* [PATCH --mmotm v8 2/3] mmc: core: add random fault injection
@ 2011-08-09 12:07 ` Per Forlin
0 siblings, 0 replies; 20+ messages in thread
From: Per Forlin @ 2011-08-09 12:07 UTC (permalink / raw)
To: Akinobu Mita, akpm, Linus Walleij, linux-kernel, Randy Dunlap,
Chris Ball
Cc: linux-doc, linux-mmc, linaro-dev, linux-mm, Per Forlin
This adds support to inject data errors after a completed host transfer.
The mmc core will return error even though the host transfer is successful.
This simple fault injection proved to be very useful to test the
non-blocking error handling in the mmc_blk_issue_rw_rq().
Random faults can also test how the host driver handles pre_req()
and post_req() in case of errors.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
drivers/mmc/core/core.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/debugfs.c | 27 +++++++++++++++++++++++++++
include/linux/mmc/host.h | 7 +++++++
lib/Kconfig.debug | 11 +++++++++++
4 files changed, 89 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 89bdeae..a4996b0 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -25,6 +25,11 @@
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
+#ifdef CONFIG_FAIL_MMC_REQUEST
+#include <linux/fault-inject.h>
+#include <linux/random.h>
+#endif
+
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
@@ -83,6 +88,43 @@ static void mmc_flush_scheduled_work(void)
flush_workqueue(workqueue);
}
+#ifdef CONFIG_FAIL_MMC_REQUEST
+
+/*
+ * Internal function. Inject random data errors.
+ * If mmc_data is NULL no errors are injected.
+ */
+static void mmc_should_fail_request(struct mmc_host *host,
+ struct mmc_request *mrq)
+{
+ struct mmc_command *cmd = mrq->cmd;
+ struct mmc_data *data = mrq->data;
+ static const int data_errors[] = {
+ -ETIMEDOUT,
+ -EILSEQ,
+ -EIO,
+ };
+
+ if (!data)
+ return;
+
+ if (cmd->error || data->error ||
+ !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
+ return;
+
+ data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
+ data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
+}
+
+#else /* CONFIG_FAIL_MMC_REQUEST */
+
+static void mmc_should_fail_request(struct mmc_host *host,
+ struct mmc_request *mrq)
+{
+}
+
+#endif /* CONFIG_FAIL_MMC_REQUEST */
+
/**
* mmc_request_done - finish processing an MMC request
* @host: MMC host which completed request
@@ -109,6 +151,8 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
cmd->error = 0;
host->ops->request(host, mrq);
} else {
+ mmc_should_fail_request(host, mrq);
+
led_trigger_event(host->led, LED_OFF);
pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n",
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index f573753..189581d 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -13,6 +13,9 @@
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/stat.h>
+#ifdef CONFIG_FAIL_MMC_REQUEST
+#include <linux/fault-inject.h>
+#endif
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -159,6 +162,23 @@ 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");
@@ -189,6 +209,13 @@ void mmc_add_host_debugfs(struct mmc_host *host)
root, &host->clk_delay))
goto err_node;
#endif
+#ifdef CONFIG_FAIL_MMC_REQUEST
+ host->fail_mmc_request = fail_mmc_request;
+ if (IS_ERR(fault_create_debugfs_attr("fail_mmc_request",
+ root,
+ &host->fail_mmc_request)))
+ goto err_node;
+#endif
return;
err_node:
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 0f83858..ee472fe 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -12,6 +12,9 @@
#include <linux/leds.h>
#include <linux/sched.h>
+#ifdef CONFIG_FAIL_MMC_REQUEST
+#include <linux/fault-inject.h>
+#endif
#include <linux/mmc/core.h>
#include <linux/mmc/pm.h>
@@ -304,6 +307,10 @@ struct mmc_host {
struct mmc_async_req *areq; /* active async req */
+#ifdef CONFIG_FAIL_MMC_REQUEST
+ struct fault_attr fail_mmc_request;
+#endif
+
unsigned long private[0] ____cacheline_aligned;
};
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 47879c7..ebff0c9 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1090,6 +1090,17 @@ config FAIL_IO_TIMEOUT
Only works with drivers that use the generic timeout handling,
for others it wont do anything.
