2018-07-12 21:56:55

by Tuomas Tynkkynen

Subject: [PATCH 1/2] staging: bcm2835-audio: Check if workqueue allocation failed

Currently, if allocating a workqueue fails, the driver will probe
successfully but it will silently do nothing, which is rather silly.
So instead bail out with -ENOMEM in bcm2835_audio_open() if
alloc_workqueue() fails, and remove the now pointless checks for a NULL
workqueue.

While at it, get rid of the rather pointless one-line function
my_workqueue_init().

Signed-off-by: Tuomas Tynkkynen <[email protected]>
---
.../vc04_services/bcm2835-audio/bcm2835-vchiq.c | 111 ++++++++++-----------
1 file changed, 50 insertions(+), 61 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
index a4a48f31f1a3..85ed807bb873 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
@@ -118,44 +118,40 @@ static void my_wq_function(struct work_struct *work)

int bcm2835_audio_start(struct bcm2835_alsa_stream *alsa_stream)
{
- if (alsa_stream->my_wq) {
- struct bcm2835_audio_work *work;
-
- work = kmalloc(sizeof(*work), GFP_ATOMIC);
- /*--- Queue some work (item 1) ---*/
- if (!work) {
- LOG_ERR(" .. Error: NULL work kmalloc\n");
- return -ENOMEM;
- }
- INIT_WORK(&work->my_work, my_wq_function);
- work->alsa_stream = alsa_stream;
- work->cmd = BCM2835_AUDIO_START;
- if (!queue_work(alsa_stream->my_wq, &work->my_work)) {
- kfree(work);
- return -EBUSY;
- }
+ struct bcm2835_audio_work *work;
+
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ /*--- Queue some work (item 1) ---*/
+ if (!work) {
+ LOG_ERR(" .. Error: NULL work kmalloc\n");
+ return -ENOMEM;
+ }
+ INIT_WORK(&work->my_work, my_wq_function);
+ work->alsa_stream = alsa_stream;
+ work->cmd = BCM2835_AUDIO_START;
+ if (!queue_work(alsa_stream->my_wq, &work->my_work)) {
+ kfree(work);
+ return -EBUSY;
}
return 0;
}

int bcm2835_audio_stop(struct bcm2835_alsa_stream *alsa_stream)
{
- if (alsa_stream->my_wq) {
- struct bcm2835_audio_work *work;
-
- work = kmalloc(sizeof(*work), GFP_ATOMIC);
- /*--- Queue some work (item 1) ---*/
- if (!work) {
- LOG_ERR(" .. Error: NULL work kmalloc\n");
- return -ENOMEM;
- }
- INIT_WORK(&work->my_work, my_wq_function);
- work->alsa_stream = alsa_stream;
- work->cmd = BCM2835_AUDIO_STOP;
- if (!queue_work(alsa_stream->my_wq, &work->my_work)) {
- kfree(work);
- return -EBUSY;
- }
+ struct bcm2835_audio_work *work;
+
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ /*--- Queue some work (item 1) ---*/
+ if (!work) {
+ LOG_ERR(" .. Error: NULL work kmalloc\n");
+ return -ENOMEM;
+ }
+ INIT_WORK(&work->my_work, my_wq_function);
+ work->alsa_stream = alsa_stream;
+ work->cmd = BCM2835_AUDIO_STOP;
+ if (!queue_work(alsa_stream->my_wq, &work->my_work)) {
+ kfree(work);
+ return -EBUSY;
}
return 0;
}
@@ -163,40 +159,31 @@ int bcm2835_audio_stop(struct bcm2835_alsa_stream *alsa_stream)
int bcm2835_audio_write(struct bcm2835_alsa_stream *alsa_stream,
unsigned int count, void *src)
{
- if (alsa_stream->my_wq) {
- struct bcm2835_audio_work *work;
-
- work = kmalloc(sizeof(*work), GFP_ATOMIC);
- /*--- Queue some work (item 1) ---*/
- if (!work) {
- LOG_ERR(" .. Error: NULL work kmalloc\n");
- return -ENOMEM;
- }
- INIT_WORK(&work->my_work, my_wq_function);
- work->alsa_stream = alsa_stream;
- work->cmd = BCM2835_AUDIO_WRITE;
- work->src = src;
- work->count = count;
- if (!queue_work(alsa_stream->my_wq, &work->my_work)) {
- kfree(work);
- return -EBUSY;
- }
+ struct bcm2835_audio_work *work;
+
+ work = kmalloc(sizeof(*work), GFP_ATOMIC);
+ /*--- Queue some work (item 1) ---*/
+ if (!work) {
+ LOG_ERR(" .. Error: NULL work kmalloc\n");
+ return -ENOMEM;
+ }
+ INIT_WORK(&work->my_work, my_wq_function);
+ work->alsa_stream = alsa_stream;
+ work->cmd = BCM2835_AUDIO_WRITE;
+ work->src = src;
+ work->count = count;
+ if (!queue_work(alsa_stream->my_wq, &work->my_work)) {
+ kfree(work);
+ return -EBUSY;
}
return 0;
}

