[ethtool,4/6] ethtool: support per-queue sub command --show-coalesce

diff --git a/ethtool.8.in b/ethtool.8.in
index 0aaca2c..71bb962 100644
--- a/ethtool.8.in
+++ b/ethtool.8.in
@@ -1153,7 +1153,7 @@  Sets the specific queues which the sub command is applied to.
 If queue_mask is not set, the sub command will be applied to all queues.
 .TP
 .B sub_command
-Sets the sub command.
+Sets the sub command. The supported sub commands include --show-coalesce.
 .RE
 .SH BUGS
 Not supported (in part or whole) on all network drivers.
diff --git a/ethtool.c b/ethtool.c
index e089981..c7a12d7 100644
--- a/ethtool.c
+++ b/ethtool.c
@@ -1409,6 +1409,29 @@  static int dump_coalesce(const struct ethtool_coalesce *ecoal)
 	return 0;
 }
 
+void dump_per_queue_coalesce(struct ethtool_per_queue_op *per_queue_opt,
+			     __u32 *queue_mask)
+{
+	char *addr;
+	int i;
+
+	addr = (char *)per_queue_opt + sizeof(*per_queue_opt);
+	for (i = 0; i < __KERNEL_DIV_ROUND_UP(MAX_NUM_QUEUE, 32); i++) {
+		int queue = i * 32;
+		__u32 mask = queue_mask[i];
+
+		while (mask > 0) {
+			if (mask & 0x1) {
+				fprintf(stdout, "Queue: %d\n", queue);
+				dump_coalesce((struct ethtool_coalesce *)addr);
+				addr += sizeof(struct ethtool_coalesce);
+			}
+			mask = mask >> 1;
+			queue++;
+		}
+	}
+}
+
 struct feature_state {
 	u32 off_flags;
 	struct ethtool_gfeatures features;
@@ -5245,7 +5268,8 @@  static const struct option {
 	{ "--show-fec", 1, do_gfec, "Show FEC settings"},
 	{ "--set-fec", 1, do_sfec, "Set FEC settings",
 	  "		[ encoding auto|off|rs|baser [...]]\n"},
-	{ "--set-perqueue-command", 1, do_perqueue, "Set per queue command",
+	{ "--set-perqueue-command", 1, do_perqueue, "Set per queue command. "
+	  "The supported sub commands include --show-coalesce",
 	  "             [queue_mask %x] SUB_COMMAND\n"},
 	{ "-h|--help", 0, show_usage, "Show this help" },
 	{ "--version", 0, do_version, "Show version number" },
@@ -5350,8 +5374,32 @@  static int find_max_num_queues(struct cmd_context *ctx)
 		   echannels.combined_count);
 }
 
+static struct ethtool_per_queue_op *
+get_per_queue_coalesce(struct cmd_context *ctx, __u32 *queue_mask, int n_queues)
+{
+	struct ethtool_per_queue_op *per_queue_opt;
+
+	per_queue_opt = malloc(sizeof(*per_queue_opt) + n_queues *
+			sizeof(struct ethtool_coalesce));
+	if (!per_queue_opt)
+		return NULL;
+
+	memcpy(per_queue_opt->queue_mask, queue_mask,
+	       __KERNEL_DIV_ROUND_UP(MAX_NUM_QUEUE, 32) * sizeof(__u32));
+	per_queue_opt->cmd = ETHTOOL_PERQUEUE;
+	per_queue_opt->sub_command = ETHTOOL_GCOALESCE;
+	if (send_ioctl(ctx, per_queue_opt)) {
+		free(per_queue_opt);
+		perror("Cannot get device per queue parameters");
+		return NULL;
+	}
+
+	return per_queue_opt;
+}
+
 static int do_perqueue(struct cmd_context *ctx)
 {
+	struct ethtool_per_queue_op *per_queue_opt;
 	__u32 queue_mask[__KERNEL_DIV_ROUND_UP(MAX_NUM_QUEUE, 32)] = {0};
 	int i, n_queues = 0;
 
@@ -5390,7 +5438,19 @@  static int do_perqueue(struct cmd_context *ctx)
 	if (i < 0)
 		exit_bad_args();
 
-	/* no sub_command support yet */
+	if (strstr(args[i].opts, "--show-coalesce") != NULL) {
+		per_queue_opt = get_per_queue_coalesce(ctx, queue_mask,
+						       n_queues);
+		if (per_queue_opt == NULL) {
+			perror("Cannot get device per queue parameters");
+			return -EFAULT;
+		}
+		dump_per_queue_coalesce(per_queue_opt, queue_mask);
+		free(per_queue_opt);
+	} else {
+		perror("The subcommand is not supported yet");
+		return -EOPNOTSUPP;
+	}
 
 	return 0;
 }