+config FAIL_MMC_REQUEST
+ bool "Fault-injection capability for MMC IO"
+ select DEBUG_FS
+ depends on FAULT_INJECTION && MMC
+ help
+ Provide fault-injection capability for MMC IO.
+ This will make the mmc core return data errors. This is
+ useful to test the error handling in the mmc block device
+ and to test how the mmc host driver handles retries from
+ the block device.
+
config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS && DEBUG_FS
--
1.7.4.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH --mmotm v8 2/3] mmc: core: add random fault injection
@ 2011-08-09 12:07 ` Per Forlin
0 siblings, 0 replies; 20+ messages in thread
From: Per Forlin @ 2011-08-09 12:07 UTC (permalink / raw)
To: Akinobu Mita, akpm, Linus Walleij, linux-kernel, Randy Dunlap, Chri
Cc: linux-doc, linux-mmc, linaro-dev, linux-mm, Per Forlin
This adds support to inject data errors after a completed host transfer.
The mmc core will return error even though the host transfer is successful.
This simple fault injection proved to be very useful to test the
non-blocking error handling in the mmc_blk_issue_rw_rq().
Random faults can also test how the host driver handles pre_req()
and post_req() in case of errors.
Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
drivers/mmc/core/core.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/debugfs.c | 27 +++++++++++++++++++++++++++
include/linux/mmc/host.h | 7 +++++++
lib/Kconfig.debug | 11 +++++++++++
4 files changed, 89 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 89bdeae..a4996b0 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -25,6 +25,11 @@
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
+#ifdef CONFIG_FAIL_MMC_REQUEST
+#include <linux/fault-inject.h>
+#include <linux/random.h>
+#endif
+
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
@@ -83,6 +88,43 @@ static void mmc_flush_scheduled_work(void)
flush_workqueue(workqueue);
}
+#ifdef CONFIG_FAIL_MMC_REQUEST
+
+/*
+ * Internal function. Inject random data errors.
+ * If mmc_data is NULL no errors are injected.
+ */
+static void mmc_should_fail_request(struct mmc_host *host,
+ struct mmc_request *mrq)
+{
+ struct mmc_command *cmd = mrq->cmd;
+ struct mmc_data *data = mrq->data;
+ static const int data_errors[] = {
+ -ETIMEDOUT,
+ -EILSEQ,
+ -EIO,
+ };
+
+ if (!data)
+ return;
+
+ if (cmd->error || data->error ||
+ !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
+ return;
+
+ data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
+ data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
+}
+
+#else /* CONFIG_FAIL_MMC_REQUEST */
+
+static void mmc_should_fail_request(struct mmc_host *host,
+ struct mmc_request *mrq)
+{
+}
+
+#endif /* CONFIG_FAIL_MMC_REQUEST */
+
/**
* mmc_request_done - finish processing an MMC request
* @host: MMC host which completed request
@@ -109,6 +151,8 @@ void mmc_request_done(struct mmc_host *host, struct mmc_request *mrq)
cmd->error = 0;
host->ops->request(host, mrq);
} else {
+ mmc_should_fail_request(host, mrq);
+
led_trigger_event(host->led, LED_OFF);
pr_debug("%s: req done (CMD%u): %d: %08x %08x %08x %08x\n",
diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index f573753..189581d 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -13,6 +13,9 @@
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/stat.h>
+#ifdef CONFIG_FAIL_MMC_REQUEST
+#include <linux/fault-inject.h>
+#endif
#include <linux/mmc/card.h>
#include <linux/mmc/host.h>
@@ -159,6 +162,23 @@ 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");
@@ -189,6 +209,13 @@ void mmc_add_host_debugfs(struct mmc_host *host)
root, &host->clk_delay))
goto err_node;
#endif
+#ifdef CONFIG_FAIL_MMC_REQUEST
+ host->fail_mmc_request = fail_mmc_request;
+ if (IS_ERR(fault_create_debugfs_attr("fail_mmc_request",
+ root,
+ &host->fail_mmc_request)))
+ goto err_node;
+#endif
return;
err_node:
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 0f83858..ee472fe 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -12,6 +12,9 @@
#include <linux/leds.h>
#include <linux/sched.h>
+#ifdef CONFIG_FAIL_MMC_REQUEST
+#include <linux/fault-inject.h>
+#endif
#include <linux/mmc/core.h>
#include <linux/mmc/pm.h>
@@ -304,6 +307,10 @@ struct mmc_host {
struct mmc_async_req *areq; /* active async req */
+#ifdef CONFIG_FAIL_MMC_REQUEST
+ struct fault_attr fail_mmc_request;
+#endif
+
unsigned long private[0] ____cacheline_aligned;
};
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 47879c7..ebff0c9 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1090,6 +1090,17 @@ config FAIL_IO_TIMEOUT
Only works with drivers that use the generic timeout handling,
for others it wont do anything.