-static void my_workqueue_init(struct bcm2835_alsa_stream *alsa_stream)
-{
- alsa_stream->my_wq = alloc_workqueue("my_queue", WQ_HIGHPRI, 1);
-}
-
static void my_workqueue_quit(struct bcm2835_alsa_stream *alsa_stream)
{
- if (alsa_stream->my_wq) {
- flush_workqueue(alsa_stream->my_wq);
- destroy_workqueue(alsa_stream->my_wq);
- alsa_stream->my_wq = NULL;
- }
+ flush_workqueue(alsa_stream->my_wq);
+ destroy_workqueue(alsa_stream->my_wq);
+ alsa_stream->my_wq = NULL;
}

static void audio_vchi_callback(void *param,
@@ -424,7 +411,9 @@ int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream)
int status;
int ret;

- my_workqueue_init(alsa_stream);
+ alsa_stream->my_wq = alloc_workqueue("my_queue", WQ_HIGHPRI, 1);
+ if (!alsa_stream->my_wq)
+ return -ENOMEM;

ret = bcm2835_audio_open_connection(alsa_stream);
if (ret) {
--
2.16.3

2018-07-12 21:56:36

by Tuomas Tynkkynen

Subject: [PATCH 2/2] staging: bcm2835-audio: Don't leak workqueue if open fails

Currently, if bcm2835_audio_open() fails partway, the allocated
workqueue is leaked. Avoid that.

While at it, propagate the return value of
bcm2835_audio_open_connection() on failure instead of returning -1.

Signed-off-by: Tuomas Tynkkynen <[email protected]>
---
.../staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
index 85ed807bb873..779c1e993b55 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-vchiq.c
@@ -416,16 +416,16 @@ int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream)
return -ENOMEM;

ret = bcm2835_audio_open_connection(alsa_stream);
- if (ret) {
- ret = -1;
- goto exit;
- }
+ if (ret)
+ goto free_wq;
+
instance = alsa_stream->instance;
LOG_DBG(" instance (%p)\n", instance);

if (mutex_lock_interruptible(&instance->vchi_mutex)) {
LOG_DBG("Interrupted whilst waiting for lock on (%d)\n", instance->num_connections);
- return -EINTR;
+ ret = -EINTR;
+ goto free_wq;
}
vchi_service_use(instance->vchi_handle[0]);

@@ -448,7 +448,11 @@ int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream)
unlock:
vchi_service_release(instance->vchi_handle[0]);
mutex_unlock(&instance->vchi_mutex);
-exit:
+
+free_wq:
+ if (ret)
+ destroy_workqueue(alsa_stream->my_wq);
+
return ret;
}

--
2.16.3

2018-07-13 06:50:36

by Dan Carpenter

Subject: Re: [PATCH 1/2] staging: bcm2835-audio: Check if workqueue allocation failed

On Fri, Jul 13, 2018 at 12:54:16AM +0300, Tuomas Tynkkynen wrote:
> @@ -424,7 +411,9 @@ int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream)
> int status;
> int ret;
>
> - my_workqueue_init(alsa_stream);
> + alsa_stream->my_wq = alloc_workqueue("my_queue", WQ_HIGHPRI, 1);
> + if (!alsa_stream->my_wq)
> + return -ENOMEM;
>
> ret = bcm2835_audio_open_connection(alsa_stream);
> if (ret) {

This patch is good but if bcm2835_audio_open_connection() fails then
we need to release alsa_stream->my_wq.

regards,
dan carpenter

2018-07-13 06:59:02

by Dan Carpenter

Subject: Re: [PATCH 1/2] staging: bcm2835-audio: Check if workqueue allocation failed

On Fri, Jul 13, 2018 at 09:48:16AM +0300, Dan Carpenter wrote:
> On Fri, Jul 13, 2018 at 12:54:16AM +0300, Tuomas Tynkkynen wrote:
> > @@ -424,7 +411,9 @@ int bcm2835_audio_open(struct bcm2835_alsa_stream *alsa_stream)
> > int status;
> > int ret;
> >
> > - my_workqueue_init(alsa_stream);
> > + alsa_stream->my_wq = alloc_workqueue("my_queue", WQ_HIGHPRI, 1);
> > + if (!alsa_stream->my_wq)
> > + return -ENOMEM;
> >
> > ret = bcm2835_audio_open_connection(alsa_stream);
> > if (ret) {
>
> This patch is good but if bcm2835_audio_open_connection() fails then
> we need to release alsa_stream->my_wq.

Never mind, you handle it in the next patch. The bug *was* there in the
original code as well, so that's a legit way to split the patches.

regards,
dan carpenter