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Commit dd48c085 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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fault-injection: add ability to export fault_attr in arbitrary directory 



init_fault_attr_dentries() is used to export fault_attr via debugfs.
But it can only export it in debugfs root directory.

Per Forlin is working on mmc_fail_request which adds support to inject
data errors after a completed host transfer in MMC subsystem.

The fault_attr for mmc_fail_request should be defined per mmc host and
export it in debugfs directory per mmc host like
/sys/kernel/debug/mmc0/mmc_fail_request.

init_fault_attr_dentries() doesn't help for mmc_fail_request.  So this
introduces fault_create_debugfs_attr() which is able to create a
directory in the arbitrary directory and replace
init_fault_attr_dentries().

[akpm@linux-foundation.org: extraneous semicolon, per Randy]
Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Tested-by: default avatarPer Forlin <per.forlin@linaro.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent f48d1915

Documentation/fault-injection/fault-injection.txt

+1 −2
Original line number Diff line number Diff line
@@ -143,8 +143,7 @@ o provide a way to configure fault attributes 
  failslab, fail_page_alloc, and fail_make_request use this way.

  Helper functions:



	init_fault_attr_dentries(entries, attr, name);

	void cleanup_fault_attr_dentries(entries);

	fault_create_debugfs_attr(name, parent, attr);



- module parameters

block/blk-core.c

+4 −2
Original line number Diff line number Diff line
@@ -1368,8 +1368,10 @@ static bool should_fail_request(struct hd_struct *part, unsigned int bytes) 


static int __init fail_make_request_debugfs(void)

{

	return init_fault_attr_dentries(&fail_make_request,

					"fail_make_request");

	struct dentry *dir = fault_create_debugfs_attr("fail_make_request",

						NULL, &fail_make_request);



	return IS_ERR(dir) ? PTR_ERR(dir) : 0;

}



late_initcall(fail_make_request_debugfs);

block/blk-timeout.c

+4 −1
Original line number Diff line number Diff line
@@ -28,7 +28,10 @@ int blk_should_fake_timeout(struct request_queue *q) 


static int __init fail_io_timeout_debugfs(void)

{

	return init_fault_attr_dentries(&fail_io_timeout, "fail_io_timeout");

	struct dentry *dir = fault_create_debugfs_attr("fail_io_timeout",

						NULL, &fail_io_timeout);



	return IS_ERR(dir) ? PTR_ERR(dir) : 0;

}



late_initcall(fail_io_timeout_debugfs);

include/linux/fault-inject.h

+5 −13
Original line number Diff line number Diff line
@@ -25,10 +25,6 @@ struct fault_attr { 
	unsigned long reject_end;



	unsigned long count;



#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS

	struct dentry *dir;

#endif

};



#define FAULT_ATTR_INITIALIZER {				\
@@ -45,19 +41,15 @@ bool should_fail(struct fault_attr *attr, ssize_t size); 


#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS



int init_fault_attr_dentries(struct fault_attr *attr, const char *name);

void cleanup_fault_attr_dentries(struct fault_attr *attr);

struct dentry *fault_create_debugfs_attr(const char *name,

			struct dentry *parent, struct fault_attr *attr);



#else /* CONFIG_FAULT_INJECTION_DEBUG_FS */



static inline int init_fault_attr_dentries(struct fault_attr *attr,

					  const char *name)

{

	return -ENODEV;

}



static inline void cleanup_fault_attr_dentries(struct fault_attr *attr)

static inline struct dentry *fault_create_debugfs_attr(const char *name,

			struct dentry *parent, struct fault_attr *attr)

{

	return ERR_PTR(-ENODEV);

}



#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */

lib/fault-inject.c

+7 −13
Original line number Diff line number Diff line
@@ -197,21 +197,15 @@ static struct dentry *debugfs_create_atomic_t(const char *name, mode_t mode, 
	return debugfs_create_file(name, mode, parent, value, &fops_atomic_t);

}



void cleanup_fault_attr_dentries(struct fault_attr *attr)

{

	debugfs_remove_recursive(attr->dir);

}



int init_fault_attr_dentries(struct fault_attr *attr, const char *name)

struct dentry *fault_create_debugfs_attr(const char *name,

			struct dentry *parent, struct fault_attr *attr)

{

	mode_t mode = S_IFREG | S_IRUSR | S_IWUSR;

	struct dentry *dir;



	dir = debugfs_create_dir(name, NULL);

	dir = debugfs_create_dir(name, parent);

	if (!dir)

		return -ENOMEM;



	attr->dir = dir;

		return ERR_PTR(-ENOMEM);



	if (!debugfs_create_ul("probability", mode, dir, &attr->probability))

		goto fail;
@@ -243,11 +237,11 @@ int init_fault_attr_dentries(struct fault_attr *attr, const char *name) 


#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */



	return 0;

	return dir;

fail:

	debugfs_remove_recursive(attr->dir);

	debugfs_remove_recursive(dir);



	return -ENOMEM;

	return ERR_PTR(-ENOMEM);

}



#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */