2019-11-07 01:46:21

by Daniel Almeida

Subject: [PATCH] media: dvb_dummy_fe: Add error messages in case of attach failure

From: "Daniel W. S. Almeida" <[email protected]>

Complain if the attach functions fail, for any reason. This is helpful
when debugging.

Suggested-by: Shuah Khan <[email protected]>
Signed-off-by: Daniel W. S. Almeida <[email protected]>
---
drivers/media/dvb-frontends/dvb_dummy_fe.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/media/dvb-frontends/dvb_dummy_fe.c b/drivers/media/dvb-frontends/dvb_dummy_fe.c
index 4db679cb70ad..ca86857c3667 100644
--- a/drivers/media/dvb-frontends/dvb_dummy_fe.c
+++ b/drivers/media/dvb-frontends/dvb_dummy_fe.c
@@ -114,12 +114,16 @@ struct dvb_frontend* dvb_dummy_fe_ofdm_attach(void)
/* allocate memory for the internal state */
state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
if (!state)
- return NULL;
+ goto err;

/* create dvb_frontend */
memcpy(&state->frontend.ops, &dvb_dummy_fe_ofdm_ops, sizeof(struct dvb_frontend_ops));
state->frontend.demodulator_priv = state;
return &state->frontend;
+
+err:
+ pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
+ return NULL;
}

static const struct dvb_frontend_ops dvb_dummy_fe_qpsk_ops;
@@ -131,12 +135,16 @@ struct dvb_frontend *dvb_dummy_fe_qpsk_attach(void)
/* allocate memory for the internal state */
state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
if (!state)
- return NULL;
+ goto err;

/* create dvb_frontend */
memcpy(&state->frontend.ops, &dvb_dummy_fe_qpsk_ops, sizeof(struct dvb_frontend_ops));
state->frontend.demodulator_priv = state;
return &state->frontend;
+
+err:
+ pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
+ return NULL;
}

static const struct dvb_frontend_ops dvb_dummy_fe_qam_ops;
@@ -148,12 +156,16 @@ struct dvb_frontend *dvb_dummy_fe_qam_attach(void)
/* allocate memory for the internal state */
state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
if (!state)
- return NULL;
+ goto err;

/* create dvb_frontend */
memcpy(&state->frontend.ops, &dvb_dummy_fe_qam_ops, sizeof(struct dvb_frontend_ops));
state->frontend.demodulator_priv = state;
return &state->frontend;
+
+err:
+ pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
+ return NULL;
}

static const struct dvb_frontend_ops dvb_dummy_fe_ofdm_ops = {
--
2.24.0

2019-11-30 06:56:50

by Mauro Carvalho Chehab

Subject: Re: [PATCH] media: dvb_dummy_fe: Add error messages in case of attach failure

Em Wed, 6 Nov 2019 22:37:45 -0300
"Daniel W. S. Almeida" <[email protected]> escreveu:

> From: "Daniel W. S. Almeida" <[email protected]>
>
> Complain if the attach functions fail, for any reason. This is helpful
> when debugging.
>
> Suggested-by: Shuah Khan <[email protected]>
> Signed-off-by: Daniel W. S. Almeida <[email protected]>

Looks OK to me.

> ---
> drivers/media/dvb-frontends/dvb_dummy_fe.c | 18 +++++++++++++++---
> 1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/media/dvb-frontends/dvb_dummy_fe.c b/drivers/media/dvb-frontends/dvb_dummy_fe.c
> index 4db679cb70ad..ca86857c3667 100644
> --- a/drivers/media/dvb-frontends/dvb_dummy_fe.c
> +++ b/drivers/media/dvb-frontends/dvb_dummy_fe.c
> @@ -114,12 +114,16 @@ struct dvb_frontend* dvb_dummy_fe_ofdm_attach(void)
> /* allocate memory for the internal state */
> state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
> if (!state)
> - return NULL;
> + goto err;
>
> /* create dvb_frontend */
> memcpy(&state->frontend.ops, &dvb_dummy_fe_ofdm_ops, sizeof(struct dvb_frontend_ops));
> state->frontend.demodulator_priv = state;
> return &state->frontend;
> +
> +err:
> + pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
> + return NULL;
> }
>
> static const struct dvb_frontend_ops dvb_dummy_fe_qpsk_ops;
> @@ -131,12 +135,16 @@ struct dvb_frontend *dvb_dummy_fe_qpsk_attach(void)
> /* allocate memory for the internal state */
> state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
> if (!state)
> - return NULL;
> + goto err;
>
> /* create dvb_frontend */
> memcpy(&state->frontend.ops, &dvb_dummy_fe_qpsk_ops, sizeof(struct dvb_frontend_ops));
> state->frontend.demodulator_priv = state;
> return &state->frontend;
> +
> +err:
> + pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
> + return NULL;
> }
>
> static const struct dvb_frontend_ops dvb_dummy_fe_qam_ops;
> @@ -148,12 +156,16 @@ struct dvb_frontend *dvb_dummy_fe_qam_attach(void)
> /* allocate memory for the internal state */
> state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
> if (!state)
> - return NULL;
> + goto err;
>
> /* create dvb_frontend */
> memcpy(&state->frontend.ops, &dvb_dummy_fe_qam_ops, sizeof(struct dvb_frontend_ops));
> state->frontend.demodulator_priv = state;
> return &state->frontend;
> +
> +err:
> + pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
> + return NULL;
> }
>
> static const struct dvb_frontend_ops dvb_dummy_fe_ofdm_ops = {



