diff mbox series

[v4,2/2] tpm: add support for nonblocking operation

Message ID 153367366969.18015.14742040525393494830.stgit@tstruk-mobl1.jf.intel.com (mailing list archive)
State New, archived
Headers show
Series tpm: add support for nonblocking operation | expand

Commit Message

Tadeusz Struk Aug. 7, 2018, 8:27 p.m. UTC
Currently the TPM driver only supports blocking calls, which doesn't allow
asynchronous IO operations to the TPM hardware.
This patch changes it and adds support for nonblocking write and a new poll
function to enable applications, which want to take advantage of this.

Tested-by: Philip Tricca <philip.b.tricca@intel.com>
Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
---
 drivers/char/tpm/tpm-dev-common.c |  149 ++++++++++++++++++++++++++++---------
 drivers/char/tpm/tpm-dev.c        |   16 +++-
 drivers/char/tpm/tpm-dev.h        |   17 +++-
 drivers/char/tpm/tpm-interface.c  |    1 
 drivers/char/tpm/tpm.h            |    1 
 drivers/char/tpm/tpmrm-dev.c      |   19 +++--
 6 files changed, 150 insertions(+), 53 deletions(-)

Comments

Jarkko Sakkinen Aug. 10, 2018, 5:43 p.m. UTC | #1
On Tue, Aug 07, 2018 at 01:27:49PM -0700, Tadeusz Struk wrote:
> Currently the TPM driver only supports blocking calls, which doesn't allow
> asynchronous IO operations to the TPM hardware.
> This patch changes it and adds support for nonblocking write and a new poll
> function to enable applications, which want to take advantage of this.
> 
> Tested-by: Philip Tricca <philip.b.tricca@intel.com>
> Signed-off-by: Tadeusz Struk <tadeusz.struk@intel.com>
> ---
>  drivers/char/tpm/tpm-dev-common.c |  149 ++++++++++++++++++++++++++++---------
>  drivers/char/tpm/tpm-dev.c        |   16 +++-
>  drivers/char/tpm/tpm-dev.h        |   17 +++-
>  drivers/char/tpm/tpm-interface.c  |    1 
>  drivers/char/tpm/tpm.h            |    1 
>  drivers/char/tpm/tpmrm-dev.c      |   19 +++--
>  6 files changed, 150 insertions(+), 53 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
> index f0c033b69b62..f71d80b94451 100644
> --- a/drivers/char/tpm/tpm-dev-common.c
> +++ b/drivers/char/tpm/tpm-dev-common.c
> @@ -17,11 +17,36 @@
>   * License.
>   *
>   */
> +#include <linux/poll.h>
>  #include <linux/slab.h>
>  #include <linux/uaccess.h>
> +#include <linux/workqueue.h>
>  #include "tpm.h"
>  #include "tpm-dev.h"
>  
> +static struct workqueue_struct *tpm_dev_wq;

A naming contradiction with tpm_common_read() and tpm_common_write(). To
sort that up I would suggest adding a commit to the patch set that
renames these functions as tpm_dev_common_read() and
tpm_dev_common_write() and use the name tpm_common_dev_wq here.

> +static DEFINE_MUTEX(tpm_dev_wq_lock);

This is an unacceptable way to do it, Rather add:

int __init  tpm_dev_common_init(void)
{
	tpm_dev_common_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
	if (!tpm_dev_common_wq)
		return -ENOMEM;

	return 0;
}

and call this in the driver initialization.

