[PATCH v2 0/3] mmc: rectify boot param option for fault injection

[PATCH v2 0/3] mmc: rectify boot param option for fault injection

[Per Forlin]

Akinobu Mita reported that the boot option for mmc fault injection is never
compiled in due to a fauly "ifdef KERNEL" that is never set.
A correct ifdef would be "ifndef MODULE". This patch set adds a
module_param_cb() and thereby no ifndef MODULE is needed.
Using a module_param makes it possible to pass default fault attributes for
external modules too.

This patch set is for 3.2
Change log:
v2 - use module_param_cb() to set default fault attributes
   - fix spelling of documentation in patch #3  

Per Forlin (3):
  fault-inject: export setup_fault_attr()
  mmc: add module param to set fault injection attributes
  fault-injection: update documentation with the mmc module param

 Documentation/fault-injection/fault-injection.txt |    2 +-
 drivers/mmc/core/debugfs.c                        |   38 +++++++++++----------
 lib/fault-inject.c                                |    3 +-
 3 files changed, 23 insertions(+), 20 deletions(-)

-- 
1.7.4.1

[PATCH v2 1/3] fault-inject: export setup_fault_attr()

[Per Forlin]

mmc_core module needs to use setup_fault_attr() in order
to set fault injection attributes during module load time.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
---
 lib/fault-inject.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index 328d433..4f75540 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -14,7 +14,7 @@
  * setup_fault_attr() is a helper function for various __setup handlers, so it
  * returns 0 on error, because that is what __setup handlers do.
  */
-int __init setup_fault_attr(struct fault_attr *attr, char *str)
+int setup_fault_attr(struct fault_attr *attr, char *str)
 {
 	unsigned long probability;
 	unsigned long interval;
@@ -36,6 +36,7 @@ int __init setup_fault_attr(struct fault_attr *attr, char *str)
 
 	return 1;
 }
+EXPORT_SYMBOL_GPL(setup_fault_attr);
 
 static void fail_dump(struct fault_attr *attr)
 {
-- 
1.7.4.1

[PATCH v2 2/3] mmc: add module param to set fault injection attributes

[Per Forlin]

Replace setup("fail_mmc_request") and faulty "ifdef KERNEL" with
a module_param_cb(). The module param mmc_core.fail_request
may be used to set the fault injection attributes during boot time
or module load time.

Signed-off-by: Per Forlin <per.forlin@linaro.org>
---
 drivers/mmc/core/debugfs.c |   38 ++++++++++++++++++++------------------
 1 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index 5acd707..d80e234 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -20,6 +20,25 @@
 #include "core.h"
 #include "mmc_ops.h"
 
+#ifdef CONFIG_FAIL_MMC_REQUEST
+
+static DECLARE_FAULT_ATTR(fail_default_attr);
+static char *fail_request;
+static int fail_mmc_request_param_set(const char *val,
+				      const struct kernel_param *kp)
+{
+	setup_fault_attr(&fail_default_attr, (char *) val);
+	return 0;
+}
+
+static const struct kernel_param_ops fail_mmc_request_param_ops = {
+	.set = fail_mmc_request_param_set
+};
+module_param_cb(fail_request, &fail_mmc_request_param_ops,
+		&fail_request, 0);
+
+#endif /* CONFIG_FAIL_MMC_REQUEST */
+
 /* The debugfs functions are optimized away when CONFIG_DEBUG_FS isn't set. */
 static int mmc_ios_show(struct seq_file *s, void *data)
 {
@@ -159,23 +178,6 @@ static int mmc_clock_opt_set(void *data, u64 val)
 	return 0;
 }
 
-#ifdef CONFIG_FAIL_MMC_REQUEST
-
-static DECLARE_FAULT_ATTR(fail_mmc_request);
-
-#ifdef KERNEL
-/*
- * Internal function. Pass the boot param fail_mmc_request to
- * the setup fault injection attributes routine.
- */
-static int __init setup_fail_mmc_request(char *str)
-{
-	return setup_fault_attr(&fail_mmc_request, str);
-}
-__setup("fail_mmc_request=", setup_fail_mmc_request);
-#endif /* KERNEL */
-#endif /* CONFIG_FAIL_MMC_REQUEST */
-
 DEFINE_SIMPLE_ATTRIBUTE(mmc_clock_fops, mmc_clock_opt_get, mmc_clock_opt_set,
 	"%llu\n");
 
@@ -207,7 +209,7 @@ void mmc_add_host_debugfs(struct mmc_host *host)
 		goto err_node;
 #endif
 #ifdef CONFIG_FAIL_MMC_REQUEST
-	host->fail_mmc_request = fail_mmc_request;
+	host->fail_mmc_request = fail_default_attr;
 	if (IS_ERR(fault_create_debugfs_attr("fail_mmc_request",
 					     root,
 					     &host->fail_mmc_request)))
-- 
1.7.4.1

[PATCH v2 3/3] fault-injection: update documentation with the mmc module param

[Per Forlin]

Signed-off-by: Per Forlin <per.forlin@linaro.org>
---
 Documentation/fault-injection/fault-injection.txt |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index 70f924e..ba4be8b 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -121,7 +121,7 @@ use the boot option:
 	failslab=
 	fail_page_alloc=
 	fail_make_request=
-	fail_mmc_request=<interval>,<probability>,<space>,<times>
+	mmc_core.fail_request=<interval>,<probability>,<space>,<times>
 
 How to add new fault injection capability
 -----------------------------------------
-- 
1.7.4.1

Re: [PATCH v2 2/3] mmc: add module param to set fault injection attributes

[Akinobu Mita]

2011/9/14 Per Forlin <per.forlin@linaro.org>:

> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +
> +static DECLARE_FAULT_ATTR(fail_default_attr);
> +static char *fail_request;

This is not used anymore and ...

