diff mbox

[2/3] DSPBRIDGE: Move resource cleanup to bridge_release

Message ID 1249478717-4446-2-git-send-email-ameya.palande@nokia.com (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Ameya Palande Aug. 5, 2009, 1:25 p.m. UTC 
Instead of doing lazy resource cleanup in bridge_open, this patch will move
it to bridge_release. This way the resources allocated will be cleaned up
when that instance of the open is closed and will not wait till the next
instance of open happens.

Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
Signed-off-by: Ameya Palande <ameya.palande@nokia.com>
---
 drivers/dsp/bridge/rmgr/drv_interface.c |  132 ++++++++++++-------------------
 1 files changed, 52 insertions(+), 80 deletions(-)

Comments

Ramos Falcon, Ernesto Aug. 5, 2009, 7:20 p.m. UTC | #1 
Hi,

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
> owner@vger.kernel.org] On Behalf Of Ameya Palande
> Sent: Wednesday, August 05, 2009 8:25 AM
> To: linux-omap@vger.kernel.org
> Cc: hiroshi.doyu@nokia.com; Guzman Lugo, Fernando; Ramirez Luna, Omar;
> roman.tereshonkov@nokia.com; Moogi, Suyog
> Subject: [PATCH 2/3] DSPBRIDGE: Move resource cleanup to bridge_release
> 
> Instead of doing lazy resource cleanup in bridge_open, this patch will
> move
> it to bridge_release. This way the resources allocated will be cleaned up
> when that instance of the open is closed and will not wait till the next
> instance of open happens.
> 
> Signed-off-by: Fernando Guzman Lugo <x0095840@ti.com>
> Signed-off-by: Ameya Palande <ameya.palande@nokia.com>
> ---
>  drivers/dsp/bridge/rmgr/drv_interface.c |  132 ++++++++++++--------------
> -----
>  1 files changed, 52 insertions(+), 80 deletions(-)
> 
> diff --git a/drivers/dsp/bridge/rmgr/drv_interface.c
> b/drivers/dsp/bridge/rmgr/drv_interface.c
> index 8cbdeee..2fcd6f9 100644
> --- a/drivers/dsp/bridge/rmgr/drv_interface.c
> +++ b/drivers/dsp/bridge/rmgr/drv_interface.c
> @@ -562,102 +562,74 @@ static void __exit bridge_exit(void)
>  	platform_driver_unregister(&bridge_driver);
>  }
> 
> -/* This function is called when an application opens handle to the
> - * bridge driver. */
> -
> +/*
> + * This function is called when an application opens handle to the
> + * bridge driver.
> + */
>  static int bridge_open(struct inode *ip, struct file *filp)
>  {
>  	int status = 0;
> -#ifndef RES_CLEANUP_DISABLE
> -       u32     hProcess;
> -	DSP_STATUS dsp_status = DSP_SOK;
> -	HANDLE	     hDrvObject = NULL;
> -	struct PROCESS_CONTEXT    *pPctxt = NULL;
> -	struct PROCESS_CONTEXT	*next_node = NULL;
> -	struct PROCESS_CONTEXT    *pCtxtclosed = NULL;
> -	struct PROCESS_CONTEXT    *pCtxttraverse = NULL;
> -	struct task_struct *tsk = NULL;
> -	GT_0trace(driverTrace, GT_ENTER, "-> driver_open\n");
> -	dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
> +	DSP_STATUS dsp_status;
> +	HANDLE hDrvObject;
> +	struct PROCESS_CONTEXT *pr_ctxt = NULL;
> 
> -	/* Checking weather task structure for all process existing
> -	 * in the process context list If not removing those processes*/
> -	if (DSP_FAILED(dsp_status))
> -		goto func_cont;
> +	GT_0trace(driverTrace, GT_ENTER, "-> bridge_open\n");
> 
> -	DRV_GetProcCtxtList(&pCtxtclosed, (struct DRV_OBJECT *)hDrvObject);
> -	while (pCtxtclosed != NULL) {
> -		tsk = find_task_by_vpid(pCtxtclosed->pid);
> -		next_node = pCtxtclosed->next;
> -
> -		if ((tsk == NULL) || (tsk->exit_state == EXIT_ZOMBIE)) {
> -
> -			GT_1trace(driverTrace, GT_5CLASS,
> -				 "***Task structure not existing for "
> -				 "process***%d\n", pCtxtclosed->pid);
> -			DRV_RemoveAllResources(pCtxtclosed);
> -			if (pCtxtclosed->hProcessor != NULL) {
