[PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Per Forlin]

change log:
 v2 - Resolve build issue in mmc core.c due to multiple init_module by
      removing the fault inject module.
    - Export fault injection functions to make them available for modules
    - Update fault injection documentation on MMC IO  
 v3 - add function descriptions in core.c
    - use export GPL for fault injection functions
 v4 - make the fault_attr per host. This prepares for upcoming patch from
      Akinobu that adds support for creating debugfs entries in
      arbitrary directory.
 v5 - Make use of fault_create_debugfs_attr() in Akinobu's
      patch "fault-injection: add ability to export fault_attr in...". 
 v6 - Fix typo in commit message in patch "export fault injection functions"
 v7 - Don't compile in boot param setup function if mmc-core is
      built as module.
 v8 - Update fault injection documentation.
      Add fail_mmc_request to boot option section. 

Per Forlin (3):
  fault-inject: export fault injection functions
  mmc: core: add random fault injection
  fault injection: add documentation on MMC IO fault injection

 Documentation/fault-injection/fault-injection.txt |    8 +++-
 drivers/mmc/core/core.c                           |   44 +++++++++++++++++++++
 drivers/mmc/core/debugfs.c                        |   27 +++++++++++++
 include/linux/mmc/host.h                          |    7 +++
 lib/Kconfig.debug                                 |   11 +++++
 lib/fault-inject.c                                |    2 +
 6 files changed, 98 insertions(+), 1 deletions(-)

-- 
1.7.4.1

[PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Per Forlin]

change log:
 v2 - Resolve build issue in mmc core.c due to multiple init_module by
      removing the fault inject module.
    - Export fault injection functions to make them available for modules
    - Update fault injection documentation on MMC IO  
 v3 - add function descriptions in core.c
    - use export GPL for fault injection functions
 v4 - make the fault_attr per host. This prepares for upcoming patch from
      Akinobu that adds support for creating debugfs entries in
      arbitrary directory.
 v5 - Make use of fault_create_debugfs_attr() in Akinobu's
      patch "fault-injection: add ability to export fault_attr in...". 
 v6 - Fix typo in commit message in patch "export fault injection functions"
 v7 - Don't compile in boot param setup function if mmc-core is
      built as module.
 v8 - Update fault injection documentation.
      Add fail_mmc_request to boot option section. 

Per Forlin (3):
  fault-inject: export fault injection functions
  mmc: core: add random fault injection
  fault injection: add documentation on MMC IO fault injection

 Documentation/fault-injection/fault-injection.txt |    8 +++-
 drivers/mmc/core/core.c                           |   44 +++++++++++++++++++++
 drivers/mmc/core/debugfs.c                        |   27 +++++++++++++
 include/linux/mmc/host.h                          |    7 +++
 lib/Kconfig.debug                                 |   11 +++++
 lib/fault-inject.c                                |    2 +
 6 files changed, 98 insertions(+), 1 deletions(-)

-- 
1.7.4.1

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[PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Per Forlin]

change log:
 v2 - Resolve build issue in mmc core.c due to multiple init_module by
      removing the fault inject module.
    - Export fault injection functions to make them available for modules
    - Update fault injection documentation on MMC IO  
 v3 - add function descriptions in core.c
    - use export GPL for fault injection functions
 v4 - make the fault_attr per host. This prepares for upcoming patch from
      Akinobu that adds support for creating debugfs entries in
      arbitrary directory.
 v5 - Make use of fault_create_debugfs_attr() in Akinobu's
      patch "fault-injection: add ability to export fault_attr in...". 
 v6 - Fix typo in commit message in patch "export fault injection functions"
 v7 - Don't compile in boot param setup function if mmc-core is
      built as module.
 v8 - Update fault injection documentation.
      Add fail_mmc_request to boot option section. 

Per Forlin (3):
  fault-inject: export fault injection functions
  mmc: core: add random fault injection
  fault injection: add documentation on MMC IO fault injection

 Documentation/fault-injection/fault-injection.txt |    8 +++-
 drivers/mmc/core/core.c                           |   44 +++++++++++++++++++++
 drivers/mmc/core/debugfs.c                        |   27 +++++++++++++
 include/linux/mmc/host.h                          |    7 +++
 lib/Kconfig.debug                                 |   11 +++++
 lib/fault-inject.c                                |    2 +
 6 files changed, 98 insertions(+), 1 deletions(-)

-- 
1.7.4.1

[PATCH --mmotm v8 1/3] fault-inject: export fault injection functions

[Per Forlin]

export symbols should_fail() and fault_create_debugfs_attr() in order
to let modules utilize the fault injection

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 lib/fault-inject.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index f193b77..328d433 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -130,6 +130,7 @@ bool should_fail(struct fault_attr *attr, ssize_t size)
 
 	return true;
 }
+EXPORT_SYMBOL_GPL(should_fail);
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 
@@ -243,5 +244,6 @@ fail:
 
 	return ERR_PTR(-ENOMEM);
 }
+EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
 
