IB/core: Increase number of char device minors

There is a need to increase number of possible char devices to support
large number of SR-IOV instances. The current limit is in the range of
64-128 devices/ports. Increase it to support up to 1024.

The patch performs the following steps to refactor the code:
1. Removes the split bitmap for fixed and overflow dev numbers.
2. Pre-allocates the non-legacy major number range during driver
   initialization, choosen for simplicity.
3. Add new define (RDMA_MAX_PORTS) that is shared between all drivers.
   This is the maximum total number of ports on all struct ib_devices.
4. Set RDMA_MAX_PORTS to 1024.

Signed-off-by: Huy Nguyen <huyn@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

1 files changed, 48 insertions, 55 deletions

diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c
index 608176e9cd5d..f0ed883492ec 100644
--- a/drivers/infiniband/core/user_mad.c
+++ b/drivers/infiniband/core/user_mad.c
@@ -55,16 +55,21 @@
 #include <rdma/ib_mad.h>
 #include <rdma/ib_user_mad.h>
 
+#include "core_priv.h"
+
 MODULE_AUTHOR("Roland Dreier");
 MODULE_DESCRIPTION("InfiniBand userspace MAD packet access");
 MODULE_LICENSE("Dual BSD/GPL");
 
 enum {
-	IB_UMAD_MAX_PORTS  = 64,
+	IB_UMAD_MAX_PORTS  = RDMA_MAX_PORTS,
 	IB_UMAD_MAX_AGENTS = 32,
 
 	IB_UMAD_MAJOR      = 231,
-	IB_UMAD_MINOR_BASE = 0
+	IB_UMAD_MINOR_BASE = 0,
+	IB_UMAD_NUM_FIXED_MINOR = 64,
+	IB_UMAD_NUM_DYNAMIC_MINOR = IB_UMAD_MAX_PORTS - IB_UMAD_NUM_FIXED_MINOR,
+	IB_ISSM_MINOR_BASE        = IB_UMAD_NUM_FIXED_MINOR,
 };
 
 /*
@@ -127,7 +132,11 @@ struct ib_umad_packet {
 
 static struct class *umad_class;
 
-static const dev_t base_dev = MKDEV(IB_UMAD_MAJOR, IB_UMAD_MINOR_BASE);
+static const dev_t base_umad_dev = MKDEV(IB_UMAD_MAJOR, IB_UMAD_MINOR_BASE);
+static const dev_t base_issm_dev = MKDEV(IB_UMAD_MAJOR, IB_UMAD_MINOR_BASE) +
+				   IB_UMAD_NUM_FIXED_MINOR;
+static dev_t dynamic_umad_dev;
+static dev_t dynamic_issm_dev;
 
 static DECLARE_BITMAP(dev_map, IB_UMAD_MAX_PORTS);
 
@@ -1141,49 +1150,25 @@ static DEVICE_ATTR(port, S_IRUGO, show_port, NULL);
 static CLASS_ATTR_STRING(abi_version, S_IRUGO,
 			 __stringify(IB_USER_MAD_ABI_VERSION));
 
-static dev_t overflow_maj;
-static DECLARE_BITMAP(overflow_map, IB_UMAD_MAX_PORTS);
-static int find_overflow_devnum(struct ib_device *device)
-{
-	int ret;
-
-	if (!overflow_maj) {
-		ret = alloc_chrdev_region(&overflow_maj, 0, IB_UMAD_MAX_PORTS * 2,
-					  "infiniband_mad");
-		if (ret) {
-			dev_err(&device->dev,
-				"couldn't register dynamic device number\n");
-			return ret;
-		}
-	}
-
-	ret = find_first_zero_bit(overflow_map, IB_UMAD_MAX_PORTS);
-	if (ret >= IB_UMAD_MAX_PORTS)
-		return -1;
-
-	return ret;
-}
-
 static int ib_umad_init_port(struct ib_device *device, int port_num,
 			     struct ib_umad_device *umad_dev,
 			     struct ib_umad_port *port)
 {
 	int devnum;
-	dev_t base;
+	dev_t base_umad;
+	dev_t base_issm;
 
 	devnum = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS);
-	if (devnum >= IB_UMAD_MAX_PORTS) {
-		devnum = find_overflow_devnum(device);
-		if (devnum < 0)
-			return -1;
-
-		port->dev_num = devnum + IB_UMAD_MAX_PORTS;
-		base = devnum + overflow_maj;
-		set_bit(devnum, overflow_map);
+	if (devnum >= IB_UMAD_MAX_PORTS)
+		return -1;
+	port->dev_num = devnum;
+	set_bit(devnum, dev_map);
+	if (devnum >= IB_UMAD_NUM_FIXED_MINOR) {
+		base_umad = dynamic_umad_dev + devnum - IB_UMAD_NUM_FIXED_MINOR;
+		base_issm = dynamic_issm_dev + devnum - IB_UMAD_NUM_FIXED_MINOR;
 	} else {
-		port->dev_num = devnum;
-		base = devnum + base_dev;
-		set_bit(devnum, dev_map);
+		base_umad = devnum + base_umad_dev;
+		base_issm = devnum + base_issm_dev;
 	}
 
