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

[Bart Van Assche]

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.vanass...@wdc.com>
Cc: Dmitry Vyukov <dvyu...@google.com>
Cc: Akinobu Mita <akinobu.m...@gmail.com>
Cc: Michal Hocko <mho...@kernel.org>
Cc: Andrew Morton <a...@linux-foundation.org>
---
 include/linux/fault-inject.h | 9 +++++++--
 lib/fault-inject.c           | 4 +++-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/include/linux/fault-inject.h b/include/linux/fault-inject.h
index 728d4e0292aa..8851646d2698 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 +31,21 @@ 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 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