RE: [PATCH 2/5] staging:ti dspbridge: remove unnecessary check forNULL pointer in cmm.c

[Ramos Falcon, Ernesto]

>-----Original Message-----
>From: Menon, Nishanth
>Sent: Wednesday, July 28, 2010 10:32 AM
>To: Ramos Falcon, Ernesto
>Cc: gregkh@xxxxxxx; Ramirez Luna, Omar; ohad@xxxxxxxxxx;
>ameya.palande@xxxxxxxxx; felipe.contreras@xxxxxxxxx; Guzman Lugo, Fernando;
>linux-kernel@xxxxxxxxxxxxxxx; andy.shevchenko@xxxxxxxxx; linux-
>omap@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH 2/5] staging:ti dspbridge: remove unnecessary check for
>NULL pointer in cmm.c
>
>Nishanth Menon had written, on 07/28/2010 10:04 AM, the following:
>> Ramos Falcon, Ernesto had written, on 07/28/2010 09:40 AM, the following:
>>> Remove unnecessary check for NULL pointer in cmm.c.
>>>
>>> Signed-off-by: Ernesto Ramos <ernesto@xxxxxx>
>>> ---
>>>  drivers/staging/tidspbridge/pmgr/cmm.c |    8 ++------
>>>  1 files changed, 2 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/drivers/staging/tidspbridge/pmgr/cmm.c
>b/drivers/staging/tidspbridge/pmgr/cmm.c
>>> index 8e808d9..874ed64 100644
>>> --- a/drivers/staging/tidspbridge/pmgr/cmm.c
>>> +++ b/drivers/staging/tidspbridge/pmgr/cmm.c
>>> @@ -992,16 +992,12 @@ int cmm_xlator_create(struct cmm_xlatorobject
>**xlator,
>>>  int cmm_xlator_delete(struct cmm_xlatorobject *xlator, bool force)
>>>  {
>>>  	struct cmm_xlator *xlator_obj = (struct cmm_xlator *)xlator;
>>> -	int status = 0;
>>>
>>>  	DBC_REQUIRE(refs > 0);
>>>
>>> -	if (xlator_obj)
>>> -		kfree(xlator_obj);
>>> -	else
>>> -		status = -EFAULT;
>>> +	kfree(xlator_obj);
>>>
>>> -	return status;
>>> +	return 0;
>>>  }
>>>
>>>  /*
>> which kind of begs the question - does this function need to any longer
>> return int?
>>
>here is a better approach:
>remove cmm_xlator_delete altogether
>diff --git a/drivers/staging/tidspbridge/pmgr/cmm.c
>b/drivers/staging/tidspbridge/pmgr/cmm.c
>index 8e808d9..1a4ebca 100644
>--- a/drivers/staging/tidspbridge/pmgr/cmm.c
>+++ b/drivers/staging/tidspbridge/pmgr/cmm.c
>@@ -984,27 +984,6 @@ int cmm_xlator_create(struct cmm_xlatorobject
>**xlator,
>  }
>
>  /*
>- *  ======== cmm_xlator_delete ========
>- *  Purpose:
>- *      Free the Xlator resources.
>- *      VM gets freed later.
>- */
>-int cmm_xlator_delete(struct cmm_xlatorobject *xlator, bool force)
>-{
>-	struct cmm_xlator *xlator_obj = (struct cmm_xlator *)xlator;
>-	int status = 0;
>-
>-	DBC_REQUIRE(refs > 0);
>-
>-	if (xlator_obj)
>-		kfree(xlator_obj);
>-	else
>-		status = -EFAULT;
>-
>-	return status;
>-}
>-
>-/*
>   *  ======== cmm_xlator_alloc_buf ========
>   */
>  void *cmm_xlator_alloc_buf(struct cmm_xlatorobject *xlator, void *va_buf,
>diff --git a/drivers/staging/tidspbridge/rmgr/node.c
>b/drivers/staging/tidspbridge/rmgr/node.c
>index 9f07c81..0c39288 100644
>--- a/drivers/staging/tidspbridge/rmgr/node.c
>+++ b/drivers/staging/tidspbridge/rmgr/node.c
>@@ -2503,7 +2503,6 @@ static void delete_node(struct node_object *hnode,
>  			struct process_context *pr_ctxt)
>  {
>  	struct node_mgr *hnode_mgr;
>-	struct cmm_xlatorobject *xlator;
>  	struct bridge_drv_interface *intf_fxns;
>  	u32 i;
>  	enum node_type node_type;
>@@ -2521,7 +2520,6 @@ static void delete_node(struct node_object *hnode,
>  	hnode_mgr = hnode->hnode_mgr;
>  	if (!hnode_mgr)
>  		goto func_end;
>-	xlator = hnode->xlator;
>  	node_type = node_get_type(hnode);
>  	if (node_type != NODE_DEVICE) {
>  		node_msg_args = hnode->create_args.asa.node_msg_args;
>@@ -2617,10 +2615,7 @@ static void delete_node(struct node_object *hnode,
>  	hnode->dcd_props.obj_data.node_obj.pstr_i_alg_name = NULL;
>
>  	/* Free all SM address translator resources */
>-	if (xlator) {
>-		(void)cmm_xlator_delete(xlator, true);	/* force free */
>-		xlator = NULL;
>-	}
>+	kfree(hnode->xlator);
>
>  	kfree(hnode->nldr_node_obj);
>  	hnode->nldr_node_obj = NULL;
>diff --git a/drivers/staging/tidspbridge/rmgr/strm.c
>b/drivers/staging/tidspbridge/rmgr/strm.c
>index 73888e3..05a8d13 100644
>--- a/drivers/staging/tidspbridge/rmgr/strm.c
>+++ b/drivers/staging/tidspbridge/rmgr/strm.c
>@@ -844,14 +844,8 @@ static int delete_strm(struct strm_object *stream_obj)
>  			status = (*intf_fxns->pfn_chnl_close)
>  					(stream_obj->chnl_obj);
>  			/* Free all SM address translator resources */
>-			if (DSP_SUCCEEDED(status)) {
>-				if (stream_obj->xlator) {
>-					/* force free */
>-					(void)cmm_xlator_delete(stream_obj->
>-								xlator,
>-								true);
>-				}
>-			}
>+			if (DSP_SUCCEEDED(status))
>+				kfree(stream_obj->xlator);
>  		}
>  		kfree(stream_obj);
>  	} else {
>--
>Regards,
>Nishanth Menon

Thanks Nishanth,

I considered this approach before but in terms of maintainability I thought it was easier to locate where translator tables are destroy if we keep cmm_xlator_delete function.

/Ernesto
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