+config FAIL_MMC_REQUEST
+ bool "Fault-injection capability for MMC IO"
+ select DEBUG_FS
+ depends on FAULT_INJECTION && MMC
+ help
+ Provide fault-injection capability for MMC IO.
+ This will make the mmc core return data errors. This is
+ useful to test the error handling in the mmc block device
+ and to test how the mmc host driver handles retries from
+ the block device.
+
config FAULT_INJECTION_DEBUG_FS
bool "Debugfs entries for fault-injection capabilities"
depends on FAULT_INJECTION && SYSFS && DEBUG_FS
--
1.7.4.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection
2011-08-09 12:07 ` Per Forlin
@ 2011-08-19 11:40 ` Linus Walleij
-1 siblings, 0 replies; 20+ messages in thread
From: Linus Walleij @ 2011-08-19 11:40 UTC (permalink / raw)
To: Per Forlin
Cc: Akinobu Mita, akpm, Linus Walleij, linux-kernel, Randy Dunlap,
Chris Ball, linux-doc, linux-mmc, linaro-dev, linux-mm
On Tue, Aug 9, 2011 at 2:07 PM, Per Forlin <per.forlin@linaro.org> wrote:
> This adds support to inject data errors after a completed host transfer.
> The mmc core will return error even though the host transfer is successful.
> This simple fault injection proved to be very useful to test the
> non-blocking error handling in the mmc_blk_issue_rw_rq().
> Random faults can also test how the host driver handles pre_req()
> and post_req() in case of errors.
Good idea!
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 89bdeae..a4996b0 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -25,6 +25,11 @@
> #include <linux/pm_runtime.h>
> #include <linux/suspend.h>
>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +#include <linux/fault-inject.h>
> +#include <linux/random.h>
> +#endif
You don't need to #ifdef around the #include <> stuff, and if you
do, something is wrong with those headers. It's just a bunch of defines
that aren't used in some circumstances. Stack them with the others,
simply, just #ifdef the code below.
> @@ -83,6 +88,43 @@ static void mmc_flush_scheduled_work(void)
> flush_workqueue(workqueue);
> }
>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +
> +/*
> + * Internal function. Inject random data errors.
> + * If mmc_data is NULL no errors are injected.
> + */
> +static void mmc_should_fail_request(struct mmc_host *host,
> + struct mmc_request *mrq)
> +{
> + struct mmc_command *cmd = mrq->cmd;
> + struct mmc_data *data = mrq->data;
> + static const int data_errors[] = {
> + -ETIMEDOUT,
> + -EILSEQ,
> + -EIO,
> + };
> +
> + if (!data)
> + return;
> +
> + if (cmd->error || data->error ||
> + !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
> + return;
> +
> + data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
> + data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
> +}
> +
> +#else /* CONFIG_FAIL_MMC_REQUEST */
> +
> +static void mmc_should_fail_request(struct mmc_host *host,
> + struct mmc_request *mrq)
Should be "static inline" so we know it will be folded in and nullified
by the compiler, lots of kernel code use that pattern.
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index f573753..189581d 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -13,6 +13,9 @@
> #include <linux/seq_file.h>
> #include <linux/slab.h>
> #include <linux/stat.h>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +#include <linux/fault-inject.h>
> +#endif
No #ifdef:ing...
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 0f83858..ee472fe 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -12,6 +12,9 @@
>
> #include <linux/leds.h>
> #include <linux/sched.h>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +#include <linux/fault-inject.h>
> +#endif
Neither here...
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 47879c7..ebff0c9 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
I'm contemplating if we should create drivers/mmc/Kconfig.debug
and stash this in there instead, i.e. also move out MMC_DEBUG
from drivers/mmc/Kconfig and add to that?
