diff mbox

[1/2] soc: qcom: smsm: Handle probe deferral

Message ID 20170315114357.14446-1-j.neuschaefer@gmx.net (mailing list archive)
State Rejected, archived
Delegated to: Andy Gross
Headers show

Commit Message

J. Neuschäfer March 15, 2017, 11:43 a.m. UTC
If qcom_smem_get or qcom_smem_alloc return -EPROBE_DEFER, let the caller
the caller handle it, instead of treating it as an error.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>

---
v1:
- TODO: Reading qcom_smsm_probe, I noticed memory leaks in error paths:
  smsm, smsm->entries, etc. are allocated (with devm_kzalloc), but not
  freed when the function returns early. This should be addressed at
  some point (in a separate patch).
---
 drivers/soc/qcom/smsm.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

Comments

J. Neuschäfer March 17, 2017, 2:01 p.m. UTC | #1
On Wed, Mar 15, 2017 at 12:43:56PM +0100, Jonathan Neuschäfer wrote:
[...]
> - TODO: Reading qcom_smsm_probe, I noticed memory leaks in error paths:
>   smsm, smsm->entries, etc. are allocated (with devm_kzalloc), but not
>   freed when the function returns early. This should be addressed at
>   some point (in a separate patch).

This is not actually true (see Documentation/driver-model/devres.txt).
Sorry for the noise.


Jonathan Neuschäfer
Bjorn Andersson March 28, 2017, 6:18 a.m. UTC | #2
On Wed 15 Mar 04:43 PDT 2017, Jonathan Neusch?fer wrote:

> If qcom_smem_get or qcom_smem_alloc return -EPROBE_DEFER, let the caller
> the caller handle it, instead of treating it as an error.
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> 
> ---
> v1:
> - TODO: Reading qcom_smsm_probe, I noticed memory leaks in error paths:
>   smsm, smsm->entries, etc. are allocated (with devm_kzalloc), but not
>   freed when the function returns early. This should be addressed at
>   some point (in a separate patch).
> ---
>  drivers/soc/qcom/smsm.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
> index d0337b2a71c8..3918645e5708 100644
> --- a/drivers/soc/qcom/smsm.c
> +++ b/drivers/soc/qcom/smsm.c
> @@ -439,7 +439,9 @@ static int smsm_get_size_info(struct qcom_smsm *smsm)
>  	} *info;
>  
>  	info = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SIZE_INFO, &size);
> -	if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {
> +	if (PTR_ERR(info) == -EPROBE_DEFER) {
> +		return PTR_ERR(info);
> +	} else if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {

The following elseif was supposed to take care of this case, but I
clearly screwed this up.

Rather than adding a special case for EPROBE_DEFER before the two checks
and then fix up the original expression to make errors fall back to the
original else, I think you should rearrange the conditionals.

Probably better to write it like this instead:

        if (IS_ERR(info) && PTR_ERR(info) != -ENOENT) {
                if (PTR_ERR(info) != -EPROBE_DEFER)
                        dev_err(smsm->dev, "unable to retrieve smsm size info\n");
                return PTR_ERR(info);
        } else if (IS_ERR(info) || size != sizeof(*info)) {
                dev_warn(smsm->dev, "no smsm size info, using defaults\n");
                smsm->num_entries = SMSM_DEFAULT_NUM_ENTRIES;
                smsm->num_hosts = SMSM_DEFAULT_NUM_HOSTS;
                return 0;
        }

>  		dev_warn(smsm->dev, "no smsm size info, using defaults\n");
>  		smsm->num_entries = SMSM_DEFAULT_NUM_ENTRIES;
>  		smsm->num_hosts = SMSM_DEFAULT_NUM_HOSTS;
> @@ -515,7 +517,9 @@ static int qcom_smsm_probe(struct platform_device *pdev)
>  	/* Acquire the main SMSM state vector */
>  	ret = qcom_smem_alloc(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SHARED_STATE,
>  			      smsm->num_entries * sizeof(u32));
> -	if (ret < 0 && ret != -EEXIST) {
> +	if (ret == -EPROBE_DEFER) {
> +		return ret;
> +	} else if (ret < 0 && ret != -EEXIST) {

The idiomatic way to write this is:

if (ret < 0 && ret != -EEXIST) {
	if (ret != -EPROBE_DEFER)
		dev_err();
	return ret;
}

However, for us to reach this point in smsm_probe() the above
qcom_smem_get() must have returned successfully, i.e. we have SMEM in
place so there's no need to handle this case specifically.

