Hello Takashi Sakamoto,
The patch fef4e61b0b76: "ALSA: firewire-lib: extend tracepoints event
including CYCLE_TIME of 1394 OHCI" from Jan 10, 2023, leads to the
following Smatch static checker warning:
sound/firewire/amdtp-stream.c:944 generate_tx_packet_descs() error: uninitialized symbol 'curr_cycle_time'.
sound/firewire/amdtp-stream.c:1099 process_rx_packets() error: uninitialized symbol 'curr_cycle_time'.
sound/firewire/amdtp-stream.c
1047 static void process_rx_packets(struct fw_iso_context *context, u32 tstamp, size_t header_length,
1048 void *header, void *private_data)
1049 {
1050 struct amdtp_stream *s = private_data;
1051 const struct amdtp_domain *d = s->domain;
1052 const __be32 *ctx_header = header;
1053 const unsigned int events_per_period = d->events_per_period;
1054 unsigned int event_count = s->ctx_data.rx.event_count;
1055 struct pkt_desc *desc = s->packet_descs_cursor;
1056 unsigned int pkt_header_length;
1057 unsigned int packets;
1058 u32 curr_cycle_time;
^^^^^^^^^^^^^^^^^^^
1059 bool need_hw_irq;
1060 int i;
1061
1062 if (s->packet_index < 0)
1063 return;
1064
1065 // Calculate the number of packets in buffer and check XRUN.
1066 packets = header_length / sizeof(*ctx_header);
1067
1068 generate_rx_packet_descs(s, desc, ctx_header, packets);
1069
1070 process_ctx_payloads(s, desc, packets);
1071
1072 if (!(s->flags & CIP_NO_HEADER))
1073 pkt_header_length = IT_PKT_HEADER_SIZE_CIP;
1074 else
1075 pkt_header_length = 0;
1076
1077 if (s == d->irq_target) {
1078 // At NO_PERIOD_WAKEUP mode, the packets for all IT/IR contexts are processed by
1079 // the tasks of user process operating ALSA PCM character device by calling ioctl(2)
1080 // with some requests, instead of scheduled hardware IRQ of an IT context.
1081 struct snd_pcm_substream *pcm = READ_ONCE(s->pcm);
1082 need_hw_irq = !pcm || !pcm->runtime->no_period_wakeup;
1083 } else {
1084 need_hw_irq = false;
1085 }
1086
1087 if (trace_amdtp_packet_enabled())
1088 (void)fw_card_read_cycle_time(fw_parent_device(s->unit)->card, &curr_cycle_time);
No error checking and no else path.
1089
1090 for (i = 0; i < packets; ++i) {
1091 struct {
1092 struct fw_iso_packet params;
1093 __be32 header[CIP_HEADER_QUADLETS];
1094 } template = { {0}, {0} };
1095 bool sched_irq = false;
1096
1097 build_it_pkt_header(s, desc->cycle, &template.params, pkt_header_length,
1098 desc->data_blocks, desc->data_block_counter,
--> 1099 desc->syt, i, curr_cycle_time);
^^^^^^^^^^^^^^^
Uninitialized.
1100
1101 if (s == s->domain->irq_target) {
1102 event_count += desc->data_blocks;
1103 if (event_count >= events_per_period) {
1104 event_count -= events_per_period;
1105 sched_irq = need_hw_irq;
1106 }
1107 }
1108
1109 if (queue_out_packet(s, &template.params, sched_irq) < 0) {
1110 cancel_stream(s);
1111 return;
1112 }
1113
1114 desc = amdtp_stream_next_packet_desc(s, desc);
1115 }
1116
1117 s->ctx_data.rx.event_count = event_count;
1118 s->packet_descs_cursor = desc;
1119 }
regards,
dan carpenter