> +static int fail_mmc_request_param_set(const char *val,
> +                                     const struct kernel_param *kp)
> +{
> +       setup_fault_attr(&fail_default_attr, (char *) val);
> +       return 0;
> +}
> +
> +static const struct kernel_param_ops fail_mmc_request_param_ops = {
> +       .set = fail_mmc_request_param_set
> +};
> +module_param_cb(fail_request, &fail_mmc_request_param_ops,
> +               &fail_request, 0);

you can change this third parameter to NULL.

> +
> +#endif /* CONFIG_FAIL_MMC_REQUEST */

Re: [PATCH v2 2/3] mmc: add module param to set fault injection attributes

[Per Forlin]

On 14 September 2011 12:05, Akinobu Mita <akinobu.mita@gmail.com> wrote:
> 2011/9/14 Per Forlin <per.forlin@linaro.org>:
>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +
>> +static DECLARE_FAULT_ATTR(fail_default_attr);
>> +static char *fail_request;
>
> This is not used anymore and ...
>
Yes of course. Will remove it.

>> +static int fail_mmc_request_param_set(const char *val,
>> +                                     const struct kernel_param *kp)
>> +{
>> +       setup_fault_attr(&fail_default_attr, (char *) val);
>> +       return 0;
>> +}
>> +
>> +static const struct kernel_param_ops fail_mmc_request_param_ops = {
>> +       .set = fail_mmc_request_param_set
>> +};
>> +module_param_cb(fail_request, &fail_mmc_request_param_ops,
>> +               &fail_request, 0);
>
> you can change this third parameter to NULL.
>
Absolutely..

Thanks,
Per

Re: [PATCH v2 2/3] mmc: add module param to set fault injection attributes

[Per Forlin]

On 14 September 2011 12:18, Per Forlin <per.forlin@linaro.org> wrote:
> On 14 September 2011 12:05, Akinobu Mita <akinobu.mita@gmail.com> wrote:
>> 2011/9/14 Per Forlin <per.forlin@linaro.org>:
>>
>>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>>> +
>>> +static DECLARE_FAULT_ATTR(fail_default_attr);
>>> +static char *fail_request;
>>
>> This is not used anymore and ...
>>
> Yes of course. Will remove it.
>
>>> +static int fail_mmc_request_param_set(const char *val,
>>> +                                     const struct kernel_param *kp)
>>> +{
>>> +       setup_fault_attr(&fail_default_attr, (char *) val);
I am thinking of returning failure here if setup_fault_attr() fails.
if (setup_fault_attr(&fail_default_attr, (char *) val) == 0)
  return -EINVAL;

There will be a printk(KERN_WARNING "FAULT_INJECTION: failed to parse
arguments) it setup() fails. Is it too harsh to return failure?

Regards,
Per

Re: [PATCH v2 2/3] mmc: add module param to set fault injection attributes

[Per Forlin]

On 14 September 2011 12:38, Per Forlin <per.forlin@linaro.org> wrote:
> On 14 September 2011 12:18, Per Forlin <per.forlin@linaro.org> wrote:
>> On 14 September 2011 12:05, Akinobu Mita <akinobu.mita@gmail.com> wrote:
>>> 2011/9/14 Per Forlin <per.forlin@linaro.org>:
>>>
>>>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>>>> +
>>>> +static DECLARE_FAULT_ATTR(fail_default_attr);
>>>> +static char *fail_request;
>>>
>>> This is not used anymore and ...
>>>
>> Yes of course. Will remove it.
>>
>>>> +static int fail_mmc_request_param_set(const char *val,
>>>> +                                     const struct kernel_param *kp)
>>>> +{
>>>> +       setup_fault_attr(&fail_default_attr, (char *) val);
> I am thinking of returning failure here if setup_fault_attr() fails.
> if (setup_fault_attr(&fail_default_attr, (char *) val) == 0)
>  return -EINVAL;
>
> There will be a printk(KERN_WARNING "FAULT_INJECTION: failed to parse
> arguments) it setup() fails. Is it too harsh to return failure?
>
If error is returned here the kernel prints: "invalid for parameter
`mmc_core.fail_request'"
This piece of information is a reason for returning error on failure.

Regards,
Per

Re: [PATCH v2 2/3] mmc: add module param to set fault injection attributes

[Akinobu Mita]

2011/9/14 Per Forlin <per.forlin@linaro.org>:

>>>> +static int fail_mmc_request_param_set(const char *val,
>>>> +                                     const struct kernel_param *kp)
>>>> +{
>>>> +       setup_fault_attr(&fail_default_attr, (char *) val);
> I am thinking of returning failure here if setup_fault_attr() fails.
> if (setup_fault_attr(&fail_default_attr, (char *) val) == 0)
>  return -EINVAL;

It's good idea and it also prevents from loading the module if invalid
parameter is specified.

> There will be a printk(KERN_WARNING "FAULT_INJECTION: failed to parse
> arguments) it setup() fails. Is it too harsh to return failure?

Yes.  I'll try to fix in the future.