From b9b16d5170f23433a30cb88eefd2ab30b48d151e Mon Sep 17 00:00:00 2001
From: Yair Elharrar <yair@excelero.com>
Date: Thu, 23 Jan 2020 14:16:39 +0200
Subject: [PATCH] list-subsys: when running on old kernels, get PCIe B:D.f
 address from sysfs

Signed-off-by: Yair Elharrar <yair@excelero.com>
---
 nvme-topology.c | 59 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/nvme-topology.c b/nvme-topology.c
index 4317939..55ad8c1 100644
--- a/nvme-topology.c
+++ b/nvme-topology.c
@@ -89,6 +89,56 @@ err_free_path:
 	return NULL;
 }
 
+static char *path_trim_last(char *path, char needle)
+{
+	int i;
+	i = strlen(path);
+	if (i>0 && path[i-1] == needle)		// remove trailing slash
+		path[--i] = 0;
+	for (; i>0; i--)
+		if (path[i] == needle) {
+			path[i] = 0;
+			return path+i+1;
+	}
+	return NULL;
+}
+
+static void legacy_get_pci_bdf(char *node, char *bdf)
+{
+	int ret;
+	char path[264], nodetmp[264];
+	struct stat st;
+	char *p, *__path = path;
+
+	bdf[0] = 0;
+	strcpy(nodetmp, node);
+	p = path_trim_last(nodetmp, '/');
+	sprintf(path, "/sys/block/%s/device", p);
+	ret = readlink(path, nodetmp, sizeof(nodetmp));
+	if (ret <= 0)
+		return;
+	nodetmp[ret] = 0;
+	/* The link value is either "device -> ../../../0000:86:00.0" or "device -> ../../nvme0" */
+	(void) path_trim_last(path, '/');
+	sprintf(path+strlen(path), "/%s/device", nodetmp);
+	ret = stat(path, &st);
+	if (ret < 0)
+		return;
+	if ((st.st_mode & S_IFLNK) == 0) {
+		/* follow the second link to get the PCI address */
+		ret = readlink(path, __path, sizeof(path));
+		if (ret <= 0)
+			return;
+		path[ret] = 0;
+	}
+	else
+		(void) path_trim_last(path, '/');
+
+	p = path_trim_last(path, '/');
+	if (p && strlen(p) == 12)
+		strcpy(bdf, p);
+}
+
 static int scan_namespace(struct nvme_namespace *n)
 {
 	int ret, fd;
@@ -303,6 +353,15 @@ static int verify_legacy_ns(struct nvme_namespace *n)
 	if (ret < 0)
 		return ret;
 
+	if (!n->ctrl->transport && !n->ctrl->address) {
+		char tmp_address[64] = "";
+		legacy_get_pci_bdf(path, tmp_address);
+		if (tmp_address[0]) {
+			asprintf(&n->ctrl->transport, "pcie");
+			asprintf(&n->ctrl->address, tmp_address);
+		}
+	}
+
 	fd = open(path, O_RDONLY);
 	free (path);
 
-- 
2.49.0