 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
-- 
1.7.4.1

[PATCH --mmotm v8 1/3] fault-inject: export fault injection functions

[Per Forlin]

export symbols should_fail() and fault_create_debugfs_attr() in order
to let modules utilize the fault injection

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 lib/fault-inject.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index f193b77..328d433 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -130,6 +130,7 @@ bool should_fail(struct fault_attr *attr, ssize_t size)
 
 	return true;
 }
+EXPORT_SYMBOL_GPL(should_fail);
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 
@@ -243,5 +244,6 @@ fail:
 
 	return ERR_PTR(-ENOMEM);
 }
+EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
 
 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
-- 
1.7.4.1

--
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[PATCH --mmotm v8 1/3] fault-inject: export fault injection functions

[Per Forlin]

export symbols should_fail() and fault_create_debugfs_attr() in order
to let modules utilize the fault injection

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 lib/fault-inject.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index f193b77..328d433 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -130,6 +130,7 @@ bool should_fail(struct fault_attr *attr, ssize_t size)
 
 	return true;
 }
+EXPORT_SYMBOL_GPL(should_fail);
 
 #ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
 
@@ -243,5 +244,6 @@ fail:
 
 	return ERR_PTR(-ENOMEM);
 }
+EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
 
 #endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
-- 
1.7.4.1

--
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[PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[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

[PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[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>

[PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[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

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Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[Linus Walleij]

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

Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[Linus Walleij]

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

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Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[Per Forlin]

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

Re: [PATCH --mmotm v8 2/3] mmc: core: add random fault injection

[Per Forlin]

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

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[PATCH --mmotm v8 3/3] fault injection: add documentation on MMC IO fault injection

[Per Forlin]

Add description on how to enable random fault injection
for MMC IO

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 Documentation/fault-injection/fault-injection.txt |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index 82a5d25..70f924e 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -21,6 +21,11 @@ o fail_make_request
   /sys/block/<device>/make-it-fail or
   /sys/block/<device>/<partition>/make-it-fail. (generic_make_request())
 
+o fail_mmc_request
+
+  injects MMC data errors on devices permitted by setting
+  debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
+
 Configure fault-injection capabilities behavior
 -----------------------------------------------
 
@@ -115,7 +120,8 @@ use the boot option:
 
 	failslab=
 	fail_page_alloc=
-	fail_make_request=<interval>,<probability>,<space>,<times>
+	fail_make_request=
+	fail_mmc_request=<interval>,<probability>,<space>,<times>
 
 How to add new fault injection capability
 -----------------------------------------
-- 
1.7.4.1

[PATCH --mmotm v8 3/3] fault injection: add documentation on MMC IO fault injection

[Per Forlin]

Add description on how to enable random fault injection
for MMC IO

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 Documentation/fault-injection/fault-injection.txt |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index 82a5d25..70f924e 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -21,6 +21,11 @@ o fail_make_request
   /sys/block/<device>/make-it-fail or
   /sys/block/<device>/<partition>/make-it-fail. (generic_make_request())
 
+o fail_mmc_request
+
+  injects MMC data errors on devices permitted by setting
+  debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
+
 Configure fault-injection capabilities behavior
 -----------------------------------------------
 
@@ -115,7 +120,8 @@ use the boot option:
 
 	failslab=
 	fail_page_alloc=
-	fail_make_request=<interval>,<probability>,<space>,<times>
+	fail_make_request=
+	fail_mmc_request=<interval>,<probability>,<space>,<times>
 
 How to add new fault injection capability
 -----------------------------------------
-- 
1.7.4.1

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[PATCH --mmotm v8 3/3] fault injection: add documentation on MMC IO fault injection

[Per Forlin]

Add description on how to enable random fault injection
for MMC IO

Signed-off-by: Per Forlin <per.forlin@linaro.org>
Acked-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 Documentation/fault-injection/fault-injection.txt |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
index 82a5d25..70f924e 100644
--- a/Documentation/fault-injection/fault-injection.txt
+++ b/Documentation/fault-injection/fault-injection.txt
@@ -21,6 +21,11 @@ o fail_make_request
   /sys/block/<device>/make-it-fail or
   /sys/block/<device>/<partition>/make-it-fail. (generic_make_request())
 
+o fail_mmc_request
+
+  injects MMC data errors on devices permitted by setting
+  debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
+
 Configure fault-injection capabilities behavior
 -----------------------------------------------
 
@@ -115,7 +120,8 @@ use the boot option:
 
 	failslab=
 	fail_page_alloc=
-	fail_make_request=<interval>,<probability>,<space>,<times>
+	fail_make_request=
+	fail_mmc_request=<interval>,<probability>,<space>,<times>
 
 How to add new fault injection capability
 -----------------------------------------
-- 
1.7.4.1

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Re: [PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Per Forlin]

Hi Chris,

It's no longer necessary to merge this through the mm-tree since
Akinobu's patch "fault-injection: add ability to export fault_attr in
arbitrary directory" is in mainline.
Chris, would you mind merging the fault-injection patches in this
patchset to mmc-next once the mmc part of this patchset is acked and
accepted?

