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Groups > linux.kernel > #1601333 > unrolled thread

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

Started byJonathan Neuschäfer <j.neuschaefer@gmx.net>
First post2017-03-15 12:50 +0100
Last post2017-04-05 19:10 +0200
Articles 8 — 2 participants

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  [PATCH 1/2] soc: qcom: smsm: Handle probe deferral Jonathan Neuschäfer <j.neuschaefer@gmx.net> - 2017-03-15 12:50 +0100
    [PATCH 2/2] soc: qcom: smsm: Avoid the use of an uninitialized value Jonathan Neuschäfer <j.neuschaefer@gmx.net> - 2017-03-15 12:50 +0100
    Re: [PATCH 1/2] soc: qcom: smsm: Handle probe deferral Jonathan Neuschäfer <j.neuschaefer@gmx.net> - 2017-03-17 15:10 +0100
    Re: [PATCH 1/2] soc: qcom: smsm: Handle probe deferral Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-03-28 08:20 +0200
      Re: [PATCH 1/2] soc: qcom: smsm: Handle probe deferral Jonathan Neuschäfer <j.neuschaefer@gmx.net> - 2017-04-04 04:40 +0200
        Re: [PATCH 1/2] soc: qcom: smsm: Handle probe deferral Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-04-05 05:50 +0200
        [PATCH v2] soc: qcom: smsm: Improve error handling, quiesce probe deferral Jonathan Neuschäfer <j.neuschaefer@gmx.net> - 2017-04-05 14:20 +0200
          Re: [PATCH v2] soc: qcom: smsm: Improve error handling, quiesce  probe deferral Bjorn Andersson <bjorn.andersson@linaro.org> - 2017-04-05 19:10 +0200

#1601333 — [PATCH 1/2] soc: qcom: smsm: Handle probe deferral

FromJonathan Neuschäfer <j.neuschaefer@gmx.net>
Date2017-03-15 12:50 +0100
Subject[PATCH 1/2] soc: qcom: smsm: Handle probe deferral
Message-ID<tlfBg-73v-13@gated-at.bofh.it>
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)) {
 		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;
 	}
-- 
2.11.0

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#1601337 — [PATCH 2/2] soc: qcom: smsm: Avoid the use of an uninitialized value

FromJonathan Neuschäfer <j.neuschaefer@gmx.net>
Date2017-03-15 12:50 +0100
Subject[PATCH 2/2] soc: qcom: smsm: Avoid the use of an uninitialized value
Message-ID<tlfBg-73v-27@gated-at.bofh.it>
In reply to#1601333
If qcom_smem_get returns an error besides -EPROBE_DEFER or -ENOENT,
don't assume that size has been set.

Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
---
 drivers/soc/qcom/smsm.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
index 3918645e5708..632c060c9cc0 100644
--- a/drivers/soc/qcom/smsm.c
+++ b/drivers/soc/qcom/smsm.c
@@ -441,7 +441,8 @@ static int smsm_get_size_info(struct qcom_smsm *smsm)
 	info = qcom_smem_get(QCOM_SMEM_HOST_ANY, SMEM_SMSM_SIZE_INFO, &size);
 	if (PTR_ERR(info) == -EPROBE_DEFER) {
 		return PTR_ERR(info);
-	} else if (PTR_ERR(info) == -ENOENT || size != sizeof(*info)) {
+	} else if (PTR_ERR(info) == -ENOENT ||
+			(!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;
-- 
2.11.0

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#1603345

FromJonathan Neuschäfer <j.neuschaefer@gmx.net>
Date2017-03-17 15:10 +0100
Message-ID<tm0JQ-7zo-23@gated-at.bofh.it>
In reply to#1601333

[Multipart message — attachments visible in raw view] — view raw

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

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#1610354

FromBjorn Andersson <bjorn.andersson@linaro.org>
Date2017-03-28 08:20 +0200
Message-ID<tpSE1-3sW-9@gated-at.bofh.it>
In reply to#1601333
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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#1615662

