[PATCH] ndctl/bus:Handling the scrub related command more gracefully

[Tarun Sahu <tsahu@linux.ibm.com>]

For the buses, that don't have nfit support, they use to
return "No such file or directory" for start-scrub/
wait-scrub command.

Though, non-nfit support buses do not support start-scrub/
wait-scrub operation. I propose this patch to handle these
commands more gracefully by returning "Operation not
supported".

Previously:
$ ./ndctl start-scrub ndbus0
error starting scrub: No such file or directory

Now:
$ ./ndctl start-scrub ndbus0
error starting scrub: Operation not supported

Signed-off-by: Tarun Sahu <tsahu@linux.ibm.com>
---
 ndctl/lib/libndctl.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/ndctl/lib/libndctl.c b/ndctl/lib/libndctl.c
index ccca8b5..8bfad6a 100644
--- a/ndctl/lib/libndctl.c
+++ b/ndctl/lib/libndctl.c
@@ -938,10 +938,14 @@ static void *add_bus(void *parent, int id, const char *ctl_base)
 	if (!bus->wait_probe_path)
 		goto err_read;
 
-	sprintf(path, "%s/device/nfit/scrub", ctl_base);
-	bus->scrub_path = strdup(path);
-	if (!bus->scrub_path)
-		goto err_read;
+	if (ndctl_bus_has_nfit(bus)) {
+		sprintf(path, "%s/device/nfit/scrub", ctl_base);
+		bus->scrub_path = strdup(path);
+		if (!bus->scrub_path)
+			goto err_read;
+	} else {
+		bus->scrub_path = NULL;
+	}
 
 	sprintf(path, "%s/device/firmware/activate", ctl_base);
 	if (sysfs_read_attr(ctx, path, buf) < 0)
@@ -1377,6 +1381,9 @@ NDCTL_EXPORT int ndctl_bus_start_scrub(struct ndctl_bus *bus)
 	struct ndctl_ctx *ctx = ndctl_bus_get_ctx(bus);
 	int rc;
 
+	if (bus->scrub_path == NULL)
+		return -EOPNOTSUPP;
+
 	rc = sysfs_write_attr(ctx, bus->scrub_path, "1\n");
 
 	/*
@@ -1447,6 +1454,9 @@ NDCTL_EXPORT int ndctl_bus_poll_scrub_completion(struct ndctl_bus *bus,
 	char in_progress;
 	int fd = 0, rc;
 
+	if (bus->scrub_path == NULL)
+		return -EOPNOTSUPP;
+
 	fd = open(bus->scrub_path, O_RDONLY|O_CLOEXEC);
 	if (fd < 0)
 		return -errno;
-- 
2.35.1