> +
> +static void tpm_async_work(struct work_struct *work)
> +{
> +	struct file_priv *priv =
> +			container_of(work, struct file_priv, async_work);
> +	ssize_t ret;
> +
> +	mutex_lock(&priv->buffer_mutex);
> +	priv->command_enqueued = false;
> +	ret = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
> +			   sizeof(priv->data_buffer), 0);
> +
> +	tpm_put_ops(priv->chip);
> +	if (ret > 0) {
> +		priv->data_pending = ret;
> +		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
> +	}
> +	mutex_unlock(&priv->buffer_mutex);
> +	wake_up_interruptible(&priv->async_wait);
> +}
> +
>  static void user_reader_timeout(struct timer_list *t)
>  {
>  	struct file_priv *priv = from_timer(priv, t, user_read_timer);
> @@ -29,30 +54,44 @@ static void user_reader_timeout(struct timer_list *t)
>  	pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
>  		task_tgid_nr(current));
>  
> -	schedule_work(&priv->work);
> +	schedule_work(&priv->timeout_work);
>  }
>  
> -static void timeout_work(struct work_struct *work)
> +static void tpm_timeout_work(struct work_struct *work)
>  {
> -	struct file_priv *priv = container_of(work, struct file_priv, work);
> +	struct file_priv *priv = container_of(work, struct file_priv,
> +					      timeout_work);
>  
>  	mutex_lock(&priv->buffer_mutex);
>  	priv->data_pending = 0;
>  	memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
>  	mutex_unlock(&priv->buffer_mutex);
> +	wake_up_interruptible(&priv->async_wait);
>  }
>  
> -void tpm_common_open(struct file *file, struct tpm_chip *chip,
> -		     struct file_priv *priv, struct tpm_space *space)
> +int tpm_common_open(struct file *file, struct tpm_chip *chip,
> +		    struct file_priv *priv, struct tpm_space *space)
>  {
>  	priv->chip = chip;
>  	priv->space = space;
>  
>  	mutex_init(&priv->buffer_mutex);
>  	timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
> -	INIT_WORK(&priv->work, timeout_work);
> -
> +	INIT_WORK(&priv->timeout_work, tpm_timeout_work);
> +	INIT_WORK(&priv->async_work, tpm_async_work);
> +	init_waitqueue_head(&priv->async_wait);
>  	file->private_data = priv;
> +	mutex_lock(&tpm_dev_wq_lock);
> +	if (!tpm_dev_wq) {
> +		tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
> +		if (!tpm_dev_wq) {
> +			mutex_unlock(&tpm_dev_wq_lock);
> +			return -ENOMEM;
> +		}
> +	}
> +
> +	mutex_unlock(&tpm_dev_wq_lock);
> +	return 0;
>  }
>  
>  ssize_t tpm_common_read(struct file *file, char __user *buf,
> @@ -63,15 +102,17 @@ ssize_t tpm_common_read(struct file *file, char __user *buf,
>  	int rc;
>  
>  	del_singleshot_timer_sync(&priv->user_read_timer);
> -	flush_work(&priv->work);
> +	flush_work(&priv->timeout_work);
>  	mutex_lock(&priv->buffer_mutex);
>  
>  	if (priv->data_pending) {
>  		ret_size = min_t(ssize_t, size, priv->data_pending);
> -		rc = copy_to_user(buf, priv->data_buffer, ret_size);
> -		memset(priv->data_buffer, 0, priv->data_pending);
> -		if (rc)
> -			ret_size = -EFAULT;
> +		if (ret_size > 0) {
> +			rc = copy_to_user(buf, priv->data_buffer, ret_size);
> +			memset(priv->data_buffer, 0, priv->data_pending);
> +			if (rc)
> +				ret_size = -EFAULT;
> +		}
>  
>  		priv->data_pending = 0;
>  	}
> @@ -84,10 +125,9 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
>  			 size_t size, loff_t *off)
>  {
>  	struct file_priv *priv = file->private_data;
> -	size_t in_size = size;

/Jarkko
Tadeusz Struk Aug. 10, 2018, 6:21 p.m. UTC | #2
On 08/10/2018 10:43 AM, Jarkko Sakkinen wrote:
>> +static struct workqueue_struct *tpm_dev_wq;
> A naming contradiction with tpm_common_read() and tpm_common_write(). To
> sort that up I would suggest adding a commit to the patch set that
> renames these functions as tpm_dev_common_read() and
> tpm_dev_common_write() and use the name tpm_common_dev_wq here.
> 

Currently we have: tpm_open(), tpm_write(), tpm_release() in tpm-dev.c
tpmrm_open(), tpmrm_read(), tpmrm_write(), tpmrm_release() in tpmrm-dev.c
tpm_common_open(), tpm_common_read(), tpm_common_write(), tpm_common_release() in tpm-dev-common.c

I think that's pretty consistent. Do you want me to rename all of them to tpm_dev_*()?
I don't see any value in doing this. What about if I just rename: 
tpm_dev_wq_lock to tpm_common_wq_lock, and tpm_dev_wq to tpm_common_wq?