> -				DRV_GetProcCtxtList(&pCtxttraverse,
> -					    (struct DRV_OBJECT *)hDrvObject);
> -				if (pCtxttraverse->next == NULL) {
> -					PROC_Detach(pCtxtclosed->hProcessor);
> -				} else {
> -					if ((pCtxtclosed->pid ==
> -					  pCtxttraverse->pid) &&
> -					  (pCtxttraverse->next != NULL)) {
> -						pCtxttraverse =
> -							pCtxttraverse->next;
> -					}
> -					while ((pCtxttraverse != NULL) &&
> -					     (pCtxtclosed->hProcessor
> -					     != pCtxttraverse->hProcessor)) {
> -						pCtxttraverse =
> -							pCtxttraverse->next;
> -						if ((pCtxttraverse != NULL) &&
> -						  (pCtxtclosed->pid ==
> -						  pCtxttraverse->pid)) {
> -							pCtxttraverse =
> -							   pCtxttraverse->next;
> -						}
> -					}
> -					if (pCtxttraverse == NULL) {
> -						PROC_Detach
> -						     (pCtxtclosed->hProcessor);
> -					}
> -				}
> -			}
> -			DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
> -					     pCtxtclosed,
> -					     (void *)pCtxtclosed->pid);
> +	dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
> +	if (DSP_SUCCEEDED(dsp_status)) {
> +		/*
> +		 * Allocate a new process context and insert it into global
> +		 * process context list.
> +		 */
> +		DRV_InsertProcContext(hDrvObject, &pr_ctxt);
> +		if (pr_ctxt) {
> +			DRV_ProcUpdatestate(pr_ctxt, PROC_RES_ALLOCATED);
> +			DRV_ProcSetPID(pr_ctxt, current->pid);
> +		} else {
> +			status = -ENOMEM;
>  		}
> -		pCtxtclosed = next_node;
> +	} else {
> +		status = -EIO;
>  	}
> -func_cont:
> -	dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
> -	if (DSP_SUCCEEDED(dsp_status))
> -		dsp_status = DRV_InsertProcContext(
> -				(struct DRV_OBJECT *)hDrvObject, &pPctxt);
> 
> -	if (pPctxt != NULL) {
> -			/* Return PID instead of process handle */
> -			hProcess = current->pid;
> +	filp->private_data = pr_ctxt;
> 
> -		DRV_ProcUpdatestate(pPctxt, PROC_RES_ALLOCATED);
> -			DRV_ProcSetPID(pPctxt, hProcess);
> -	}
> -#endif
> -
> -	GT_0trace(driverTrace, GT_ENTER, " <- driver_open\n");
> +	GT_0trace(driverTrace, GT_ENTER, "<- bridge_open\n");
>  	return status;
>  }
> 
> -/* This function is called when an application closes handle to the
> bridge
> - * driver. */
> +/*
> + * This function is called when an application closes handle to the
> bridge
> + * driver.
> + */
>  static int bridge_release(struct inode *ip, struct file *filp)
>  {
> +	int status = 0;
> +	DSP_STATUS dsp_status;
> +	HANDLE hDrvObject;
> +	struct PROCESS_CONTEXT *pr_ctxt;
> +
>  	GT_0trace(driverTrace, GT_ENTER, "-> bridge_release\n");
> +
> +	if (!filp->private_data) {
> +		status = -EIO;
> +	} else {
> +		pr_ctxt = filp->private_data;
> +		dsp_status = CFG_GetObject((u32 *)&hDrvObject,
> REG_DRV_OBJECT);
> +		if (DSP_SUCCEEDED(dsp_status)) {
> +			flush_signals(current);
> +			DRV_RemoveAllResources(pr_ctxt);
> +			PROC_Detach(pr_ctxt->hProcessor);
> +			DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
> +					pr_ctxt, (void *)pr_ctxt->pid);
> +		} else {
> +			status = -EIO;
> +		}
> +		filp->private_data = NULL;
> +	}
> +
>  	GT_0trace(driverTrace, GT_ENTER, "<- bridge_release\n");
> -	return 0;
> +	return status;
>  }
> 
>  /* This function provides IO interface to the bridge driver. */
> --
> 1.6.2.4
> 
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We have detected a use case where if an application creates a child process using fork call, and then the child and father processes call DSPProcessor_Attach() and create a new process context with new tgid; when the processes are terminated, only the last process calls bridge_release cleaning only the resources in the father process, leaving the child resources unreleased.