>  		dev_err(&pdev->dev, "unable to allocate shared state entry\n");
>  		return ret;
>  	}

Regards,
Bjorn
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J. Neuschäfer April 4, 2017, 2:38 a.m. UTC | #3
On Mon, Mar 27, 2017 at 11:18:29PM -0700, Bjorn Andersson wrote:
> On Wed 15 Mar 04:43 PDT 2017, Jonathan Neusch?fer wrote:
[...]
> >  	info = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SIZE_INFO, &size);
> > -	if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {
> > +	if (PTR_ERR(info) == -EPROBE_DEFER) {
> > +		return PTR_ERR(info);
> > +	} else if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {
> 
> The following elseif was supposed to take care of this case, but I
> clearly screwed this up.
> 
> Rather than adding a special case for EPROBE_DEFER before the two checks
> and then fix up the original expression to make errors fall back to the
> original else, I think you should rearrange the conditionals.
> 
> Probably better to write it like this instead:
> 
>         if (IS_ERR(info) && PTR_ERR(info) != -ENOENT) {
>                 if (PTR_ERR(info) != -EPROBE_DEFER)
>                         dev_err(smsm->dev, "unable to retrieve smsm size info\n");
>                 return PTR_ERR(info);
>         } else if (IS_ERR(info) || size != sizeof(*info)) {
>                 dev_warn(smsm->dev, "no smsm size info, using defaults\n");
>                 smsm->num_entries = SMSM_DEFAULT_NUM_ENTRIES;
>                 smsm->num_hosts = SMSM_DEFAULT_NUM_HOSTS;
>                 return 0;
>         }

Indeed, this looks better.

And it also obsoletes my patch 2/2, which is nice.

> >  		dev_warn(smsm->dev, "no smsm size info, using defaults\n");
> >  		smsm->num_entries = SMSM_DEFAULT_NUM_ENTRIES;
> >  		smsm->num_hosts = SMSM_DEFAULT_NUM_HOSTS;
> > @@ -515,7 +517,9 @@ static int qcom_smsm_probe(struct platform_device *pdev)
> >  	/* Acquire the main SMSM state vector */
> >  	ret = qcom_smem_alloc(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SHARED_STATE,
> >  			      smsm->num_entries * sizeof(u32));
> > -	if (ret < 0 && ret != -EEXIST) {
> > +	if (ret == -EPROBE_DEFER) {
> > +		return ret;
> > +	} else if (ret < 0 && ret != -EEXIST) {
> 
> The idiomatic way to write this is:
> 
> if (ret < 0 && ret != -EEXIST) {
> 	if (ret != -EPROBE_DEFER)
> 		dev_err();
> 	return ret;
> }
> 
> However, for us to reach this point in smsm_probe() the above
> qcom_smem_get() must have returned successfully, i.e. we have SMEM in
> place so there's no need to handle this case specifically.

I came to the same conclusion but wasn't sure. I'll drop this part from
my patch.

I'll send a v2 of this series, although after applying your suggestions,
I can't claim much originality anymore.


Thanks for the review,
Jonathan Neuschäfer
Bjorn Andersson April 5, 2017, 3:47 a.m. UTC | #4
On Mon 03 Apr 19:38 PDT 2017, Jonathan Neusch?fer wrote:

> On Mon, Mar 27, 2017 at 11:18:29PM -0700, Bjorn Andersson wrote:
[..]
> > However, for us to reach this point in smsm_probe() the above
> > qcom_smem_get() must have returned successfully, i.e. we have SMEM in
> > place so there's no need to handle this case specifically.
> 
> I came to the same conclusion but wasn't sure. I'll drop this part from
> my patch.
> 
> I'll send a v2 of this series, although after applying your suggestions,
> I can't claim much originality anymore.
> 

Don't worry about it. Looking forward to version 2.

Regards,
Bjorn
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diff mbox

Patch

diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
index d0337b2a71c8..3918645e5708 100644
--- a/drivers/soc/qcom/smsm.c
+++ b/drivers/soc/qcom/smsm.c
@@ -439,7 +439,9 @@  static int smsm_get_size_info(struct qcom_smsm *smsm)
 	} *info;
 
 	info = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SIZE_INFO, &size);
-	if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {
+	if (PTR_ERR(info) == -EPROBE_DEFER) {
+		return PTR_ERR(info);
+	} else if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {
 		dev_warn(smsm->dev, "no smsm size info, using defaults\n");
 		smsm->num_entries = SMSM_DEFAULT_NUM_ENTRIES;
 		smsm->num_hosts = SMSM_DEFAULT_NUM_HOSTS;
@@ -515,7 +517,9 @@  static int qcom_smsm_probe(struct platform_device *pdev)
 	/* Acquire the main SMSM state vector */
 	ret = qcom_smem_alloc(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SHARED_STATE,
 			      smsm->num_entries * sizeof(u32));
-	if (ret < 0 && ret != -EEXIST) {
+	if (ret == -EPROBE_DEFER) {
+		return ret;
+	} else if (ret < 0 && ret != -EEXIST) {
 		dev_err(&pdev->dev, "unable to allocate shared state entry\n");
 		return ret;
 	}