>> +static DEFINE_MUTEX(tpm_dev_wq_lock);
> This is an unacceptable way to do it, Rather add:
> 
> int __init  tpm_dev_common_init(void)
> {
> 	tpm_dev_common_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
> 	if (!tpm_dev_common_wq)
> 		return -ENOMEM;
> 
> 	return 0;
> }
> 
> and call this in the driver initialization.
> 
That was the way it was implemented in v1 https://patchwork.kernel.org/patch/10442125/

See: static int __init tpm_dev_common_init(void)

and the feedback I got from Jason was:

"I wonder if it is worth creating this when the first file is
opened.. Lots of systems have TPMs but few use the userspace.."

so I changed this to allocate the WQ on first open. I think it makes sense,
but I leave it to you to decide.

Tadeusz,
James Bottomley Aug. 10, 2018, 6:48 p.m. UTC | #3
On Fri, 2018-08-10 at 11:21 -0700, Tadeusz Struk wrote:
> and the feedback I got from Jason was:
> 
> "I wonder if it is worth creating this when the first file is
> opened.. Lots of systems have TPMs but few use the userspace.."
> 
> so I changed this to allocate the WQ on first open. I think it makes
> sense, but I leave it to you to decide.

If the reason is to not create a wq unless it's needed, shouldn't the
condition actually be first open with flag O_NONBLOCK?

James
Tadeusz Struk Aug. 10, 2018, 6:56 p.m. UTC | #4
On 08/10/2018 11:48 AM, James Bottomley wrote:
> On Fri, 2018-08-10 at 11:21 -0700, Tadeusz Struk wrote:
>> and the feedback I got from Jason was:
>>
>> "I wonder if it is worth creating this when the first file is
>> opened.. Lots of systems have TPMs but few use the userspace.."
>>
>> so I changed this to allocate the WQ on first open. I think it makes
>> sense, but I leave it to you to decide.
> 
> If the reason is to not create a wq unless it's needed, shouldn't the
> condition actually be first open with flag O_NONBLOCK?
> 

Not really because one can do:

int fd = open("/dev/tpm0", O_RDWR);
fcntl(fd, F_SETFL, O_NONBLOCK);
James Bottomley Aug. 10, 2018, 7 p.m. UTC | #5
On Fri, 2018-08-10 at 11:56 -0700, Tadeusz Struk wrote:
> On 08/10/2018 11:48 AM, James Bottomley wrote:
> > On Fri, 2018-08-10 at 11:21 -0700, Tadeusz Struk wrote:
> > > and the feedback I got from Jason was:
> > > 
> > > "I wonder if it is worth creating this when the first file is
> > > opened.. Lots of systems have TPMs but few use the userspace.."
> > > 
> > > so I changed this to allocate the WQ on first open. I think it
> > > makes sense, but I leave it to you to decide.
> > 
> > If the reason is to not create a wq unless it's needed, shouldn't
> > the condition actually be first open with flag O_NONBLOCK?
> > 
> 
> Not really because one can do:
> 
> int fd = open("/dev/tpm0", O_RDWR);
> fcntl(fd, F_SETFL, O_NONBLOCK);

so move the condition to first need to queue ...

James
Tadeusz Struk Aug. 10, 2018, 7:14 p.m. UTC | #6
On 08/10/2018 12:00 PM, James Bottomley wrote:
> On Fri, 2018-08-10 at 11:56 -0700, Tadeusz Struk wrote:
>> On 08/10/2018 11:48 AM, James Bottomley wrote:
>>> On Fri, 2018-08-10 at 11:21 -0700, Tadeusz Struk wrote:
>>>> and the feedback I got from Jason was:
>>>>
>>>> "I wonder if it is worth creating this when the first file is
>>>> opened.. Lots of systems have TPMs but few use the userspace.."
>>>>
>>>> so I changed this to allocate the WQ on first open. I think it
>>>> makes sense, but I leave it to you to decide.
>>>
>>> If the reason is to not create a wq unless it's needed, shouldn't
>>> the condition actually be first open with flag O_NONBLOCK?
>>>
>>
>> Not really because one can do:
>>
>> int fd = open("/dev/tpm0", O_RDWR);
>> fcntl(fd, F_SETFL, O_NONBLOCK);
> 
> so move the condition to first need to queue ...
> 

