From: Hannes Reinecke <hare@suse.de>
Date: Mon, 20 Dec 2021 13:51:45 +0100
Subject: nvme: add 'iopolicy' module parameter
Patch-mainline: v5.17-rc1
Git-commit: e3d347943919f35ccdeed8d2cc62e8c6c12b36cd
References: bsc#1177599 bsc#1193096
While the 'iopolicy' sysfs attribute can be set at runtime, most
storage arrays prefer to use the 'round-robin' iopolicy per default.
We can use udev rules to set this, but is getting rather unwieldy
for rebranded arrays as we would have to update the udev rules
anytime a new array shows up, leading to the same mess we currently
have in multipathd for configuring the RDAC arrays.
Hence this patch adds a module parameter 'iopolicy' to allow the
admin to switch the default, and to do away with the need for a
udev rule here.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Daniel Wagner <dwagner@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
drivers/nvme/host/core.c | 4 +---
drivers/nvme/host/multipath.c | 41 ++++++++++++++++++++++++++++++++++++-----
drivers/nvme/host/nvme.h | 4 ++++
3 files changed, 41 insertions(+), 8 deletions(-)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2388,9 +2388,7 @@ static int nvme_init_subsystem(struct nv
memcpy(subsys->firmware_rev, id->fr, sizeof(subsys->firmware_rev));
subsys->vendor_id = le16_to_cpu(id->vid);
subsys->cmic = id->cmic;
-#ifdef CONFIG_NVME_MULTIPATH
- subsys->iopolicy = NVME_IOPOLICY_NUMA;
-#endif
+ nvme_mpath_default_iopolicy(subsys);
subsys->dev.class = nvme_subsys_class;
subsys->dev.release = nvme_release_subsystem;
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -20,6 +20,42 @@ module_param(multipath, bool, 0444);
MODULE_PARM_DESC(multipath,
"turn on native support for multiple controllers per subsystem");
+static const char *nvme_iopolicy_names[] = {
+ [NVME_IOPOLICY_NUMA] = "numa",
+ [NVME_IOPOLICY_RR] = "round-robin",
+};
+
+static int iopolicy = NVME_IOPOLICY_NUMA;
+
+static int nvme_set_iopolicy(const char *val, struct kernel_param *kp)
+{
+ if (!val)
+ return -EINVAL;
+ if (!strncmp(val, "numa", 4))
+ iopolicy = NVME_IOPOLICY_NUMA;
+ else if (!strncmp(val, "round-robin", 11))
+ iopolicy = NVME_IOPOLICY_RR;
+ else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int nvme_get_iopolicy(char *buf, struct kernel_param *kp)
+{
+ return sprintf(buf, "%s\n", nvme_iopolicy_names[iopolicy]);
+}
+
+module_param_call(iopolicy, nvme_set_iopolicy, nvme_get_iopolicy,
+ &iopolicy, 0644);
+MODULE_PARM_DESC(iopolicy,
+ "Default multipath I/O policy; 'numa' (default) or 'round-robin'");
+
+void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys)
+{
+ subsys->iopolicy = iopolicy;
+}
+
void nvme_mpath_unfreeze(struct nvme_subsystem *subsys)
{
struct nvme_ns_head *h;
@@ -630,11 +666,6 @@ void nvme_mpath_stop(struct nvme_ctrl *c
struct device_attribute subsys_attr_##_name = \
__ATTR(_name, _mode, _show, _store)
-static const char *nvme_iopolicy_names[] = {
- [NVME_IOPOLICY_NUMA] = "numa",
- [NVME_IOPOLICY_RR] = "round-robin",
-};
-
static ssize_t nvme_subsys_iopolicy_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -495,6 +495,7 @@ static inline bool nvme_ctrl_use_ana(str
void nvme_mpath_unfreeze(struct nvme_subsystem *subsys);
void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys);
void nvme_mpath_start_freeze(struct nvme_subsystem *subsys);
+void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys);
void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
struct nvme_ctrl *ctrl, int *flags);
bool nvme_failover_req(struct request *req);
@@ -602,6 +603,9 @@ static inline void nvme_mpath_start_free
static inline void nvme_mpath_update_disk_size(struct gendisk *disk)
{
}
+static inline void nvme_mpath_default_iopolicy(struct nvme_subsystem *subsys)
+{
+}
#endif /* CONFIG_NVME_MULTIPATH */
#ifdef CONFIG_NVM