From 8698d3feccda66fcb52748e7c7690bd1003f7849 Mon Sep 17 00:00:00 2001 From: Alexander Chiang Date: Tue, 2 Feb 2010 19:08:45 +0000 Subject: [PATCH] IB/umad: Increase maximum devices supported Some large systems may support more than IB_UMAD_MAX_PORTS (currently 64). This change allows us to support more ports in a backwards-compatible manner. The first IB_UMAD_MAX_PORTS keep the same major/minor device numbers they've always had. If there are more than IB_UMAD_MAX_PORTS, we then dynamically request a new major device number (new minors start at 0). Signed-off-by: Alex Chiang Signed-off-by: Roland Dreier --- drivers/infiniband/core/user_mad.c | 50 +++++++++++++++++++++++++++++++++----- 1 file changed, 44 insertions(+), 6 deletions(-) diff --git a/drivers/infiniband/core/user_mad.c b/drivers/infiniband/core/user_mad.c index 5a66bd0..57818ae 100644 --- a/drivers/infiniband/core/user_mad.c +++ b/drivers/infiniband/core/user_mad.c @@ -971,6 +971,28 @@ static ssize_t show_abi_version(struct class *class, char *buf) } static CLASS_ATTR(abi_version, S_IRUGO, show_abi_version, NULL); +static dev_t overflow_maj; +static DECLARE_BITMAP(overflow_map, IB_UMAD_MAX_PORTS); +static int find_overflow_devnum(void) +{ + int ret; + + if (!overflow_maj) { + ret = alloc_chrdev_region(&overflow_maj, 0, IB_UMAD_MAX_PORTS * 2, + "infiniband_mad"); + if (ret) { + printk(KERN_ERR "user_mad: 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_port *port) { @@ -981,11 +1003,19 @@ static int ib_umad_init_port(struct ib_device *device, int port_num, devnum = find_first_zero_bit(dev_map, IB_UMAD_MAX_PORTS); if (devnum >= IB_UMAD_MAX_PORTS) { spin_unlock(&port_lock); - return -1; + devnum = find_overflow_devnum(); + if (devnum < 0) + return -1; + + spin_lock(&port_lock); + port->dev_num = devnum + IB_UMAD_MAX_PORTS; + base = devnum + overflow_maj; + set_bit(devnum, overflow_map); + } else { + port->dev_num = devnum; + base = devnum + base_dev; + set_bit(devnum, dev_map); } - port->dev_num = devnum; - base = devnum + base_dev; - set_bit(devnum, dev_map); spin_unlock(&port_lock); port->ib_dev = device; @@ -1042,7 +1072,10 @@ err_dev: err_cdev: cdev_del(&port->cdev); - clear_bit(devnum, dev_map); + if (port->dev_num < IB_UMAD_MAX_PORTS) + clear_bit(devnum, dev_map); + else + clear_bit(devnum, overflow_map); return -1; } @@ -1079,7 +1112,10 @@ static void ib_umad_kill_port(struct ib_umad_port *port) mutex_unlock(&port->file_mutex); - clear_bit(port->dev_num, dev_map); + 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); } static void ib_umad_add_one(struct ib_device *device) @@ -1187,6 +1223,8 @@ 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); } module_init(ib_umad_init); -- 2.7.4