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: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Per 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 13 deletions

diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
index 3ff060ac7810..c6f996f2abb6 100644
--- a/include/linux/fault-inject.h
+++ b/include/linux/fault-inject.h
@@ -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 */