nvme-pci: use unsigned for io queue depth

The NVMe PCIe declares module parameter io_queue_depth as int. Change
this to u16 as queue depth can never be negative. Now to reflect this
update module parameter getter function from param_get_int() ->
param_get_uint() and respective setter function with type of n changed
from int to u16 with param_set_int() to param_set_ushort(). Finally
update struct nvme_dev q_depth member to u16 and use u16 in min_t()
when calculating dev->q_depth in the nvme_pci_enable() (since q_depth is
now u16) and use unsigned int instead of int when calculating
dev->tagset.queue_depth as target variable tagset->queue_depth is of type
unsigned int in nvme_dev_add().

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

Author: ChaitanayaKulkarni

drivers/nvme/host/pci.c

@@ -61,10 +61,10 @@ MODULE_PARM_DESC(sgl_threshold,
 static int io_queue_depth_set(const char *val, const struct kernel_param *kp);
 static const struct kernel_param_ops io_queue_depth_ops = {
 	.set = io_queue_depth_set,
-	.get = param_get_int,
+	.get = param_get_uint,
 };
 
-static int io_queue_depth = 1024;
+static unsigned int io_queue_depth = 1024;
 module_param_cb(io_queue_depth, &io_queue_depth_ops, &io_queue_depth, 0644);
 MODULE_PARM_DESC(io_queue_depth, "set io queue depth, should >= 2");
 
@@ -115,7 +115,7 @@ struct nvme_dev {
 	unsigned max_qid;
 	unsigned io_queues[HCTX_MAX_TYPES];
 	unsigned int num_vecs;
-	int q_depth;
+	u16 q_depth;
 	int io_sqes;
 	u32 db_stride;
 	void __iomem *bar;
@@ -151,13 +151,14 @@ struct nvme_dev {
 
 static int io_queue_depth_set(const char *val, const struct kernel_param *kp)
 {
-	int n = 0, ret;
+	int ret;
+	u16 n;
 
-	ret = kstrtoint(val, 10, &n);
+	ret = kstrtou16(val, 10, &n);
 	if (ret != 0 || n < 2)
 		return -EINVAL;
 
-	return param_set_int(val, kp);
+	return param_set_ushort(val, kp);
 }
 
 static inline unsigned int sq_idx(unsigned int qid, u32 stride)
@@ -2261,8 +2262,8 @@ static void nvme_dev_add(struct nvme_dev *dev)
 			dev->tagset.nr_maps++;
 		dev->tagset.timeout = NVME_IO_TIMEOUT;
 		dev->tagset.numa_node = dev->ctrl.numa_node;
-		dev->tagset.queue_depth =
-				min_t(int, dev->q_depth, BLK_MQ_MAX_DEPTH) - 1;
+		dev->tagset.queue_depth = min_t(unsigned int, dev->q_depth,
+						BLK_MQ_MAX_DEPTH) - 1;
 		dev->tagset.cmd_size = sizeof(struct nvme_iod);
 		dev->tagset.flags = BLK_MQ_F_SHOULD_MERGE;
 		dev->tagset.driver_data = dev;
@@ -2321,7 +2322,7 @@ static int nvme_pci_enable(struct nvme_dev *dev)
 
 	dev->ctrl.cap = lo_hi_readq(dev->bar + NVME_REG_CAP);
 
-	dev->q_depth = min_t(int, NVME_CAP_MQES(dev->ctrl.cap) + 1,
+	dev->q_depth = min_t(u16, NVME_CAP_MQES(dev->ctrl.cap) + 1,
 				io_queue_depth);
 	dev->ctrl.sqsize = dev->q_depth - 1; /* 0's based queue depth */
 	dev->db_stride = 1 << NVME_CAP_STRIDE(dev->ctrl.cap);