[PATCH V2 2/9] null_blk: check for valid submit_queue value

From: Chaitanya Kulkarni <kch@nvidia.com>
To: <linux-block@vger.kernel.org>
Cc: <axboe@kernel.dk>, <kch@nvidia.com>,
	<damien.lemoal@opensource.wdc.com>, <johannes.thumshirn@wdc.com>,
	<ming.lei@redhat.com>, <bvanassche@acm.org>,
	<shinichiro.kawasaki@wdc.com>, <vincent.fu@samsung.com>
Subject: [PATCH V2 2/9] null_blk: check for valid submit_queue value
Date: Thu, 30 Mar 2023 14:31:27 -0700	[thread overview]
Message-ID: <20230330213134.131298-3-kch@nvidia.com> (raw)
In-Reply-To: <20230330213134.131298-1-kch@nvidia.com>

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

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@nvidia.com>
---
 drivers/block/null_blk/main.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/block/null_blk/main.c b/drivers/block/null_blk/main.c
index cf6937f4cfa1..9e3df92d0b98 100644
--- a/drivers/block/null_blk/main.c
+++ b/drivers/block/null_blk/main.c
@@ -100,8 +100,18 @@ static int g_no_sched;
 module_param_named(no_sched, g_no_sched, int, 0444);
 MODULE_PARM_DESC(no_sched, "No io scheduler");
 
+static int null_set_submit_queues(const char *s, const struct kernel_param *kp)
+{
+	return null_param_store_int(s, kp->arg, 1, INT_MAX);
+}
+
+static const struct kernel_param_ops null_submit_queues_param_ops = {
+	.set	= null_set_submit_queues,
+	.get	= param_get_int,
+};
+
 static int g_submit_queues = 1;
-module_param_named(submit_queues, g_submit_queues, int, 0444);
+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;
-- 
2.29.0