Regards,
Per

On 9 August 2011 14:07, Per Forlin <per.forlin@linaro.org> wrote:
> change log:
>  v2 - Resolve build issue in mmc core.c due to multiple init_module by
>      removing the fault inject module.
>    - Export fault injection functions to make them available for modules
>    - Update fault injection documentation on MMC IO
>  v3 - add function descriptions in core.c
>    - use export GPL for fault injection functions
>  v4 - make the fault_attr per host. This prepares for upcoming patch from
>      Akinobu that adds support for creating debugfs entries in
>      arbitrary directory.
>  v5 - Make use of fault_create_debugfs_attr() in Akinobu's
>      patch "fault-injection: add ability to export fault_attr in...".
>  v6 - Fix typo in commit message in patch "export fault injection functions"
>  v7 - Don't compile in boot param setup function if mmc-core is
>      built as module.
>  v8 - Update fault injection documentation.
>      Add fail_mmc_request to boot option section.
>
> Per Forlin (3):
>  fault-inject: export fault injection functions
>  mmc: core: add random fault injection
>  fault injection: add documentation on MMC IO fault injection
>
>  Documentation/fault-injection/fault-injection.txt |    8 +++-
>  drivers/mmc/core/core.c                           |   44 +++++++++++++++++++++
>  drivers/mmc/core/debugfs.c                        |   27 +++++++++++++
>  include/linux/mmc/host.h                          |    7 +++
>  lib/Kconfig.debug                                 |   11 +++++
>  lib/fault-inject.c                                |    2 +
>  6 files changed, 98 insertions(+), 1 deletions(-)
>
> --
> 1.7.4.1
>
>

Re: [PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Per Forlin]

Hi Chris,

It's no longer necessary to merge this through the mm-tree since
Akinobu's patch "fault-injection: add ability to export fault_attr in
arbitrary directory" is in mainline.
Chris, would you mind merging the fault-injection patches in this
patchset to mmc-next once the mmc part of this patchset is acked and
accepted?

Regards,
Per

On 9 August 2011 14:07, Per Forlin <per.forlin@linaro.org> wrote:
> change log:
>  v2 - Resolve build issue in mmc core.c due to multiple init_module by
>      removing the fault inject module.
>    - Export fault injection functions to make them available for modules
>    - Update fault injection documentation on MMC IO
>  v3 - add function descriptions in core.c
>    - use export GPL for fault injection functions
>  v4 - make the fault_attr per host. This prepares for upcoming patch from
>      Akinobu that adds support for creating debugfs entries in
>      arbitrary directory.
>  v5 - Make use of fault_create_debugfs_attr() in Akinobu's
>      patch "fault-injection: add ability to export fault_attr in...".
>  v6 - Fix typo in commit message in patch "export fault injection functions"
>  v7 - Don't compile in boot param setup function if mmc-core is
>      built as module.
>  v8 - Update fault injection documentation.
>      Add fail_mmc_request to boot option section.
>
> Per Forlin (3):
>  fault-inject: export fault injection functions
>  mmc: core: add random fault injection
>  fault injection: add documentation on MMC IO fault injection
>
>  Documentation/fault-injection/fault-injection.txt |    8 +++-
>  drivers/mmc/core/core.c                           |   44 +++++++++++++++++++++
>  drivers/mmc/core/debugfs.c                        |   27 +++++++++++++
>  include/linux/mmc/host.h                          |    7 +++
>  lib/Kconfig.debug                                 |   11 +++++
>  lib/fault-inject.c                                |    2 +
>  6 files changed, 98 insertions(+), 1 deletions(-)
>
> --
> 1.7.4.1
>
>

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Re: [PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Chris Ball]

Hi Per,

On Fri, Aug 19 2011, Per Forlin wrote:
> Hi Chris,
>
> It's no longer necessary to merge this through the mm-tree since
> Akinobu's patch "fault-injection: add ability to export fault_attr in
> arbitrary directory" is in mainline.
> Chris, would you mind merging the fault-injection patches in this
> patchset to mmc-next once the mmc part of this patchset is acked and
> accepted?

That's fine -- merged to mmc-next for 3.2 now, with Linus W's review.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

Re: [PATCH --mmotm v8 0/3] Make fault injection available for MMC IO

[Chris Ball]

Hi Per,

On Fri, Aug 19 2011, Per Forlin wrote:
> Hi Chris,
>
> It's no longer necessary to merge this through the mm-tree since
> Akinobu's patch "fault-injection: add ability to export fault_attr in
> arbitrary directory" is in mainline.
> Chris, would you mind merging the fault-injection patches in this
> patchset to mmc-next once the mmc part of this patchset is acked and
> accepted?

That's fine -- merged to mmc-next for 3.2 now, with Linus W's review.

Thanks,

- Chris.
-- 
Chris Ball   <cjb@laptop.org>   <http://printf.net/>
One Laptop Per Child

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