From: Tom Zanussi Up until now, hist triggers only needed per-element support for saving 'comm' data, which was saved directly as a private data pointer. In anticipation of the need to save other data besides 'comm', add a new hist_elt_data struct for the purpose, and switch the current 'comm'-related code over to that. Link: http://lkml.kernel.org/r/4502c338c965ddf5fc19fb1ec4764391e001ed4b.1516069914.git.tom.zanussi@linux.intel.com Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_events_hist.c | 76 +++++++++++++++++++++++----------------- 1 file changed, 43 insertions(+), 33 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 4c3c7d784bfd..f072ed3122c8 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -289,6 +289,10 @@ static struct hist_field *find_var(struct hist_trigger_data *hist_data, return NULL; } +struct hist_elt_data { + char *comm; +}; + static const char *hist_field_name(struct hist_field *field, unsigned int level) { @@ -503,45 +507,61 @@ static inline void save_comm(char *comm, struct task_struct *task) memcpy(comm, task->comm, TASK_COMM_LEN); } -static void hist_trigger_elt_comm_free(struct tracing_map_elt *elt) +static void hist_elt_data_free(struct hist_elt_data *elt_data) +{ + kfree(elt_data->comm); + kfree(elt_data); +} + +static void hist_trigger_elt_data_free(struct tracing_map_elt *elt) { - kfree((char *)elt->private_data); + struct hist_elt_data *elt_data = elt->private_data; + + hist_elt_data_free(elt_data); } -static int hist_trigger_elt_comm_alloc(struct tracing_map_elt *elt) +static int hist_trigger_elt_data_alloc(struct tracing_map_elt *elt) { struct hist_trigger_data *hist_data = elt->map->private_data; + unsigned int size = TASK_COMM_LEN; + struct hist_elt_data *elt_data; struct hist_field *key_field; unsigned int i; + elt_data = kzalloc(sizeof(*elt_data), GFP_KERNEL); + if (!elt_data) + return -ENOMEM; + for_each_hist_key_field(i, hist_data) { key_field = hist_data->fields[i]; if (key_field->flags & HIST_FIELD_FL_EXECNAME) { - unsigned int size = TASK_COMM_LEN + 1; - - elt->private_data = kzalloc(size, GFP_KERNEL); - if (!elt->private_data) + elt_data->comm = kzalloc(size, GFP_KERNEL); + if (!elt_data->comm) { + kfree(elt_data); return -ENOMEM; + } break; } } + elt->private_data = elt_data; + return 0; } -static void hist_trigger_elt_comm_init(struct tracing_map_elt *elt) +static void hist_trigger_elt_data_init(struct tracing_map_elt *elt) { - char *comm = elt->private_data; + struct hist_elt_data *elt_data = elt->private_data; - if (comm) - save_comm(comm, current); + if (elt_data->comm) + save_comm(elt_data->comm, current); } -static const struct tracing_map_ops hist_trigger_elt_comm_ops = { - .elt_alloc = hist_trigger_elt_comm_alloc, - .elt_free = hist_trigger_elt_comm_free, - .elt_init = hist_trigger_elt_comm_init, +static const struct tracing_map_ops hist_trigger_elt_data_ops = { + .elt_alloc = hist_trigger_elt_data_alloc, + .elt_free = hist_trigger_elt_data_free, + .elt_init = hist_trigger_elt_data_init, }; static const char *get_hist_field_flags(struct hist_field *hist_field) @@ -1484,21 +1504,6 @@ static int create_tracing_map_fields(struct hist_trigger_data *hist_data) return 0; } -static bool need_tracing_map_ops(struct hist_trigger_data *hist_data) -{ - struct hist_field *key_field; - unsigned int i; - - for_each_hist_key_field(i, hist_data) { - key_field = hist_data->fields[i]; - - if (key_field->flags & HIST_FIELD_FL_EXECNAME) - return true; - } - - return false; -} - static struct hist_trigger_data * create_hist_data(unsigned int map_bits, struct hist_trigger_attrs *attrs, @@ -1524,8 +1529,7 @@ create_hist_data(unsigned int map_bits, if (ret) goto free; - if (need_tracing_map_ops(hist_data)) - map_ops = &hist_trigger_elt_comm_ops; + map_ops = &hist_trigger_elt_data_ops; hist_data->map = tracing_map_create(map_bits, hist_data->key_size, map_ops, hist_data); @@ -1713,7 +1717,13 @@ hist_trigger_entry_print(struct seq_file *m, seq_printf(m, "%s: [%llx] %-55s", field_name, uval, str); } else if (key_field->flags & HIST_FIELD_FL_EXECNAME) { - char *comm = elt->private_data; + struct hist_elt_data *elt_data = elt->private_data; + char *comm; + + if (WARN_ON_ONCE(!elt_data)) + return; + + comm = elt_data->comm; uval = *(u64 *)(key + key_field->offset); seq_printf(m, "%s: %-16s[%10llu]", field_name, -- 2.15.1