One solution we have seen is to perform goes through the entire process context list, clean up all the resources for all terminated processes or in "zombie" state, as below,

DRV_GetProcCtxtList(&pCtxtclosed, (struct DRV_OBJECT *)hDrvObject);
while (pCtxtclosed != NULL) {
	printk("pCtxtclosed->pid = %d\n",pCtxtclosed->pid);
	tsk = find_task_by_pid(pCtxtclosed->pid);

	if ((tsk == NULL) || (tsk->exit_state == EXIT_ZOMBIE)) {
	
		GT_1trace(driverTrace, GT_5CLASS,
			"***Task structure not existing for "
			 "process***%d\n", pCtxtclosed->pid);
		DRV_RemoveAllResources(pCtxtclosed);
		if (pCtxtclosed->hProcessor != NULL) {
					PROC_Detach
						 (pCtxtclosed->hProcessor);
		}
		pTmp = pCtxtclosed->next;
		DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
					 pCtxtclosed,
					 (void *)pCtxtclosed->pid);
	} else {
		pTmp = pCtxtclosed->next;
	}
	pCtxtclosed = pTmp;
}

Please let me know your comments.

/Ernesto
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Ameya Palande Aug. 5, 2009, 9:52 p.m. UTC | #2 
Hi Ernesto,

ext Ramos Falcon, Ernesto wrote:
> Hi,
> 
> We have detected a use case where if an application creates a child process using fork call, and then the child and father processes call DSPProcessor_Attach() and create a new process context with new tgid; when the processes are terminated, only the last process calls bridge_release cleaning only the resources in the father process, leaving the child resources unreleased.
> 
> One solution we have seen is to perform goes through the entire process context list, clean up all the resources for all terminated processes or in "zombie" state, as below,
> 
> DRV_GetProcCtxtList(&pCtxtclosed, (struct DRV_OBJECT *)hDrvObject);
> while (pCtxtclosed != NULL) {
> 	printk("pCtxtclosed->pid = %d\n",pCtxtclosed->pid);
> 	tsk = find_task_by_pid(pCtxtclosed->pid);
> 
> 	if ((tsk == NULL) || (tsk->exit_state == EXIT_ZOMBIE)) {
> 	
> 		GT_1trace(driverTrace, GT_5CLASS,
> 			"***Task structure not existing for "
> 			 "process***%d\n", pCtxtclosed->pid);
> 		DRV_RemoveAllResources(pCtxtclosed);
> 		if (pCtxtclosed->hProcessor != NULL) {
> 					PROC_Detach
> 						 (pCtxtclosed->hProcessor);
> 		}
> 		pTmp = pCtxtclosed->next;
> 		DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
> 					 pCtxtclosed,
> 					 (void *)pCtxtclosed->pid);
> 	} else {
> 		pTmp = pCtxtclosed->next;
> 	}
> 	pCtxtclosed = pTmp;
> }
> 
> Please let me know your comments.
> 
> /Ernesto

Good point :)

I would like to simplify this use case ;)

If we call DSPProcessor_Attach() twice in the same process and kill the process,
then it will leak memory for 1st instance of PROCESSOR object.