That would work, even though this is not how this is usually done.
The first open looks like the sweet spot between module init
and first need to queue.
Thanks,
Jarkko Sakkinen Aug. 12, 2018, 10:39 a.m. UTC | #7
On Fri, Aug 10, 2018 at 11:21:14AM -0700, Tadeusz Struk wrote:
> On 08/10/2018 10:43 AM, Jarkko Sakkinen wrote:
> >> +static struct workqueue_struct *tpm_dev_wq;
> > A naming contradiction with tpm_common_read() and tpm_common_write(). To
> > sort that up I would suggest adding a commit to the patch set that
> > renames these functions as tpm_dev_common_read() and
> > tpm_dev_common_write() and use the name tpm_common_dev_wq here.
> > 
> 
> Currently we have: tpm_open(), tpm_write(), tpm_release() in tpm-dev.c
> tpmrm_open(), tpmrm_read(), tpmrm_write(), tpmrm_release() in tpmrm-dev.c
> tpm_common_open(), tpm_common_read(), tpm_common_write(), tpm_common_release() in tpm-dev-common.c
> 
> I think that's pretty consistent. Do you want me to rename all of them to tpm_dev_*()?
> I don't see any value in doing this. What about if I just rename: 
> tpm_dev_wq_lock to tpm_common_wq_lock, and tpm_dev_wq to tpm_common_wq?

That is good enough. At least it is consistent.

> >> +static DEFINE_MUTEX(tpm_dev_wq_lock);
> > This is an unacceptable way to do it, Rather add:
> > 
> > int __init  tpm_dev_common_init(void)
> > {
> > 	tpm_dev_common_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
> > 	if (!tpm_dev_common_wq)
> > 		return -ENOMEM;
> > 
> > 	return 0;
> > }
> > 
> > and call this in the driver initialization.
> > 
> That was the way it was implemented in v1 https://patchwork.kernel.org/patch/10442125/
> 
> See: static int __init tpm_dev_common_init(void)
> 
> and the feedback I got from Jason was:
> 
> "I wonder if it is worth creating this when the first file is
> opened.. Lots of systems have TPMs but few use the userspace.."
> 
> so I changed this to allocate the WQ on first open. I think it makes sense,
> but I leave it to you to decide.

Without a question I would go with tpm_common_init() for stability (one
less point of failure in open) and simplicity (no need for a locking
scheme).

> Tadeusz,
> -- 
> Tadeusz

/Jarkko
diff mbox series

Patch

diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index f0c033b69b62..f71d80b94451 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -17,11 +17,36 @@ 
  * License.
  *
  */
+#include <linux/poll.h>
 #include <linux/slab.h>
 #include <linux/uaccess.h>
+#include <linux/workqueue.h>
 #include "tpm.h"
 #include "tpm-dev.h"
 
+static struct workqueue_struct *tpm_dev_wq;
+static DEFINE_MUTEX(tpm_dev_wq_lock);
+
+static void tpm_async_work(struct work_struct *work)
+{
+	struct file_priv *priv =
+			container_of(work, struct file_priv, async_work);
+	ssize_t ret;
+
+	mutex_lock(&priv->buffer_mutex);
+	priv->command_enqueued = false;
+	ret = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
+			   sizeof(priv->data_buffer), 0);
+
+	tpm_put_ops(priv->chip);
+	if (ret > 0) {
+		priv->data_pending = ret;
+		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
+	}
+	mutex_unlock(&priv->buffer_mutex);
+	wake_up_interruptible(&priv->async_wait);
+}
+
 static void user_reader_timeout(struct timer_list *t)
 {
 	struct file_priv *priv = from_timer(priv, t, user_read_timer);
@@ -29,30 +54,44 @@  static void user_reader_timeout(struct timer_list *t)
 	pr_warn("TPM user space timeout is deprecated (pid=%d)\n",
 		task_tgid_nr(current));
 