Cheers,
Mauro

2019-12-31 09:48:00

by Sean Young

Subject: Re: [PATCH] media: dvb_dummy_fe: Add error messages in case of attach failure

Hi Daniel, Mauro,

On Sat, Nov 30, 2019 at 07:54:15AM +0100, Mauro Carvalho Chehab wrote:
> Em Wed, 6 Nov 2019 22:37:45 -0300
> "Daniel W. S. Almeida" <[email protected]> escreveu:
>
> > From: "Daniel W. S. Almeida" <[email protected]>
> >
> > Complain if the attach functions fail, for any reason. This is helpful
> > when debugging.
> >
> > Suggested-by: Shuah Khan <[email protected]>
> > Signed-off-by: Daniel W. S. Almeida <[email protected]>
>
> Looks OK to me.
>
> > ---
> > drivers/media/dvb-frontends/dvb_dummy_fe.c | 18 +++++++++++++++---
> > 1 file changed, 15 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/media/dvb-frontends/dvb_dummy_fe.c b/drivers/media/dvb-frontends/dvb_dummy_fe.c
> > index 4db679cb70ad..ca86857c3667 100644
> > --- a/drivers/media/dvb-frontends/dvb_dummy_fe.c
> > +++ b/drivers/media/dvb-frontends/dvb_dummy_fe.c
> > @@ -114,12 +114,16 @@ struct dvb_frontend* dvb_dummy_fe_ofdm_attach(void)
> > /* allocate memory for the internal state */
> > state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
> > if (!state)
> > - return NULL;
> > + goto err;
> >
> > /* create dvb_frontend */
> > memcpy(&state->frontend.ops, &dvb_dummy_fe_ofdm_ops, sizeof(struct dvb_frontend_ops));
> > state->frontend.demodulator_priv = state;
> > return &state->frontend;
> > +
> > +err:
> > + pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
> > + return NULL;
> > }

If kzalloc() fails, it will already complain before returning. Lately we've
been removing error logs after kmalloc() failures. I'm sure someone will send
in patches reverting this if it gets merged.

Is this a good idea?

Sean

> >
> > static const struct dvb_frontend_ops dvb_dummy_fe_qpsk_ops;
> > @@ -131,12 +135,16 @@ struct dvb_frontend *dvb_dummy_fe_qpsk_attach(void)
> > /* allocate memory for the internal state */
> > state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
> > if (!state)
> > - return NULL;
> > + goto err;
> >
> > /* create dvb_frontend */
> > memcpy(&state->frontend.ops, &dvb_dummy_fe_qpsk_ops, sizeof(struct dvb_frontend_ops));
> > state->frontend.demodulator_priv = state;
> > return &state->frontend;
> > +
> > +err:
> > + pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
> > + return NULL;
> > }
> >
> > static const struct dvb_frontend_ops dvb_dummy_fe_qam_ops;
> > @@ -148,12 +156,16 @@ struct dvb_frontend *dvb_dummy_fe_qam_attach(void)
> > /* allocate memory for the internal state */
> > state = kzalloc(sizeof(struct dvb_dummy_fe_state), GFP_KERNEL);
> > if (!state)
> > - return NULL;
> > + goto err;
> >
> > /* create dvb_frontend */
> > memcpy(&state->frontend.ops, &dvb_dummy_fe_qam_ops, sizeof(struct dvb_frontend_ops));
> > state->frontend.demodulator_priv = state;
> > return &state->frontend;
> > +
> > +err:
> > + pr_err("%s: DVB Dummy frontend driver attach failed\n", __func__);
> > + return NULL;
> > }
> >
> > static const struct dvb_frontend_ops dvb_dummy_fe_ofdm_ops = {
>
>
>
> Cheers,
> Mauro