It seems more apropriate to select this from the MMC subsystem.
However the core of fault injection is in lib/
So maybe a simple:
config FAIL_MMC_REQUEST
bool
select FAULT_INJECTION
That can then be selected by a debug option in the MMC subsystem?
I fear it may be hard to find this otherwise...
(NB: I have very little clue how the Kconfig.debug files get sourced
into the Kbuild so I might be misguided...)
> @@ -1090,6 +1090,17 @@ config FAIL_IO_TIMEOUT
> Only works with drivers that use the generic timeout handling,
> for others it wont do anything.
>
> +config FAIL_MMC_REQUEST
> + bool "Fault-injection capability for MMC IO"
> + select DEBUG_FS
> + depends on FAULT_INJECTION && MMC
Isn't:
depends on MMC
select FAULT_INJECTION
Simpler to use? Now you have to select fault injection first
to even see this option right?
Apart from this it looks fine.
Thanks,
Linus Walleij
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection
@ 2011-08-19 11:40 ` Linus Walleij
0 siblings, 0 replies; 20+ messages in thread
From: Linus Walleij @ 2011-08-19 11:40 UTC (permalink / raw)
To: Per Forlin
Cc: Akinobu Mita, akpm, Linus Walleij, linux-kernel, Randy Dunlap,
Chris Ball, linux-doc, linux-mmc, linaro-dev, linux-mm
On Tue, Aug 9, 2011 at 2:07 PM, Per Forlin <per.forlin@linaro.org> wrote:
> This adds support to inject data errors after a completed host transfer.
> The mmc core will return error even though the host transfer is successful.
> This simple fault injection proved to be very useful to test the
> non-blocking error handling in the mmc_blk_issue_rw_rq().
> Random faults can also test how the host driver handles pre_req()
> and post_req() in case of errors.
Good idea!
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 89bdeae..a4996b0 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -25,6 +25,11 @@
> #include <linux/pm_runtime.h>
> #include <linux/suspend.h>
>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +#include <linux/fault-inject.h>
> +#include <linux/random.h>
> +#endif
You don't need to #ifdef around the #include <> stuff, and if you
do, something is wrong with those headers. It's just a bunch of defines
that aren't used in some circumstances. Stack them with the others,
simply, just #ifdef the code below.
> @@ -83,6 +88,43 @@ static void mmc_flush_scheduled_work(void)
> flush_workqueue(workqueue);
> }
>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +
> +/*
> + * Internal function. Inject random data errors.
> + * If mmc_data is NULL no errors are injected.
> + */
> +static void mmc_should_fail_request(struct mmc_host *host,
> + struct mmc_request *mrq)
> +{
> + struct mmc_command *cmd = mrq->cmd;
> + struct mmc_data *data = mrq->data;
> + static const int data_errors[] = {
> + -ETIMEDOUT,
> + -EILSEQ,
> + -EIO,
> + };
> +
> + if (!data)
> + return;
> +
> + if (cmd->error || data->error ||
> + !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
> + return;
> +
> + data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
> + data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
> +}
> +
> +#else /* CONFIG_FAIL_MMC_REQUEST */
> +
> +static void mmc_should_fail_request(struct mmc_host *host,
> + struct mmc_request *mrq)
Should be "static inline" so we know it will be folded in and nullified
by the compiler, lots of kernel code use that pattern.
> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
> index f573753..189581d 100644
> --- a/drivers/mmc/core/debugfs.c
> +++ b/drivers/mmc/core/debugfs.c
> @@ -13,6 +13,9 @@
> #include <linux/seq_file.h>
> #include <linux/slab.h>
> #include <linux/stat.h>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +#include <linux/fault-inject.h>
> +#endif
No #ifdef:ing...
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 0f83858..ee472fe 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -12,6 +12,9 @@
>
> #include <linux/leds.h>
> #include <linux/sched.h>
> +#ifdef CONFIG_FAIL_MMC_REQUEST
> +#include <linux/fault-inject.h>
> +#endif
Neither here...
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 47879c7..ebff0c9 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
I'm contemplating if we should create drivers/mmc/Kconfig.debug
and stash this in there instead, i.e. also move out MMC_DEBUG
from drivers/mmc/Kconfig and add to that?