When we call open() on /dev/DspBridge a new PROCESS_CONTEXT is allocated, and it
should be allocated **only once** in bridge_open() unlike in NODE_Allocate() and
PROC_Attach(). PROCESS_CONTEXT tracks all the resources allocated on behalf of
an open file handle(and not the process / thread). When this handle is closed
all these resources should be freed in bridge_release(). Accountability of
resources should be done using PROCESS_CONTEXT and **not pid (which will be
different for different thread) / tgid (which will be different for parent and
child).

Above problem occurs because PROCESS_CONTEXT by design tracks only one PROCESSOR
object which gets freed in bridge_release().

Let me know your comments on this, and then we can proceed to fix this issue.

Cheers,
Ameya.
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Ramos Falcon, Ernesto Aug. 6, 2009, 6:06 p.m. UTC | #3 
Hi Ameya,

> -----Original Message-----
> From: Ameya Palande [mailto:ameya.palande@nokia.com]
> Sent: Wednesday, August 05, 2009 4:52 PM
> To: Ramos Falcon, Ernesto
> Cc: linux-omap@vger.kernel.org; Doyu Hiroshi (Nokia-D/Helsinki); Guzman
> Lugo, Fernando; Ramirez Luna, Omar; Tereshonkov Roman (Nokia-D/Helsinki);
> Moogi, Suyog
> Subject: Re: [PATCH 2/3] DSPBRIDGE: Move resource cleanup to
> bridge_release
> 
> Hi Ernesto,
> 
> ext Ramos Falcon, Ernesto wrote:
> > Hi,
> >
> > We have detected a use case where if an application creates a child
> process using fork call, and then the child and father processes call
> DSPProcessor_Attach() and create a new process context with new tgid; when
> the processes are terminated, only the last process calls bridge_release
> cleaning only the resources in the father process, leaving the child
> resources unreleased.
> >
> > One solution we have seen is to perform goes through the entire process
> context list, clean up all the resources for all terminated processes or
> in "zombie" state, as below,
> >
> > DRV_GetProcCtxtList(&pCtxtclosed, (struct DRV_OBJECT *)hDrvObject);
> > while (pCtxtclosed != NULL) {
> > 	printk("pCtxtclosed->pid = %d\n",pCtxtclosed->pid);
> > 	tsk = find_task_by_pid(pCtxtclosed->pid);
> >
> > 	if ((tsk == NULL) || (tsk->exit_state == EXIT_ZOMBIE)) {
> >
> > 		GT_1trace(driverTrace, GT_5CLASS,
> > 			"***Task structure not existing for "
> > 			 "process***%d\n", pCtxtclosed->pid);
> > 		DRV_RemoveAllResources(pCtxtclosed);
> > 		if (pCtxtclosed->hProcessor != NULL) {
> > 					PROC_Detach
> > 						 (pCtxtclosed->hProcessor);
> > 		}
> > 		pTmp = pCtxtclosed->next;
> > 		DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
> > 					 pCtxtclosed,
> > 					 (void *)pCtxtclosed->pid);
> > 	} else {
> > 		pTmp = pCtxtclosed->next;
> > 	}
> > 	pCtxtclosed = pTmp;
> > }
> >
> > Please let me know your comments.
> >
> > /Ernesto
> 
> Good point :)
> 
> I would like to simplify this use case ;)
> 
> If we call DSPProcessor_Attach() twice in the same process and kill the
> process,
> then it will leak memory for 1st instance of PROCESSOR object.
> 
> When we call open() on /dev/DspBridge a new PROCESS_CONTEXT is allocated,
> and it
> should be allocated **only once** in bridge_open() unlike in
> NODE_Allocate() and
> PROC_Attach(). PROCESS_CONTEXT tracks all the resources allocated on
> behalf of
> an open file handle(and not the process / thread). When this handle is
> closed
> all these resources should be freed in bridge_release(). Accountability of
> resources should be done using PROCESS_CONTEXT and **not pid (which will
> be
> different for different thread) / tgid (which will be different for parent
> and
> child).
> 
> Above problem occurs because PROCESS_CONTEXT by design tracks only one
> PROCESSOR
> object which gets freed in bridge_release().
> 
> Let me know your comments on this, and then we can proceed to fix this
> issue.
> 
> Cheers,
> Ameya.
You're right; I think using the PROCESS_CONTEXT to track the resources would resolve the issue. Also, with his approach we don't need to create a new context in the PROC_Attach /NODE_Allocate.

