IB/uverbs: Increase maximum devices supported
Some large systems may support more than IB_UVERBS_MAX_DEVICES (currently 32). This change allows us to support more devices in a backwards-compatible manner. The first IB_UVERBS_MAX_DEVICES keep the same major/minor device numbers that they've always had. If there are more than IB_UVERBS_MAX_DEVICES, we then dynamically request a new major device number (new minors start at 0). This change increases the maximum number of HCAs to 64 (from 32). Signed-off-by: Alex Chiang <achiang@hp.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
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parent
ddbd688301
commit
6d6a0e71ee
1 changed files with 50 additions and 6 deletions
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@ -728,6 +728,34 @@ static ssize_t show_abi_version(struct class *class, char *buf)
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}
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static CLASS_ATTR(abi_version, S_IRUGO, show_abi_version, NULL);
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static dev_t overflow_maj;
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static DECLARE_BITMAP(overflow_map, IB_UVERBS_MAX_DEVICES);
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/*
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* If we have more than IB_UVERBS_MAX_DEVICES, dynamically overflow by
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* requesting a new major number and doubling the number of max devices we
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* support. It's stupid, but simple.
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*/
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static int find_overflow_devnum(void)
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{
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int ret;
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if (!overflow_maj) {
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ret = alloc_chrdev_region(&overflow_maj, 0, IB_UVERBS_MAX_DEVICES,
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"infiniband_verbs");
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if (ret) {
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printk(KERN_ERR "user_verbs: couldn't register dynamic device number\n");
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return ret;
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}
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}
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ret = find_first_zero_bit(overflow_map, IB_UVERBS_MAX_DEVICES);
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if (ret >= IB_UVERBS_MAX_DEVICES)
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return -1;
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return ret;
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}
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static void ib_uverbs_add_one(struct ib_device *device)
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{
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int devnum;
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@ -748,11 +776,19 @@ static void ib_uverbs_add_one(struct ib_device *device)
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devnum = find_first_zero_bit(dev_map, IB_UVERBS_MAX_DEVICES);
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if (devnum >= IB_UVERBS_MAX_DEVICES) {
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spin_unlock(&map_lock);
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devnum = find_overflow_devnum();
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if (devnum < 0)
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goto err;
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}
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spin_lock(&map_lock);
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uverbs_dev->devnum = devnum + IB_UVERBS_MAX_DEVICES;
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base = devnum + overflow_maj;
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set_bit(devnum, overflow_map);
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} else {
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uverbs_dev->devnum = devnum;
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base = devnum + IB_UVERBS_BASE_DEV;
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set_bit(devnum, dev_map);
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}
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spin_unlock(&map_lock);
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uverbs_dev->ib_dev = device;
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@ -785,7 +821,10 @@ err_class:
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err_cdev:
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cdev_del(&uverbs_dev->cdev);
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if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
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clear_bit(devnum, dev_map);
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else
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clear_bit(devnum, overflow_map);
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err:
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kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
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@ -805,7 +844,10 @@ static void ib_uverbs_remove_one(struct ib_device *device)
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device_destroy(uverbs_class, uverbs_dev->cdev.dev);
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cdev_del(&uverbs_dev->cdev);
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if (uverbs_dev->devnum < IB_UVERBS_MAX_DEVICES)
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clear_bit(uverbs_dev->devnum, dev_map);
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else
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clear_bit(uverbs_dev->devnum - IB_UVERBS_MAX_DEVICES, overflow_map);
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kref_put(&uverbs_dev->ref, ib_uverbs_release_dev);
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wait_for_completion(&uverbs_dev->comp);
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@ -895,6 +937,8 @@ static void __exit ib_uverbs_cleanup(void)
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unregister_filesystem(&uverbs_event_fs);
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class_destroy(uverbs_class);
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unregister_chrdev_region(IB_UVERBS_BASE_DEV, IB_UVERBS_MAX_DEVICES);
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if (overflow_maj)
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unregister_chrdev_region(overflow_maj, IB_UVERBS_MAX_DEVICES);
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idr_destroy(&ib_uverbs_pd_idr);
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idr_destroy(&ib_uverbs_mr_idr);
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idr_destroy(&ib_uverbs_mw_idr);
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