It seems more apropriate to select this from the MMC subsystem.
However the core of fault injection is in lib/
So maybe a simple:
config FAIL_MMC_REQUEST
bool
select FAULT_INJECTION
That can then be selected by a debug option in the MMC subsystem?
I fear it may be hard to find this otherwise...
(NB: I have very little clue how the Kconfig.debug files get sourced
into the Kbuild so I might be misguided...)
> @@ -1090,6 +1090,17 @@ config FAIL_IO_TIMEOUT
> Only works with drivers that use the generic timeout handling,
> for others it wont do anything.
>
> +config FAIL_MMC_REQUEST
> + bool "Fault-injection capability for MMC IO"
> + select DEBUG_FS
> + depends on FAULT_INJECTION && MMC
Isn't:
depends on MMC
select FAULT_INJECTION
Simpler to use? Now you have to select fault injection first
to even see this option right?
Apart from this it looks fine.
Thanks,
Linus Walleij
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection
2011-08-19 11:40 ` Linus Walleij
@ 2011-08-19 12:13 ` Per Forlin
-1 siblings, 0 replies; 20+ messages in thread
From: Per Forlin @ 2011-08-19 12:13 UTC (permalink / raw)
To: Linus Walleij
Cc: Akinobu Mita, akpm, Linus Walleij, linux-kernel, Randy Dunlap,
Chris Ball, linux-doc, linux-mmc, linaro-dev, linux-mm,
J Freyensee
On 19 August 2011 13:40, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Tue, Aug 9, 2011 at 2:07 PM, Per Forlin <per.forlin@linaro.org> wrote:
>
>> This adds support to inject data errors after a completed host transfer.
>> The mmc core will return error even though the host transfer is successful.
>> This simple fault injection proved to be very useful to test the
>> non-blocking error handling in the mmc_blk_issue_rw_rq().
>> Random faults can also test how the host driver handles pre_req()
>> and post_req() in case of errors.
>
> Good idea!
>
Thanks.
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index 89bdeae..a4996b0 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -25,6 +25,11 @@
>> #include <linux/pm_runtime.h>
>> #include <linux/suspend.h>
>>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +#include <linux/fault-inject.h>
>> +#include <linux/random.h>
>> +#endif
>
> You don't need to #ifdef around the #include <> stuff, and if you
> do, something is wrong with those headers. It's just a bunch of defines
> that aren't used in some circumstances. Stack them with the others,
> simply, just #ifdef the code below.
>
I added them after suggestion from J Freyensee. I am also in favor of
no ifdefs here. I'll remove them in the next patchset unless James has
any strong objections.
>> @@ -83,6 +88,43 @@ static void mmc_flush_scheduled_work(void)
>> flush_workqueue(workqueue);
>> }
>>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +
>> +/*
>> + * Internal function. Inject random data errors.
>> + * If mmc_data is NULL no errors are injected.
>> + */
>> +static void mmc_should_fail_request(struct mmc_host *host,
>> + struct mmc_request *mrq)
>> +{
>> + struct mmc_command *cmd = mrq->cmd;
>> + struct mmc_data *data = mrq->data;
>> + static const int data_errors[] = {
>> + -ETIMEDOUT,
>> + -EILSEQ,
>> + -EIO,
>> + };
>> +
>> + if (!data)
>> + return;
>> +
>> + if (cmd->error || data->error ||
>> + !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
>> + return;
>> +
>> + data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
>> + data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
>> +}
>> +
>> +#else /* CONFIG_FAIL_MMC_REQUEST */
>> +
>> +static void mmc_should_fail_request(struct mmc_host *host,
>> + struct mmc_request *mrq)
>
> Should be "static inline" so we know it will be folded in and nullified
> by the compiler, lots of kernel code use that pattern.
>
I'll fix.
>> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>> index f573753..189581d 100644
>> --- a/drivers/mmc/core/debugfs.c
>> +++ b/drivers/mmc/core/debugfs.c
>> @@ -13,6 +13,9 @@
>> #include <linux/seq_file.h>
>> #include <linux/slab.h>
>> #include <linux/stat.h>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +#include <linux/fault-inject.h>
>> +#endif
>
> No #ifdef:ing...