-	schedule_work(&priv->work);
+	schedule_work(&priv->timeout_work);
 }
 
-static void timeout_work(struct work_struct *work)
+static void tpm_timeout_work(struct work_struct *work)
 {
-	struct file_priv *priv = container_of(work, struct file_priv, work);
+	struct file_priv *priv = container_of(work, struct file_priv,
+					      timeout_work);
 
 	mutex_lock(&priv->buffer_mutex);
 	priv->data_pending = 0;
 	memset(priv->data_buffer, 0, sizeof(priv->data_buffer));
 	mutex_unlock(&priv->buffer_mutex);
+	wake_up_interruptible(&priv->async_wait);
 }
 
-void tpm_common_open(struct file *file, struct tpm_chip *chip,
-		     struct file_priv *priv, struct tpm_space *space)
+int tpm_common_open(struct file *file, struct tpm_chip *chip,
+		    struct file_priv *priv, struct tpm_space *space)
 {
 	priv->chip = chip;
 	priv->space = space;
 
 	mutex_init(&priv->buffer_mutex);
 	timer_setup(&priv->user_read_timer, user_reader_timeout, 0);
-	INIT_WORK(&priv->work, timeout_work);
-
+	INIT_WORK(&priv->timeout_work, tpm_timeout_work);
+	INIT_WORK(&priv->async_work, tpm_async_work);
+	init_waitqueue_head(&priv->async_wait);
 	file->private_data = priv;
+	mutex_lock(&tpm_dev_wq_lock);
+	if (!tpm_dev_wq) {
+		tpm_dev_wq = alloc_workqueue("tpm_dev_wq", WQ_MEM_RECLAIM, 0);
+		if (!tpm_dev_wq) {
+			mutex_unlock(&tpm_dev_wq_lock);
+			return -ENOMEM;
+		}
+	}
+
+	mutex_unlock(&tpm_dev_wq_lock);
+	return 0;
 }
 
 ssize_t tpm_common_read(struct file *file, char __user *buf,
@@ -63,15 +102,17 @@  ssize_t tpm_common_read(struct file *file, char __user *buf,
 	int rc;
 
 	del_singleshot_timer_sync(&priv->user_read_timer);
-	flush_work(&priv->work);
+	flush_work(&priv->timeout_work);
 	mutex_lock(&priv->buffer_mutex);
 
 	if (priv->data_pending) {
 		ret_size = min_t(ssize_t, size, priv->data_pending);
-		rc = copy_to_user(buf, priv->data_buffer, ret_size);
-		memset(priv->data_buffer, 0, priv->data_pending);
-		if (rc)
-			ret_size = -EFAULT;
+		if (ret_size > 0) {
+			rc = copy_to_user(buf, priv->data_buffer, ret_size);
+			memset(priv->data_buffer, 0, priv->data_pending);
+			if (rc)
+				ret_size = -EFAULT;
+		}
 
 		priv->data_pending = 0;
 	}
@@ -84,10 +125,9 @@  ssize_t tpm_common_write(struct file *file, const char __user *buf,
 			 size_t size, loff_t *off)
 {
 	struct file_priv *priv = file->private_data;
-	size_t in_size = size;
-	ssize_t out_size;
+	int ret = 0;
 
-	if (in_size > TPM_BUFSIZE)
+	if (size > TPM_BUFSIZE)
 		return -E2BIG;
 
 	mutex_lock(&priv->buffer_mutex);
@@ -96,21 +136,20 @@  ssize_t tpm_common_write(struct file *file, const char __user *buf,
 	 * tpm_read or a user_read_timer timeout. This also prevents split
 	 * buffered writes from blocking here.
 	 */
-	if (priv->data_pending != 0) {
-		mutex_unlock(&priv->buffer_mutex);
-		return -EBUSY;
+	if (priv->data_pending != 0 || priv->command_enqueued) {
+		ret = -EBUSY;
+		goto out;
 	}
 
-	if (copy_from_user
-	    (priv->data_buffer, (void __user *) buf, in_size)) {
-		mutex_unlock(&priv->buffer_mutex);
-		return -EFAULT;
+	if (copy_from_user(priv->data_buffer, buf, size)) {
+		ret = -EFAULT;
+		goto out;
 	}
 
