[PATCH v2 2/3] nvme-multipath: add the NVME_MULTIPATH_PARAM config option

[John Meneghini <jmeneghi@redhat.com>]

The new CONFIG_NVME_MULTIPATH_PARAM option controls the core_nvme.multipath
parameter. When CONFIG_NVME_MULTIPATH_PARAM=n the multipath parameter is
removed from the kernel and nvme multipathing is permanently enabled.
When NVME_MULTIPATH_PARAM=y the nvme multipath parameter is added to the
kernel and nvme multipath support is controlled by the
core_nvme.multipath parameter.

By default CONFIG_NVME_MULTIPATH_PARAM=y

Signed-off-by: John Meneghini <jmeneghi@redhat.com>
Tested-by: John Meneghini <jmeneghi@redhat.com>
Reviewed-by: Bryan Gurney <bgurney@redhat.com>
---
 drivers/nvme/host/Kconfig     | 13 +++++++++++++
 drivers/nvme/host/multipath.c |  3 ++-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/Kconfig b/drivers/nvme/host/Kconfig
index d47dfa80fb95..c8458b10c83f 100644
--- a/drivers/nvme/host/Kconfig
+++ b/drivers/nvme/host/Kconfig
@@ -28,6 +28,19 @@ config NVME_MULTIPATH
 
 	  If unsure, say Y.
 
+config NVME_MULTIPATH_PARAM
+	bool "NVMe multipath param"
+	depends on NVME_CORE && NVME_MULTIPATH
+	default y
+	help
+	  This option controls the inclusion of the NVMe core module
+	  "multipath" parameter. If this option is disabled the
+	  nvme_core.multipath parameter is excluded from the kernel.
+	  If this option is enabled the nvme_core.multipath parameter
+	  is included in the kernel.
+
+	  If unsure, say Y.
+
 config NVME_VERBOSE_ERRORS
 	bool "NVMe verbose error reporting"
 	depends on NVME_CORE
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 6b12ca80aa27..cad76de2830a 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -10,10 +10,11 @@
 #include "nvme.h"
 
 bool multipath = true;
+#ifdef CONFIG_NVME_MULTIPATH_PARAM
 module_param(multipath, bool, 0444);
 MODULE_PARM_DESC(multipath,
 	"turn on native support for multiple controllers per subsystem");
-
+#endif
 static const char *nvme_iopolicy_names[] = {
 	[NVME_IOPOLICY_NUMA]	= "numa",
 	[NVME_IOPOLICY_RR]	= "round-robin",
-- 
2.48.1