>
I'll remove it.
>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>> index 0f83858..ee472fe 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -12,6 +12,9 @@
>>
>> #include <linux/leds.h>
>> #include <linux/sched.h>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +#include <linux/fault-inject.h>
>> +#endif
>
> Neither here...
>
dito
>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>> index 47879c7..ebff0c9 100644
>> --- a/lib/Kconfig.debug
>> +++ b/lib/Kconfig.debug
>
> I'm contemplating if we should create drivers/mmc/Kconfig.debug
> and stash this in there instead, i.e. also move out MMC_DEBUG
> from drivers/mmc/Kconfig and add to that?
>
> It seems more apropriate to select this from the MMC subsystem.
> However the core of fault injection is in lib/
>
> So maybe a simple:
>
> config FAIL_MMC_REQUEST
> bool
> select FAULT_INJECTION
>
> That can then be selected by a debug option in the MMC subsystem?
> I fear it may be hard to find this otherwise...
>
> (NB: I have very little clue how the Kconfig.debug files get sourced
> into the Kbuild so I might be misguided...)
>
The FAIL_MMC_REQUEST sits right next to the rest of the fail injection
functions.
config FAILSLAB
depends on FAULT_INJECTION
depends on SLAB || SLUB
config FAIL_PAGE_ALLOC
depends on FAULT_INJECTION
config FAIL_MAKE_REQUEST
depends on FAULT_INJECTION && BLOCK
config FAIL_IO_TIMEOUT
depends on FAULT_INJECTION && BLOCK
config FAIL_MMC_REQUEST
select DEBUG_FS
depends on FAULT_INJECTION && MMC
I think the proper place is to have it here together with the rest.
>> @@ -1090,6 +1090,17 @@ config FAIL_IO_TIMEOUT
>> Only works with drivers that use the generic timeout handling,
>> for others it wont do anything.
>>
>> +config FAIL_MMC_REQUEST
>> + bool "Fault-injection capability for MMC IO"
>> + select DEBUG_FS
>> + depends on FAULT_INJECTION && MMC
>
> Isn't:
>
> depends on MMC
> select FAULT_INJECTION
>
> Simpler to use? Now you have to select fault injection first
> to even see this option right?
>
In menuconfig you have to select FAULT_INJECTION first, then you can
choose from a list of available fault injection options. I don't see
any real reason for treating FAIL_MMC_REQUEST different from the rest.
Thanks for your comments.
/Per
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection
@ 2011-08-19 12:13 ` Per Forlin
0 siblings, 0 replies; 20+ messages in thread
From: Per Forlin @ 2011-08-19 12:13 UTC (permalink / raw)
To: Linus Walleij
Cc: Akinobu Mita, akpm, Linus Walleij, linux-kernel, Randy Dunlap,
Chris Ball, linux-doc, linux-mmc, linaro-dev, linux-mm,
J Freyensee
On 19 August 2011 13:40, Linus Walleij <linus.walleij@linaro.org> wrote:
> On Tue, Aug 9, 2011 at 2:07 PM, Per Forlin <per.forlin@linaro.org> wrote:
>
>> This adds support to inject data errors after a completed host transfer.
>> The mmc core will return error even though the host transfer is successful.
>> This simple fault injection proved to be very useful to test the
>> non-blocking error handling in the mmc_blk_issue_rw_rq().
>> Random faults can also test how the host driver handles pre_req()
>> and post_req() in case of errors.
>
> Good idea!
>
Thanks.
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index 89bdeae..a4996b0 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -25,6 +25,11 @@
>> #include <linux/pm_runtime.h>
>> #include <linux/suspend.h>
>>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +#include <linux/fault-inject.h>
>> +#include <linux/random.h>
>> +#endif
>
> You don't need to #ifdef around the #include <> stuff, and if you
> do, something is wrong with those headers. It's just a bunch of defines
> that aren't used in some circumstances. Stack them with the others,
> simply, just #ifdef the code below.
>
I added them after suggestion from J Freyensee. I am also in favor of
no ifdefs here. I'll remove them in the next patchset unless James has
any strong objections.
>> @@ -83,6 +88,43 @@ static void mmc_flush_scheduled_work(void)
>> flush_workqueue(workqueue);
>> }
>>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +
>> +/*
>> + * Internal function. Inject random data errors.