FromJonathan Neuschäfer <j.neuschaefer@gmx.net>
Date2017-04-04 04:40 +0200
Message-ID<tsmxX-76q-1@gated-at.bofh.it>
In reply to#1610354

[Multipart message — attachments visible in raw view] — view raw

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

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#1616550

FromBjorn Andersson <bjorn.andersson@linaro.org>
Date2017-04-05 05:50 +0200
Message-ID<tsK7f-5H7-13@gated-at.bofh.it>
In reply to#1615662
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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#1616880 — [PATCH v2] soc: qcom: smsm: Improve error handling, quiesce probe deferral

FromJonathan Neuschäfer <j.neuschaefer@gmx.net>
Date2017-04-05 14:20 +0200
Subject[PATCH v2] soc: qcom: smsm: Improve error handling, quiesce probe deferral
Message-ID<tsS4O-2vv-5@gated-at.bofh.it>
In reply to#1615662
Don't use size if info indicates an error condition. Previously a
non-ENOENT error (such as -EPROBE_DEFER) would lead to size being used
even though it hadn't necessarily been initialized in qcom_smem_get.

Don't print an error message in the -EPROBE_DEFER case.

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

---
v2:
- Rewrite based on Bjorn's suggestion.
- Don't check for -EPROBE_DEFER again after qcom_smem_alloc was called
  in qcom_smsm_probe. This point is only reached if smsm_get_size_info
  returned success, which can only happen if probe deferral is over.
v1:
- was "[PATCH 1/2] soc: qcom: smsm: Handle probe deferral"
---
 drivers/soc/qcom/smsm.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
index d0337b2a71c8..dc540ea92e9d 100644
--- a/drivers/soc/qcom/smsm.c
+++ b/drivers/soc/qcom/smsm.c
@@ -439,14 +439,15 @@ 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 (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;
-	} else if (IS_ERR(info)) {
-		dev_err(smsm->dev, "unable to retrieve smsm size info\n");
-		return PTR_ERR(info);
 	}
 
 	smsm->num_entries = info->num_entries;
-- 
2.11.0

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#1617158 — Re: [PATCH v2] soc: qcom: smsm: Improve error handling, quiesce probe deferral

FromBjorn Andersson <bjorn.andersson@linaro.org>
Date2017-04-05 19:10 +0200
SubjectRe: [PATCH v2] soc: qcom: smsm: Improve error handling, quiesce probe deferral
Message-ID<tsWBt-5sA-61@gated-at.bofh.it>
In reply to#1616880
On Wed 05 Apr 05:10 PDT 2017, Jonathan Neusch?fer wrote:

> Don't use size if info indicates an error condition. Previously a
> non-ENOENT error (such as -EPROBE_DEFER) would lead to size being used
> even though it hadn't necessarily been initialized in qcom_smem_get.
> 
> Don't print an error message in the -EPROBE_DEFER case.
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> 
> ---
> v2:
> - Rewrite based on Bjorn's suggestion.
> - Don't check for -EPROBE_DEFER again after qcom_smem_alloc was called
>   in qcom_smsm_probe. This point is only reached if smsm_get_size_info
>   returned success, which can only happen if probe deferral is over.
> v1:
> - was "[PATCH 1/2] soc: qcom: smsm: Handle probe deferral"
> ---
>  drivers/soc/qcom/smsm.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/soc/qcom/smsm.c b/drivers/soc/qcom/smsm.c
> index d0337b2a71c8..dc540ea92e9d 100644
> --- a/drivers/soc/qcom/smsm.c
> +++ b/drivers/soc/qcom/smsm.c
> @@ -439,14 +439,15 @@ 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 (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;
> -	} else if (IS_ERR(info)) {
> -		dev_err(smsm->dev, "unable to retrieve smsm size info\n");
> -		return PTR_ERR(info);
>  	}
>  
>  	smsm->num_entries = info->num_entries;
> -- 
> 2.11.0
>

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