-	if (in_size < 6 ||
-	    in_size < be32_to_cpu(*((__be32 *) (priv->data_buffer + 2)))) {
-		mutex_unlock(&priv->buffer_mutex);
-		return -EINVAL;
+	if (size < 6 ||
+	    size < be32_to_cpu(*((__be32 *)(priv->data_buffer + 2)))) {
+		ret = -EINVAL;
+		goto out;
 	}
 
 	/* atomic tpm command send and result receive. We only hold the ops
@@ -118,25 +157,50 @@  ssize_t tpm_common_write(struct file *file, const char __user *buf,
 	 * the char dev is held open.
 	 */
 	if (tpm_try_get_ops(priv->chip)) {
-		mutex_unlock(&priv->buffer_mutex);
-		return -EPIPE;
+		ret = -EPIPE;
+		goto out;
 	}
-	out_size = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
-				sizeof(priv->data_buffer), 0);
 
-	tpm_put_ops(priv->chip);
-	if (out_size < 0) {
+	/*
+	 * If in nonblocking mode schedule an async job to send
+	 * the command return the size.
+	 * In case of error the err code will be returned in
+	 * the subsequent read call.
+	 */
+	if (file->f_flags & O_NONBLOCK) {
+		priv->command_enqueued = true;
+		queue_work(tpm_dev_wq, &priv->async_work);
 		mutex_unlock(&priv->buffer_mutex);
-		return out_size;
+		return size;
 	}
 
-	priv->data_pending = out_size;
+	ret = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
+			   sizeof(priv->data_buffer), 0);
+	tpm_put_ops(priv->chip);
+
+	if (ret > 0) {
+		priv->data_pending = ret;
+		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
+		ret = size;
+	}
+out:
 	mutex_unlock(&priv->buffer_mutex);
+	return ret;
+}
 
-	/* Set a timeout by which the reader must come claim the result */
-	mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
+__poll_t tpm_common_poll(struct file *file, poll_table *wait)
+{
+	struct file_priv *priv = file->private_data;
+	__poll_t mask = 0;
+
+	poll_wait(file, &priv->async_wait, wait);
 
-	return in_size;
+	if (priv->data_pending)
+		mask = EPOLLIN | EPOLLRDNORM;
+	else
+		mask = EPOLLOUT | EPOLLWRNORM;
+
+	return mask;
 }
 
 /*
@@ -144,8 +208,17 @@  ssize_t tpm_common_write(struct file *file, const char __user *buf,
  */
 void tpm_common_release(struct file *file, struct file_priv *priv)
 {
+	flush_work(&priv->async_work);
 	del_singleshot_timer_sync(&priv->user_read_timer);
-	flush_work(&priv->work);
+	flush_work(&priv->timeout_work);
 	file->private_data = NULL;
 	priv->data_pending = 0;
 }
+
+void __exit tpm_dev_common_exit(void)
+{
+	if (tpm_dev_wq) {
+		destroy_workqueue(tpm_dev_wq);
+		tpm_dev_wq = NULL;
+	}
+}
diff --git a/drivers/char/tpm/tpm-dev.c b/drivers/char/tpm/tpm-dev.c
index 98b9630c3a36..1e353a4f4b7e 100644
--- a/drivers/char/tpm/tpm-dev.c
+++ b/drivers/char/tpm/tpm-dev.c
@@ -24,6 +24,7 @@  static int tpm_open(struct inode *inode, struct file *file)
 {
 	struct tpm_chip *chip;
 	struct file_priv *priv;
+	int rc = -ENOMEM;
 
 	chip = container_of(inode->i_cdev, struct tpm_chip, cdev);
 
@@ -37,15 +38,21 @@  static int tpm_open(struct inode *inode, struct file *file)
 
 	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 	if (priv == NULL)
-		goto out;
+		goto out_clear;
 
-	tpm_common_open(file, chip, priv, NULL);
+	rc = tpm_common_open(file, chip, priv, NULL);
+	if (rc)
+		goto out_free;
 
 	return 0;
 
- out:
+out_free:
+	kfree(priv);
+
+out_clear:
 	clear_bit(0, &chip->is_open);
-	return -ENOMEM;
+
+	return rc;
 }
 