We can solve the issue by implementing a counter to track the number of calls to the PROC_Attach/Detach, so in that way we create a process handle only for the first time, and for the subsequent calls we need to return the existing handle. In the other hand PROC_Detach would be executed for the last call to this function.

I don't know yet how we would access or if there is an easy way to get the private_data as if get the pid using the "current", though.

/Ernesto
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Ameya Palande Aug. 6, 2009, 6:12 p.m. UTC | #4 
Hi Ernesto,

ext Ramos Falcon, Ernesto wrote:
> Hi Ameya,
> 
>> -----Original Message-----
>> From: Ameya Palande [mailto:ameya.palande@nokia.com]
>> Sent: Wednesday, August 05, 2009 4:52 PM
>> To: Ramos Falcon, Ernesto
>> Cc: linux-omap@vger.kernel.org; Doyu Hiroshi (Nokia-D/Helsinki); Guzman
>> Lugo, Fernando; Ramirez Luna, Omar; Tereshonkov Roman (Nokia-D/Helsinki);
>> Moogi, Suyog
>> Subject: Re: [PATCH 2/3] DSPBRIDGE: Move resource cleanup to
>> bridge_release
>>
>> Hi Ernesto,
>>
>> ext Ramos Falcon, Ernesto wrote:
>>> Hi,
>>>
>>> We have detected a use case where if an application creates a child
>> process using fork call, and then the child and father processes call
>> DSPProcessor_Attach() and create a new process context with new tgid; when
>> the processes are terminated, only the last process calls bridge_release
>> cleaning only the resources in the father process, leaving the child
>> resources unreleased.
>>> One solution we have seen is to perform goes through the entire process
>> context list, clean up all the resources for all terminated processes or
>> in "zombie" state, as below,
>>> DRV_GetProcCtxtList(&pCtxtclosed, (struct DRV_OBJECT *)hDrvObject);
>>> while (pCtxtclosed != NULL) {
>>> 	printk("pCtxtclosed->pid = %d\n",pCtxtclosed->pid);
>>> 	tsk = find_task_by_pid(pCtxtclosed->pid);
>>>
>>> 	if ((tsk == NULL) || (tsk->exit_state == EXIT_ZOMBIE)) {
>>>
>>> 		GT_1trace(driverTrace, GT_5CLASS,
>>> 			"***Task structure not existing for "
>>> 			 "process***%d\n", pCtxtclosed->pid);
>>> 		DRV_RemoveAllResources(pCtxtclosed);
>>> 		if (pCtxtclosed->hProcessor != NULL) {
>>> 					PROC_Detach
>>> 						 (pCtxtclosed->hProcessor);
>>> 		}
>>> 		pTmp = pCtxtclosed->next;
>>> 		DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
>>> 					 pCtxtclosed,
>>> 					 (void *)pCtxtclosed->pid);
>>> 	} else {
>>> 		pTmp = pCtxtclosed->next;
>>> 	}
>>> 	pCtxtclosed = pTmp;
>>> }
>>>
>>> Please let me know your comments.
>>>
>>> /Ernesto
>> Good point :)
>>
>> I would like to simplify this use case ;)
>>
>> If we call DSPProcessor_Attach() twice in the same process and kill the
>> process,
>> then it will leak memory for 1st instance of PROCESSOR object.
>>
>> When we call open() on /dev/DspBridge a new PROCESS_CONTEXT is allocated,
>> and it
>> should be allocated **only once** in bridge_open() unlike in
>> NODE_Allocate() and
>> PROC_Attach(). PROCESS_CONTEXT tracks all the resources allocated on
>> behalf of
>> an open file handle(and not the process / thread). When this handle is
>> closed
>> all these resources should be freed in bridge_release(). Accountability of
>> resources should be done using PROCESS_CONTEXT and **not pid (which will
>> be
>> different for different thread) / tgid (which will be different for parent
>> and
>> child).
>>
>> Above problem occurs because PROCESS_CONTEXT by design tracks only one
>> PROCESSOR
>> object which gets freed in bridge_release().
>>
>> Let me know your comments on this, and then we can proceed to fix this
>> issue.
>>
>> Cheers,
>> Ameya.
> You're right; I think using the PROCESS_CONTEXT to track the resources would resolve the issue. Also, with his approach we don't need to create a new context in the PROC_Attach /NODE_Allocate.
> 
> We can solve the issue by implementing a counter to track the number of calls to the PROC_Attach/Detach, so in that way we create a process handle only for the first time, and for the subsequent calls we need to return the existing handle. In the other hand PROC_Detach would be executed for the last call to this function.
> 
> I don't know yet how we would access or if there is an easy way to get the private_data as if get the pid using the "current", though.
> 
> /Ernesto

