We are converting tcmu applications to ublk, but have systems with up
to 1k devices. This patch allows us to configure the ublks_max from
userspace with the ublks_max modparam.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
---
drivers/block/ublk_drv.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 18e352f8cd6d..2833a81e05c0 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -2940,7 +2940,36 @@ static void __exit ublk_exit(void)
module_init(ublk_init);
module_exit(ublk_exit);
-module_param(ublks_max, int, 0444);
+static int ublk_set_max_ublks(const char *buf, const struct kernel_param *kp)
+{
+ unsigned int max;
+ int ret;
+
+ ret = kstrtouint(buf, 10, &max);
+ if (ret)
+ return ret;
+
+ if (max > UBLK_MAX_UBLKS) {
+ pr_warn("Invalid ublks_max. Max supported is %d\n",
+ UBLK_MAX_UBLKS);
+ return -EINVAL;
+ }
+
+ ublks_max = max;
+ return ret;
+}
+
+static int ublk_get_max_ublks(char *buf, const struct kernel_param *kp)
+{
+ return sysfs_emit(buf, "%d\n", ublks_max);
+}
+
+static const struct kernel_param_ops ublk_max_ublks_ops = {
+ .set = ublk_set_max_ublks,
+ .get = ublk_get_max_ublks,
+};
+
+module_param_cb(ublks_max, &ublk_max_ublks_ops, NULL, 0644);
MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default: 64)");
MODULE_AUTHOR("Ming Lei <ming.lei@xxxxxxxxxx>");
--
2.34.1
