[PATCH 1/6] null_blk: check for valid submit_queue value

[Chaitanya Kulkarni <kch@xxxxxxxxxx>]

Right now we don't check for valid module parameter value for
submit_queue, that allows user to set negative values.

Move null_param_store_val() at the top so we can reuse that code in
module param ops.

Add a callback null_set_submit_queues() to error out when submit_queue
value is < 1 before module is loaded.

Signed-off-by: Chaitanya Kulkarni <kch@xxxxxxxxxx>
---
 drivers/block/null_blk/main.c | 42 +++++++++++++++++++++--------------
 1 file changed, 25 insertions(+), 17 deletions(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index 1f154f92f4c2..c8dbff120c65 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -77,6 +77,21 @@ enum {
 	NULL_IRQ_TIMER		= 2,
 };
 
+static int null_param_store_val(const char *str, int *val, int min, int max)
+{
+	int ret, new_val;
+
+	ret = kstrtoint(str, 10, &new_val);
+	if (ret)
+		return -EINVAL;
+
+	if (new_val < min || new_val > max)
+		return -EINVAL;
+
+	*val = new_val;
+	return 0;
+}
+
 static bool g_virt_boundary = false;
 module_param_named(virt_boundary, g_virt_boundary, bool, 0444);
 MODULE_PARM_DESC(virt_boundary, "Require a virtual boundary for the device. Default: False");
@@ -86,7 +101,16 @@ module_param_named(no_sched, g_no_sched, int, 0444);
 MODULE_PARM_DESC(no_sched, "No io scheduler");
 
 static int g_submit_queues = 1;
-module_param_named(submit_queues, g_submit_queues, int, 0444);
+static int null_set_submit_queues(const char *s, const struct kernel_param *p)
+{
+	return null_param_store_val(s, &g_submit_queues, 1, INT_MAX);
+}
+
+static const struct kernel_param_ops null_submit_queues_param_ops = {
+	.set	= null_set_submit_queues,
+	.get	= param_get_int,
+};
+device_param_cb(submit_queues, &null_submit_queues_param_ops, &g_submit_queues, 0444);
 MODULE_PARM_DESC(submit_queues, "Number of submission queues");
 
 static int g_poll_queues = 1;
@@ -116,22 +140,6 @@ MODULE_PARM_DESC(init_hctx, "Fault injection to fail hctx init. init_hctx=<inter
 #endif
 
 static int g_queue_mode = NULL_Q_MQ;
-
-static int null_param_store_val(const char *str, int *val, int min, int max)
-{
-	int ret, new_val;
-
-	ret = kstrtoint(str, 10, &new_val);
-	if (ret)
-		return -EINVAL;
-
-	if (new_val < min || new_val > max)
-		return -EINVAL;
-
-	*val = new_val;
-	return 0;
-}
-
 static int null_set_queue_mode(const char *str, const struct kernel_param *kp)
 {
 	return null_param_store_val(str, &g_queue_mode, NULL_Q_BIO, NULL_Q_MQ);
-- 
2.29.0