>> -	req_msg.pgid = fl->tgid;
>> +	req_msg.pgid = fl->client_id;
>>  	req_msg.flags = req.flags;
>>  	req_msg.vaddr = req.vaddrin;
>>  	req_msg.num = sizeof(pages);
>> @@ -1978,7 +1980,7 @@ static int fastrpc_req_mem_unmap_impl(struct fastrpc_user *fl, struct fastrpc_me
>>  		return -EINVAL;
>>  	}
>>  
>> -	req_msg.pgid = fl->tgid;
>> +	req_msg.pgid = fl->client_id;
>>  	req_msg.len = map->len;
>>  	req_msg.vaddrin = map->raddr;
>>  	req_msg.fd = map->fd;
>> @@ -2031,7 +2033,7 @@ static int fastrpc_req_mem_map(struct fastrpc_user *fl, char __user *argp)
>>  		return err;
>>  	}
>>  
>> -	req_msg.pgid = fl->tgid;
>> +	req_msg.pgid = fl->client_id;
>>  	req_msg.fd = req.fd;
>>  	req_msg.offset = req.offset;
>>  	req_msg.vaddrin = req.vaddrin;
>> -- 
>> 2.34.1
>>



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