>> + * If mmc_data is NULL no errors are injected.
>> + */
>> +static void mmc_should_fail_request(struct mmc_host *host,
>> + struct mmc_request *mrq)
>> +{
>> + struct mmc_command *cmd = mrq->cmd;
>> + struct mmc_data *data = mrq->data;
>> + static const int data_errors[] = {
>> + -ETIMEDOUT,
>> + -EILSEQ,
>> + -EIO,
>> + };
>> +
>> + if (!data)
>> + return;
>> +
>> + if (cmd->error || data->error ||
>> + !should_fail(&host->fail_mmc_request, data->blksz * data->blocks))
>> + return;
>> +
>> + data->error = data_errors[random32() % ARRAY_SIZE(data_errors)];
>> + data->bytes_xfered = (random32() % (data->bytes_xfered >> 9)) << 9;
>> +}
>> +
>> +#else /* CONFIG_FAIL_MMC_REQUEST */
>> +
>> +static void mmc_should_fail_request(struct mmc_host *host,
>> + struct mmc_request *mrq)
>
> Should be "static inline" so we know it will be folded in and nullified
> by the compiler, lots of kernel code use that pattern.
>
I'll fix.
>> diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
>> index f573753..189581d 100644
>> --- a/drivers/mmc/core/debugfs.c
>> +++ b/drivers/mmc/core/debugfs.c
>> @@ -13,6 +13,9 @@
>> #include <linux/seq_file.h>
>> #include <linux/slab.h>
>> #include <linux/stat.h>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +#include <linux/fault-inject.h>
>> +#endif
>
> No #ifdef:ing...
>
I'll remove it.
>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>> index 0f83858..ee472fe 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -12,6 +12,9 @@
>>
>> #include <linux/leds.h>
>> #include <linux/sched.h>
>> +#ifdef CONFIG_FAIL_MMC_REQUEST
>> +#include <linux/fault-inject.h>
>> +#endif
>
> Neither here...
>
dito
>> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>> index 47879c7..ebff0c9 100644
>> --- a/lib/Kconfig.debug
>> +++ b/lib/Kconfig.debug
>
> I'm contemplating if we should create drivers/mmc/Kconfig.debug
> and stash this in there instead, i.e. also move out MMC_DEBUG
> from drivers/mmc/Kconfig and add to that?
>
> It seems more apropriate to select this from the MMC subsystem.
> However the core of fault injection is in lib/
>
> So maybe a simple:
>
> config FAIL_MMC_REQUEST
> bool
> select FAULT_INJECTION
>
> That can then be selected by a debug option in the MMC subsystem?
> I fear it may be hard to find this otherwise...
>
> (NB: I have very little clue how the Kconfig.debug files get sourced
> into the Kbuild so I might be misguided...)
>
The FAIL_MMC_REQUEST sits right next to the rest of the fail injection
functions.
config FAILSLAB
depends on FAULT_INJECTION
depends on SLAB || SLUB
config FAIL_PAGE_ALLOC
depends on FAULT_INJECTION
config FAIL_MAKE_REQUEST
depends on FAULT_INJECTION && BLOCK
config FAIL_IO_TIMEOUT
depends on FAULT_INJECTION && BLOCK
config FAIL_MMC_REQUEST
select DEBUG_FS
depends on FAULT_INJECTION && MMC
I think the proper place is to have it here together with the rest.
>> @@ -1090,6 +1090,17 @@ config FAIL_IO_TIMEOUT
>> Only works with drivers that use the generic timeout handling,
>> for others it wont do anything.
>>
>> +config FAIL_MMC_REQUEST
>> + bool "Fault-injection capability for MMC IO"
>> + select DEBUG_FS
>> + depends on FAULT_INJECTION && MMC
>
> Isn't:
>
> depends on MMC
> select FAULT_INJECTION
>
> Simpler to use? Now you have to select fault injection first
> to even see this option right?
>
In menuconfig you have to select FAULT_INJECTION first, then you can
choose from a list of available fault injection options. I don't see
any real reason for treating FAIL_MMC_REQUEST different from the rest.
Thanks for your comments.
/Per
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
^ permalink raw reply [flat|nested] 20+ messages in thread