Thanks for your comment :)
I am working on this and will try to provide a solution by 10th Aug 2009.

Cheers,
Ameya.
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diff mbox

Patch

diff --git a/drivers/dsp/bridge/rmgr/drv_interface.c b/drivers/dsp/bridge/rmgr/drv_interface.c
index 8cbdeee..2fcd6f9 100644
--- a/drivers/dsp/bridge/rmgr/drv_interface.c
+++ b/drivers/dsp/bridge/rmgr/drv_interface.c
@@ -562,102 +562,74 @@  static void __exit bridge_exit(void)
 	platform_driver_unregister(&bridge_driver);
 }
 
-/* This function is called when an application opens handle to the
- * bridge driver. */
-
+/*
+ * This function is called when an application opens handle to the
+ * bridge driver.
+ */
 static int bridge_open(struct inode *ip, struct file *filp)
 {
 	int status = 0;
-#ifndef RES_CLEANUP_DISABLE
-       u32     hProcess;
-	DSP_STATUS dsp_status = DSP_SOK;
-	HANDLE	     hDrvObject = NULL;
-	struct PROCESS_CONTEXT    *pPctxt = NULL;
-	struct PROCESS_CONTEXT	*next_node = NULL;
-	struct PROCESS_CONTEXT    *pCtxtclosed = NULL;
-	struct PROCESS_CONTEXT    *pCtxttraverse = NULL;
-	struct task_struct *tsk = NULL;
-	GT_0trace(driverTrace, GT_ENTER, "-> driver_open\n");
-	dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
+	DSP_STATUS dsp_status;
+	HANDLE hDrvObject;
+	struct PROCESS_CONTEXT *pr_ctxt = NULL;
 
-	/* Checking weather task structure for all process existing
-	 * in the process context list If not removing those processes*/
-	if (DSP_FAILED(dsp_status))
-		goto func_cont;
+	GT_0trace(driverTrace, GT_ENTER, "-> bridge_open\n");
 