 	port->ib_dev   = device;
@@ -1196,7 +1181,7 @@ static int ib_umad_init_port(struct ib_device *device, int port_num,
 	port->cdev.owner = THIS_MODULE;
 	cdev_set_parent(&port->cdev, &umad_dev->kobj);
 	kobject_set_name(&port->cdev.kobj, "umad%d", port->dev_num);
-	if (cdev_add(&port->cdev, base, 1))
+	if (cdev_add(&port->cdev, base_umad, 1))
 		goto err_cdev;
 
 	port->dev = device_create(umad_class, device->dev.parent,
@@ -1210,12 +1195,11 @@ static int ib_umad_init_port(struct ib_device *device, int port_num,
 	if (device_create_file(port->dev, &dev_attr_port))
 		goto err_dev;
 
-	base += IB_UMAD_MAX_PORTS;
 	cdev_init(&port->sm_cdev, &umad_sm_fops);
 	port->sm_cdev.owner = THIS_MODULE;
 	cdev_set_parent(&port->sm_cdev, &umad_dev->kobj);
 	kobject_set_name(&port->sm_cdev.kobj, "issm%d", port->dev_num);
-	if (cdev_add(&port->sm_cdev, base, 1))
+	if (cdev_add(&port->sm_cdev, base_issm, 1))
 		goto err_sm_cdev;
 
 	port->sm_dev = device_create(umad_class, device->dev.parent,
@@ -1242,10 +1226,7 @@ err_dev:
 
 err_cdev:
 	cdev_del(&port->cdev);
-	if (port->dev_num < IB_UMAD_MAX_PORTS)
-		clear_bit(devnum, dev_map);
-	else
-		clear_bit(devnum, overflow_map);
+	clear_bit(devnum, dev_map);
 
 	return -1;
 }
@@ -1279,11 +1260,7 @@ static void ib_umad_kill_port(struct ib_umad_port *port)
 	}
 
 	mutex_unlock(&port->file_mutex);
-
-	if (port->dev_num < IB_UMAD_MAX_PORTS)
-		clear_bit(port->dev_num, dev_map);
-	else
-		clear_bit(port->dev_num - IB_UMAD_MAX_PORTS, overflow_map);
+	clear_bit(port->dev_num, dev_map);
 }
 
 static void ib_umad_add_one(struct ib_device *device)
@@ -1359,13 +1336,23 @@ static int __init ib_umad_init(void)
 {
 	int ret;
 
-	ret = register_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2,
+	ret = register_chrdev_region(base_umad_dev,
+				     IB_UMAD_NUM_FIXED_MINOR * 2,
 				     "infiniband_mad");
 	if (ret) {
 		pr_err("couldn't register device number\n");
 		goto out;
 	}
 
+	ret = alloc_chrdev_region(&dynamic_umad_dev, 0,
+				  IB_UMAD_NUM_DYNAMIC_MINOR * 2,
+				  "infiniband_mad");
+	if (ret) {
+		pr_err("couldn't register dynamic device number\n");
+		goto out_alloc;
+	}
+	dynamic_issm_dev = dynamic_umad_dev + IB_UMAD_NUM_DYNAMIC_MINOR;
+
 	umad_class = class_create(THIS_MODULE, "infiniband_mad");
 	if (IS_ERR(umad_class)) {
 		ret = PTR_ERR(umad_class);
@@ -1393,7 +1380,12 @@ out_class:
 	class_destroy(umad_class);
 
 out_chrdev:
-	unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2);
+	unregister_chrdev_region(dynamic_umad_dev,
+				 IB_UMAD_NUM_DYNAMIC_MINOR * 2);
+
+out_alloc:
+	unregister_chrdev_region(base_umad_dev,
+				 IB_UMAD_NUM_FIXED_MINOR * 2);
 
 out:
 	return ret;
@@ -1403,9 +1395,10 @@ static void __exit ib_umad_cleanup(void)
 {
 	ib_unregister_client(&umad_client);
 	class_destroy(umad_class);
-	unregister_chrdev_region(base_dev, IB_UMAD_MAX_PORTS * 2);
-	if (overflow_maj)
-		unregister_chrdev_region(overflow_maj, IB_UMAD_MAX_PORTS * 2);
+	unregister_chrdev_region(base_umad_dev,
+				 IB_UMAD_NUM_FIXED_MINOR * 2);
+	unregister_chrdev_region(dynamic_umad_dev,
+				 IB_UMAD_NUM_DYNAMIC_MINOR * 2);
 }
 
 module_init(ib_umad_init);