Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
---
kernel/trace/blktrace.c | 120 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 120 insertions(+)
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 0ed4ce410ed8..5103b79bce2a 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -461,6 +461,126 @@ static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
local_irq_restore(flags);
}
+/*
+ * Data direction bit lookup
+ */
+static const u64 ddir_act_ext[2] = { BLK_TC_ACT_EXT(BLK_TC_READ),
+ BLK_TC_ACT_EXT(BLK_TC_WRITE) };
+
+/* The ilog2() calls fall out because they're constant */
+#define MASK_TC_BIT_EXT(rw, __name) ((rw & REQ_ ## __name) << \
+ (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT_EXT - __REQ_ ## __name))
+
+/*
+ * The worker for the various blk_add_trace*() types. Fills out a
+ * blk_io_trace structure and places it in a per-cpu subbuffer.
+ */
+static void __blk_add_trace_ext(struct blk_trace_ext *bt, sector_t sector, int bytes,
+ int op, int op_flags, u64 what, int error, int pdu_len,
+ void *pdu_data, union kernfs_node_id *cgid, u32 ioprio)
+{
+ struct task_struct *tsk = current;
+ struct ring_buffer_event *event = NULL;
+ struct ring_buffer *buffer = NULL;
+ struct blk_io_trace_ext *t;
+ unsigned long flags = 0;
+ unsigned long *sequence;
+ pid_t pid;
+ int cpu, pc = 0;
+ bool blk_tracer = blk_tracer_enabled;
+ ssize_t cgid_len = cgid ? sizeof(*cgid) : 0;
+
+ if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
+ return;
+
+ what |= ddir_act_ext[op_is_write(op) ? WRITE : READ];
+ what |= MASK_TC_BIT_EXT(op_flags, SYNC);
+ what |= MASK_TC_BIT_EXT(op_flags, RAHEAD);
+ what |= MASK_TC_BIT_EXT(op_flags, META);
+ what |= MASK_TC_BIT_EXT(op_flags, PREFLUSH);
+ what |= MASK_TC_BIT_EXT(op_flags, FUA);
+ if (op == REQ_OP_DISCARD || op == REQ_OP_SECURE_ERASE)
+ what |= BLK_TC_ACT_EXT(BLK_TC_DISCARD);
+ if (op == REQ_OP_FLUSH)
+ what |= BLK_TC_ACT_EXT(BLK_TC_FLUSH);
+ if (unlikely(op == REQ_OP_WRITE_ZEROES))
+ what |= BLK_TC_ACT_EXT(BLK_TC_WRITE_ZEROES);
+ if (unlikely(op == REQ_OP_ZONE_RESET))
+ what |= BLK_TC_ACT_EXT(BLK_TC_ZONE_RESET);
+
+ if (cgid)
+ what |= __BLK_TA_CGROUP;
+
+ pid = tsk->pid;
+ if (act_log_check_ext(bt, what, sector, pid))
+ return;
+ if (bt->prio_mask && !prio_log_check(bt, ioprio))
+ return;
+
+ cpu = raw_smp_processor_id();
+
+ if (blk_tracer) {
+ tracing_record_cmdline(current);
+
+ buffer = blk_tr->trace_buffer.buffer;
+ pc = preempt_count();
+ event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
+ sizeof(*t) + pdu_len + cgid_len,
+ 0, pc);
+ if (!event)
+ return;
+ t = ring_buffer_event_data(event);
+ goto record_it;
+ }
+
+ if (unlikely(tsk->btrace_seq != blktrace_seq))
+ trace_note_tsk_ext(tsk, ioprio);
+
+ /*
+ * A word about the locking here - we disable interrupts to reserve
+ * some space in the relay per-cpu buffer, to prevent an irq
+ * from coming in and stepping on our toes.
+ */
+ local_irq_save(flags);
+ t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len + cgid_len);
+ if (t) {
+ sequence = per_cpu_ptr(bt->sequence, cpu);
+
+ t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION_EXT;
+ t->sequence = ++(*sequence);
+ t->time = ktime_to_ns(ktime_get());
+record_it:
+ /*
+ * These two are not needed in ftrace as they are in the
+ * generic trace_entry, filled by tracing_generic_entry_update,
+ * but for the trace_event->bin() synthesizer benefit we do it
+ * here too.
+ */
+ t->cpu = cpu;
+ t->pid = pid;
+
+ t->sector = sector;
+ t->bytes = bytes;
+ t->action = what;
+ t->ioprio = ioprio;
+ t->device = bt->dev;
+ t->error = error;
+ t->pdu_len = pdu_len + cgid_len;
+
+ if (cgid_len)
+ memcpy((void *)t + sizeof(*t), cgid, cgid_len);
+ if (pdu_len)
+ memcpy((void *)t + sizeof(*t) + cgid_len, pdu_data, pdu_len);
+
+ if (blk_tracer) {
+ trace_buffer_unlock_commit(blk_tr, buffer, event, 0, pc);
+ return;
+ }
+ }
+
+ local_irq_restore(flags);
+}
+
static void blk_trace_free(struct blk_trace *bt)
{
debugfs_remove(bt->msg_file);
--
2.19.1