-	DRV_GetProcCtxtList(&pCtxtclosed, (struct DRV_OBJECT *)hDrvObject);
-	while (pCtxtclosed != NULL) {
-		tsk = find_task_by_vpid(pCtxtclosed->pid);
-		next_node = pCtxtclosed->next;
-
-		if ((tsk == NULL) || (tsk->exit_state == EXIT_ZOMBIE)) {
-
-			GT_1trace(driverTrace, GT_5CLASS,
-				 "***Task structure not existing for "
-				 "process***%d\n", pCtxtclosed->pid);
-			DRV_RemoveAllResources(pCtxtclosed);
-			if (pCtxtclosed->hProcessor != NULL) {
-				DRV_GetProcCtxtList(&pCtxttraverse,
-					    (struct DRV_OBJECT *)hDrvObject);
-				if (pCtxttraverse->next == NULL) {
-					PROC_Detach(pCtxtclosed->hProcessor);
-				} else {
-					if ((pCtxtclosed->pid ==
-					  pCtxttraverse->pid) &&
-					  (pCtxttraverse->next != NULL)) {
-						pCtxttraverse =
-							pCtxttraverse->next;
-					}
-					while ((pCtxttraverse != NULL) &&
-					     (pCtxtclosed->hProcessor
-					     != pCtxttraverse->hProcessor)) {
-						pCtxttraverse =
-							pCtxttraverse->next;
-						if ((pCtxttraverse != NULL) &&
-						  (pCtxtclosed->pid ==
-						  pCtxttraverse->pid)) {
-							pCtxttraverse =
-							   pCtxttraverse->next;
-						}
-					}
-					if (pCtxttraverse == NULL) {
-						PROC_Detach
-						     (pCtxtclosed->hProcessor);
-					}
-				}
-			}
-			DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
-					     pCtxtclosed,
-					     (void *)pCtxtclosed->pid);
+	dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
+	if (DSP_SUCCEEDED(dsp_status)) {
+		/*
+		 * Allocate a new process context and insert it into global
+		 * process context list.
+		 */
+		DRV_InsertProcContext(hDrvObject, &pr_ctxt);
+		if (pr_ctxt) {
+			DRV_ProcUpdatestate(pr_ctxt, PROC_RES_ALLOCATED);
+			DRV_ProcSetPID(pr_ctxt, current->pid);
+		} else {
+			status = -ENOMEM;
 		}
-		pCtxtclosed = next_node;
+	} else {
+		status = -EIO;
 	}
-func_cont:
-	dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
-	if (DSP_SUCCEEDED(dsp_status))
-		dsp_status = DRV_InsertProcContext(
-				(struct DRV_OBJECT *)hDrvObject, &pPctxt);
 
-	if (pPctxt != NULL) {
-			/* Return PID instead of process handle */
-			hProcess = current->pid;
+	filp->private_data = pr_ctxt;
 
-		DRV_ProcUpdatestate(pPctxt, PROC_RES_ALLOCATED);
-			DRV_ProcSetPID(pPctxt, hProcess);
-	}
-#endif
-
-	GT_0trace(driverTrace, GT_ENTER, " <- driver_open\n");
+	GT_0trace(driverTrace, GT_ENTER, "<- bridge_open\n");
 	return status;
 }
 
-/* This function is called when an application closes handle to the bridge
- * driver. */
+/*
+ * This function is called when an application closes handle to the bridge
+ * driver.
+ */
 static int bridge_release(struct inode *ip, struct file *filp)
 {
+	int status = 0;
+	DSP_STATUS dsp_status;
+	HANDLE hDrvObject;
+	struct PROCESS_CONTEXT *pr_ctxt;
+
 	GT_0trace(driverTrace, GT_ENTER, "-> bridge_release\n");
+
+	if (!filp->private_data) {
+		status = -EIO;
+	} else {
+		pr_ctxt = filp->private_data;
+		dsp_status = CFG_GetObject((u32 *)&hDrvObject, REG_DRV_OBJECT);
+		if (DSP_SUCCEEDED(dsp_status)) {
+			flush_signals(current);
+			DRV_RemoveAllResources(pr_ctxt);
+			PROC_Detach(pr_ctxt->hProcessor);
+			DRV_RemoveProcContext((struct DRV_OBJECT *)hDrvObject,
+					pr_ctxt, (void *)pr_ctxt->pid);
+		} else {
+			status = -EIO;
+		}
+		filp->private_data = NULL;
+	}
+
 	GT_0trace(driverTrace, GT_ENTER, "<- bridge_release\n");
-	return 0;
+	return status;
 }
 
 /* This function provides IO interface to the bridge driver. */