module: Fix up module_notifier return values
While auditing all module notifiers I noticed a whole bunch of fail
wrt the return value. Notifiers have a 'special' return semantics.
As is; NOTIFY_DONE vs NOTIFY_OK is a bit vague; but
notifier_from_errno(0) results in NOTIFY_OK and NOTIFY_DONE has a
comment that says "Don't care".
From this I've used NOTIFY_DONE when the function completely ignores
the callback and notifier_to_error() isn't used.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: Robert Richter <rric@kernel.org>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20200818135804.385360407@infradead.org
diff --git a/drivers/oprofile/buffer_sync.c b/drivers/oprofile/buffer_sync.c
index 4d76952..cc91786 100644
--- a/drivers/oprofile/buffer_sync.c
+++ b/drivers/oprofile/buffer_sync.c
@@ -116,7 +116,7 @@ module_load_notify(struct notifier_block *self, unsigned long val, void *data)
{
#ifdef CONFIG_MODULES
if (val != MODULE_STATE_COMING)
- return 0;
+ return NOTIFY_DONE;
/* FIXME: should we process all CPU buffers ? */
mutex_lock(&buffer_mutex);
@@ -124,7 +124,7 @@ module_load_notify(struct notifier_block *self, unsigned long val, void *data)
add_event_entry(MODULE_LOADED_CODE);
mutex_unlock(&buffer_mutex);
#endif
- return 0;
+ return NOTIFY_OK;
}
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index a8d4f25..2ecf789 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2027,10 +2027,11 @@ static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
{
struct bpf_trace_module *btm, *tmp;
struct module *mod = module;
+ int ret = 0;
if (mod->num_bpf_raw_events == 0 ||
(op != MODULE_STATE_COMING && op != MODULE_STATE_GOING))
- return 0;
+ goto out;
mutex_lock(&bpf_module_mutex);
@@ -2040,6 +2041,8 @@ static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
if (btm) {
btm->module = module;
list_add(&btm->list, &bpf_trace_modules);
+ } else {
+ ret = -ENOMEM;
}
break;
case MODULE_STATE_GOING:
@@ -2055,7 +2058,8 @@ static int bpf_event_notify(struct notifier_block *nb, unsigned long op,
mutex_unlock(&bpf_module_mutex);
- return 0;
+out:
+ return notifier_from_errno(ret);
}
static struct notifier_block bpf_module_nb = {
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f40d850..df49992 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -9072,7 +9072,7 @@ static int trace_module_notify(struct notifier_block *self,
break;
}
- return 0;
+ return NOTIFY_OK;
}
static struct notifier_block trace_module_nb = {
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index a85effb..beebf2c 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2646,7 +2646,7 @@ static int trace_module_notify(struct notifier_block *self,
mutex_unlock(&trace_types_lock);
mutex_unlock(&event_mutex);
- return 0;
+ return NOTIFY_OK;
}
static struct notifier_block trace_module_nb = {
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
index d4e31e9..bb7783b 100644
--- a/kernel/trace/trace_printk.c
+++ b/kernel/trace/trace_printk.c
@@ -96,7 +96,7 @@ static int module_trace_bprintk_format_notify(struct notifier_block *self,
if (val == MODULE_STATE_COMING)
hold_module_trace_bprintk_format(start, end);
}
- return 0;
+ return NOTIFY_OK;
}
/*
@@ -174,7 +174,7 @@ __init static int
module_trace_bprintk_format_notify(struct notifier_block *self,
unsigned long val, void *data)
{
- return 0;
+ return NOTIFY_OK;
}
static inline const char **
find_next_mod_format(int start_index, void *v, const char **fmt, loff_t *pos)
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index 73956ea..8e05ed2 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -521,7 +521,7 @@ static int tracepoint_module_notify(struct notifier_block *self,
case MODULE_STATE_UNFORMED:
break;
}
- return ret;
+ return notifier_from_errno(ret);
}
static struct notifier_block tracepoint_module_nb = {
