IB/qib: Add per-context stats interface

This patch adds a debugfs stats interface for per kernel contexts
packet counts.

The code uses the opcode stats count and eliminates the counter in the
context.

Reviewed-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/hw/qib/qib_debugfs.c

@@ -126,6 +126,68 @@ static int _opcode_stats_seq_show(struct seq_file *s, void *v)
 
 DEBUGFS_FILE(opcode_stats)
 
+static void *_ctx_stats_seq_start(struct seq_file *s, loff_t *pos)
+{
+	struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
+	struct qib_devdata *dd = dd_from_dev(ibd);
+
+	if (!*pos)
+		return SEQ_START_TOKEN;
+	if (*pos >= dd->first_user_ctxt)
+		return NULL;
+	return pos;
+}
+
+static void *_ctx_stats_seq_next(struct seq_file *s, void *v, loff_t *pos)
+{
+	struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
+	struct qib_devdata *dd = dd_from_dev(ibd);
+
+	if (v == SEQ_START_TOKEN)
+		return pos;
+
+	++*pos;
+	if (*pos >= dd->first_user_ctxt)
+		return NULL;
+	return pos;
+}
+
+static void _ctx_stats_seq_stop(struct seq_file *s, void *v)
+{
+	/* nothing allocated */
+}
+
+static int _ctx_stats_seq_show(struct seq_file *s, void *v)
+{
+	loff_t *spos;
+	loff_t i, j;
+	u64 n_packets = 0;
+	struct qib_ibdev *ibd = (struct qib_ibdev *)s->private;
+	struct qib_devdata *dd = dd_from_dev(ibd);
+
+	if (v == SEQ_START_TOKEN) {
+		seq_puts(s, "Ctx:npkts\n");
+		return 0;
+	}
+
+	spos = v;
+	i = *spos;
+
+	if (!dd->rcd[i])
+		return SEQ_SKIP;
+
+	for (j = 0; j < ARRAY_SIZE(dd->rcd[i]->opstats->stats); j++)
+		n_packets += dd->rcd[i]->opstats->stats[j].n_packets;
+
+	if (!n_packets)
+		return SEQ_SKIP;
+
+	seq_printf(s, "  %llu:%llu\n", i, n_packets);
+	return 0;
+}
+
+DEBUGFS_FILE(ctx_stats)
+
 void qib_dbg_ibdev_init(struct qib_ibdev *ibd)
 {
 	char name[10];
@@ -137,6 +199,7 @@ void qib_dbg_ibdev_init(struct qib_ibdev *ibd)
 		return;
 	}
 	DEBUGFS_FILE_CREATE(opcode_stats);
+	DEBUGFS_FILE_CREATE(ctx_stats);
 	return;
 }