mirror of https://gitee.com/openkylin/linux.git
staging: comedi: comedi_bond: use bitmap to record opened/closed minors
`do_dev_config()` currently records the comedi minor devices it has opened by setting `devs_opened[minor]` to the pointer returned by `comedi_open()`. This is checked to avoid opening the same minor device twice. The pointer values in `devs_opened[]` aren't needed; we only need to record which minor device numbers are being used. Change `devs_opened` to a bitmap (declared with `DECLARE_BITMAP()`) of length `COMEDI_NUM_BOARD_MINORS` as the minor device numbers are range-checked to fit in a bitmap of this length. Use `test_and_set_bit()` to record the minor device numbers we attempt to open with `comedi_open()`. `bonding_detach()` calls `comedi_close()` to close the comedi minor devices. Since the minor device numbers may be repeated in its list of bonded subdevices, it currently uses a simple `unsigned long devs_closed` variable as a bitmap to keep track of which minor device numbers it has already closed to avoid closing them twice. As a single `unsigned long` consists of less than `COMEDI_NUM_BOARD_MINORS` bits on a 32-bit machine, change `devs_closed to a bitmap of this length using `DECLARE_BITMAP()` and use `test_and_set_bit()` to avoid calling `comedi_close()` more than once for each minor device number in use. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -190,10 +190,10 @@ static void *realloc(const void *oldmem, size_t newlen, size_t oldlen)
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static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
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{
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struct comedi_bond_private *devpriv = dev->private;
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DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS);
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int i;
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struct comedi_device *devs_opened[COMEDI_NUM_BOARD_MINORS];
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memset(devs_opened, 0, sizeof(devs_opened));
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memset(&devs_opened, 0, sizeof(devs_opened));
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devpriv->name[0] = 0;
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/*
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* Loop through all comedi devices specified on the command-line,
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@ -216,7 +216,7 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
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"Cannot bond this driver to itself!\n");
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return -EINVAL;
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}
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if (devs_opened[minor]) {
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if (test_and_set_bit(minor, devs_opened)) {
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dev_err(dev->class_dev,
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"Minor %d specified more than once!\n", minor);
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return -EINVAL;
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@ -225,7 +225,7 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it)
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snprintf(file, sizeof(file), "/dev/comedi%u", minor);
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file[sizeof(file) - 1] = 0;
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d = devs_opened[minor] = comedi_open(file);
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d = comedi_open(file);
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if (!d) {
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dev_err(dev->class_dev,
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@ -342,19 +342,19 @@ static int bonding_attach(struct comedi_device *dev,
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static void bonding_detach(struct comedi_device *dev)
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{
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struct comedi_bond_private *devpriv = dev->private;
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unsigned long devs_closed = 0;
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if (devpriv) {
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DECLARE_BITMAP(devs_closed, COMEDI_NUM_BOARD_MINORS);
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memset(&devs_closed, 0, sizeof(devs_closed));
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while (devpriv->ndevs-- && devpriv->devs) {
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struct bonded_device *bdev;
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bdev = devpriv->devs[devpriv->ndevs];
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if (!bdev)
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continue;
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if (!(devs_closed & (0x1 << bdev->minor))) {
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if (!test_and_set_bit(bdev->minor, devs_closed))
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comedi_close(bdev->dev);
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devs_closed |= (0x1 << bdev->minor);
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}
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kfree(bdev);
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}
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kfree(devpriv->devs);
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