Messages in this thread Patch in this message |  | | From | Jakob Koschel <> | Subject | [PATCH v2 1/4] tracing: Remove usage of list iterator after the loop body | Date | Sat, 2 Apr 2022 12:33:38 +0200 |
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In preparation to limit the scope of the list iterator variable to the traversal loop, use a dedicated pointer to point to the found element [1].
Before, the code implicitly used the head when no element was found when using &pos->list. Since the new variable is only set if an element was found, the head needs to be used explicitly if the variable is NULL.
Link: https://lore.kernel.org/all/CAHk-=wgRr_D8CB-D9Kg-c=EHreAsk5SqXPwr9Y7k9sA6cWXJ6w@mail.gmail.com/ [1] Signed-off-by: Jakob Koschel <jakobkoschel@gmail.com> --- kernel/trace/trace_output.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c index 8aa493d25c73..733a4d6c20e2 100644 --- a/kernel/trace/trace_output.c +++ b/kernel/trace/trace_output.c @@ -692,7 +692,7 @@ static LIST_HEAD(ftrace_event_list); static int trace_search_list(struct list_head **list) { - struct trace_event *e; + struct trace_event *e = NULL, *iter; int next = __TRACE_LAST_TYPE; if (list_empty(&ftrace_event_list)) { @@ -704,9 +704,11 @@ static int trace_search_list(struct list_head **list) * We used up all possible max events, * lets see if somebody freed one. */ - list_for_each_entry(e, &ftrace_event_list, list) { - if (e->type != next) + list_for_each_entry(iter, &ftrace_event_list, list) { + if (iter->type != next) { + e = iter; break; + } next++; } @@ -714,7 +716,10 @@ static int trace_search_list(struct list_head **list) if (next > TRACE_EVENT_TYPE_MAX) return 0; - *list = &e->list; + if (e) + *list = &e->list; + else + *list = &ftrace_event_list; return next; } -- 2.25.1
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