From f59ebeda209306f10e33016b510996f54cc5248e Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 23 Aug 2013 14:45:02 +0100 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers/comedi_bond.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/staging/comedi/drivers/comedi_bond.c b/drivers/staging/comedi/drivers/comedi_bond.c index dd93e4f..c0a427c 100644 --- a/drivers/staging/comedi/drivers/comedi_bond.c +++ b/drivers/staging/comedi/drivers/comedi_bond.c @@ -190,10 +190,10 @@ static void *realloc(const void *oldmem, size_t newlen, size_t oldlen) static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it) { struct comedi_bond_private *devpriv = dev->private; + DECLARE_BITMAP(devs_opened, COMEDI_NUM_BOARD_MINORS); int i; - struct comedi_device *devs_opened[COMEDI_NUM_BOARD_MINORS]; - memset(devs_opened, 0, sizeof(devs_opened)); + memset(&devs_opened, 0, sizeof(devs_opened)); devpriv->name[0] = 0; /* * Loop through all comedi devices specified on the command-line, @@ -216,7 +216,7 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it) "Cannot bond this driver to itself!\n"); return -EINVAL; } - if (devs_opened[minor]) { + if (test_and_set_bit(minor, devs_opened)) { dev_err(dev->class_dev, "Minor %d specified more than once!\n", minor); return -EINVAL; @@ -225,7 +225,7 @@ static int do_dev_config(struct comedi_device *dev, struct comedi_devconfig *it) snprintf(file, sizeof(file), "/dev/comedi%u", minor); file[sizeof(file) - 1] = 0; - d = devs_opened[minor] = comedi_open(file); + d = comedi_open(file); if (!d) { dev_err(dev->class_dev, @@ -342,19 +342,19 @@ static int bonding_attach(struct comedi_device *dev, static void bonding_detach(struct comedi_device *dev) { struct comedi_bond_private *devpriv = dev->private; - unsigned long devs_closed = 0; if (devpriv) { + DECLARE_BITMAP(devs_closed, COMEDI_NUM_BOARD_MINORS); + + memset(&devs_closed, 0, sizeof(devs_closed)); while (devpriv->ndevs-- && devpriv->devs) { struct bonded_device *bdev; bdev = devpriv->devs[devpriv->ndevs]; if (!bdev) continue; - if (!(devs_closed & (0x1 << bdev->minor))) { + if (!test_and_set_bit(bdev->minor, devs_closed)) comedi_close(bdev->dev); - devs_closed |= (0x1 << bdev->minor); - } kfree(bdev); } kfree(devpriv->devs); -- 2.7.4