[PATCH v2 1/2] fault-inject: Restore support for task-independent fault injection

[Bart Van Assche <bart.vanassche@wdc.com>]

Certain faults should be injected independent of the context
in which these occur. Commit e41d58185f14 made it impossible to
inject faults independent of their context. Restore support for
task-independent fault injection by adding the attribute 'global'.

References: commit e41d58185f14 ("fault-inject: support systematic fault injection")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 include/linux/fault-inject.h | 11 +++++++++--
 lib/fault-inject.c           |  4 +++-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
index 728d4e0292aa..88dae2f21881 100644
--- a/include/linux/fault-inject.h
+++ b/include/linux/fault-inject.h
@@ -18,6 +18,7 @@ struct fault_attr {
 	atomic_t times;
 	atomic_t space;
 	unsigned long verbose;
+	bool global;
 	bool task_filter;
 	unsigned long stacktrace_depth;
 	unsigned long require_start;
@@ -30,17 +31,23 @@ struct fault_attr {
 	struct dentry *dname;
 };
 
-#define FAULT_ATTR_INITIALIZER {					\
+#define __FAULT_ATTR_INITIALIZER(__global) {				\
 		.interval = 1,						\
 		.times = ATOMIC_INIT(1),				\
 		.require_end = ULONG_MAX,				\
+		.global = (__global),					\
 		.stacktrace_depth = 32,					\
 		.ratelimit_state = RATELIMIT_STATE_INIT_DISABLED,	\
 		.verbose = 2,						\
 		.dname = NULL,						\
 	}
 
-#define DECLARE_FAULT_ATTR(name) struct fault_attr name = FAULT_ATTR_INITIALIZER
+#define FAULT_ATTR_INITIALIZER __FAULT_ATTR_INITIALIZER(false)
+
+#define DECLARE_FAULT_ATTR(name)				\
+	struct fault_attr name = __FAULT_ATTR_INITIALIZER(false)
+#define DECLARE_GLOBAL_FAULT_ATTR(name)				\
+	struct fault_attr name = __FAULT_ATTR_INITIALIZER(true)
 int setup_fault_attr(struct fault_attr *attr, char *str);
 bool should_fail(struct fault_attr *attr, ssize_t size);
 
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
index 7d315fdb9f13..c8f6ef5df3c6 100644
--- a/lib/fault-inject.c
+++ b/lib/fault-inject.c
@@ -107,7 +107,7 @@ static inline bool fail_stacktrace(struct fault_attr *attr)
 
 bool should_fail(struct fault_attr *attr, ssize_t size)
 {
-	if (in_task()) {
+	if (!attr->global && in_task()) {
 		unsigned int fail_nth = READ_ONCE(current->fail_nth);
 
 		if (fail_nth && !WRITE_ONCE(current->fail_nth, fail_nth - 1))
@@ -224,6 +224,8 @@ struct dentry *fault_create_debugfs_attr(const char *name,
 	if (!debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
 				&attr->ratelimit_state.burst))
 		goto fail;
+	if (!debugfs_create_bool("global", mode, dir, &attr->global))
+		goto fail;
 	if (!debugfs_create_bool("task-filter", mode, dir, &attr->task_filter))
 		goto fail;
 
-- 
2.14.0