 /*
@@ -68,5 +75,6 @@  const struct file_operations tpm_fops = {
 	.open = tpm_open,
 	.read = tpm_common_read,
 	.write = tpm_common_write,
+	.poll = tpm_common_poll,
 	.release = tpm_release,
 };
diff --git a/drivers/char/tpm/tpm-dev.h b/drivers/char/tpm/tpm-dev.h
index 4048677bbd78..2f0aeff57002 100644
--- a/drivers/char/tpm/tpm-dev.h
+++ b/drivers/char/tpm/tpm-dev.h
@@ -2,28 +2,33 @@ 
 #ifndef _TPM_DEV_H
 #define _TPM_DEV_H
 
+#include <linux/poll.h>
 #include "tpm.h"
 
 struct file_priv {
 	struct tpm_chip *chip;
 	struct tpm_space *space;
 
-	/* Data passed to and from the tpm via the read/write calls */
-	size_t data_pending;
+	/* Holds the amount of data passed or an error code from async op */
+	ssize_t data_pending;
 	struct mutex buffer_mutex;
 
 	struct timer_list user_read_timer;      /* user needs to claim result */
-	struct work_struct work;
+	struct work_struct timeout_work;
+	struct work_struct async_work;
+	wait_queue_head_t async_wait;
+	bool command_enqueued;
 
 	u8 data_buffer[TPM_BUFSIZE];
 };
 
-void tpm_common_open(struct file *file, struct tpm_chip *chip,
-		     struct file_priv *priv, struct tpm_space *space);
+int tpm_common_open(struct file *file, struct tpm_chip *chip,
+		    struct file_priv *priv, struct tpm_space *space);
 ssize_t tpm_common_read(struct file *file, char __user *buf,
 			size_t size, loff_t *off);
 ssize_t tpm_common_write(struct file *file, const char __user *buf,
 			 size_t size, loff_t *off);
-void tpm_common_release(struct file *file, struct file_priv *priv);
+__poll_t tpm_common_poll(struct file *file, poll_table *wait);
 
+void tpm_common_release(struct file *file, struct file_priv *priv);
 #endif
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 1a803b0cf980..9e3de6447512 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -1428,6 +1428,7 @@  static void __exit tpm_exit(void)
 	class_destroy(tpm_class);
 	class_destroy(tpmrm_class);
 	unregister_chrdev_region(tpm_devt, 2*TPM_NUM_DEVICES);
+	tpm_dev_common_exit();
 }
 
 subsys_initcall(tpm_init);
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index f3501d05264f..b909dc9e251f 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -604,4 +604,5 @@  int tpm2_commit_space(struct tpm_chip *chip, struct tpm_space *space,
 
 int tpm_bios_log_setup(struct tpm_chip *chip);
 void tpm_bios_log_teardown(struct tpm_chip *chip);
+void tpm_dev_common_exit(void);
 #endif
diff --git a/drivers/char/tpm/tpmrm-dev.c b/drivers/char/tpm/tpmrm-dev.c
index 96006c6b9696..f131c97c1577 100644
--- a/drivers/char/tpm/tpmrm-dev.c
+++ b/drivers/char/tpm/tpmrm-dev.c
@@ -23,14 +23,22 @@  static int tpmrm_open(struct inode *inode, struct file *file)
 		return -ENOMEM;
 
 	rc = tpm2_init_space(&priv->space);
-	if (rc) {
-		kfree(priv);
-		return -ENOMEM;
-	}
+	if (rc)
+		goto out_free;
 
-	tpm_common_open(file, chip, &priv->priv, &priv->space);
+	rc = tpm_common_open(file, chip, &priv->priv, &priv->space);
+	if (rc)
+		goto out_del_space;
 
 	return 0;
+
+out_del_space:
+	tpm2_del_space(chip, &priv->space);
+
+out_free:
+	kfree(priv);
+
+	return rc;
 }
 
 static int tpmrm_release(struct inode *inode, struct file *file)
@@ -51,5 +59,6 @@  const struct file_operations tpmrm_fops = {
 	.open = tpmrm_open,
 	.read = tpm_common_read,
 	.write = tpm_common_write,
+	.poll = tpm_common_poll,
 	.release = tpmrm_release,
 };