Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [ 169/171] staging: comedi: dont hijack hardware device private data | Date | Tue, 15 Jan 2013 14:45:34 -0800 |
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3.4-stable review patch. If anyone has any objections, please let me know.
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From: Ian Abbott <abbotti@mev.co.uk>
commit c43435d7722134ed1fda58ce1025f41029bd58ad upstream.
comedi_auto_config() associates a Comedi minor device number with an auto-configured hardware device and comedi_auto_unconfig() disassociates it. Currently, these use the hardware device's private data pointer to point to some allocated storage holding the minor device number. This is a bit of a waste of the hardware device's private data pointer, preventing it from being used for something more useful by the low-level comedi device drivers. For example, it would make more sense if comedi_usb_auto_config() was passed a pointer to the struct usb_interface instead of the struct usb_device, but this cannot be done currently because the low-level comedi drivers already use the private data pointer in the struct usb_interface for something more useful.
This patch stops the comedi core hijacking the hardware device's private data pointer. Instead, comedi_auto_config() stores a pointer to the hardware device's struct device in the struct comedi_device_file_info associated with the minor device number, and comedi_auto_unconfig() calls new function comedi_find_board_minor() to recover the minor device number associated with the hardware device.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/staging/comedi/comedi_fops.c | 18 ++++++++++++++++++ drivers/staging/comedi/comedidev.h | 1 + drivers/staging/comedi/drivers.c | 34 ++++++++++------------------------ drivers/staging/comedi/internal.h | 1 + 4 files changed, 30 insertions(+), 24 deletions(-)
--- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2210,6 +2210,7 @@ int comedi_alloc_board_minor(struct devi kfree(info); return -ENOMEM; } + info->hardware_device = hardware_device; comedi_device_init(info->device); spin_lock_irqsave(&comedi_file_info_table_lock, flags); for (i = 0; i < COMEDI_NUM_BOARD_MINORS; ++i) { @@ -2298,6 +2299,23 @@ void comedi_free_board_minor(unsigned mi } } +int comedi_find_board_minor(struct device *hardware_device) +{ + int minor; + struct comedi_device_file_info *info; + + for (minor = 0; minor < COMEDI_NUM_BOARD_MINORS; minor++) { + spin_lock(&comedi_file_info_table_lock); + info = comedi_file_info_table[minor]; + if (info && info->hardware_device == hardware_device) { + spin_unlock(&comedi_file_info_table_lock); + return minor; + } + spin_unlock(&comedi_file_info_table_lock); + } + return -ENODEV; +} + int comedi_alloc_subdevice_minor(struct comedi_device *dev, struct comedi_subdevice *s) { --- a/drivers/staging/comedi/comedidev.h +++ b/drivers/staging/comedi/comedidev.h @@ -234,6 +234,7 @@ struct comedi_device_file_info { struct comedi_device *device; struct comedi_subdevice *read_subdevice; struct comedi_subdevice *write_subdevice; + struct device *hardware_device; }; #ifdef CONFIG_COMEDI_DEBUG --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -822,25 +822,14 @@ static int comedi_auto_config(struct dev int minor; struct comedi_device_file_info *dev_file_info; int retval; - unsigned *private_data = NULL; - if (!comedi_autoconfig) { - dev_set_drvdata(hardware_device, NULL); + if (!comedi_autoconfig) return 0; - } minor = comedi_alloc_board_minor(hardware_device); if (minor < 0) return minor; - private_data = kmalloc(sizeof(unsigned), GFP_KERNEL); - if (private_data == NULL) { - retval = -ENOMEM; - goto cleanup; - } - *private_data = minor; - dev_set_drvdata(hardware_device, private_data); - dev_file_info = comedi_get_device_file_info(minor); memset(&it, 0, sizeof(it)); @@ -853,25 +842,22 @@ static int comedi_auto_config(struct dev retval = comedi_device_attach(dev_file_info->device, &it); mutex_unlock(&dev_file_info->device->mutex); -cleanup: - if (retval < 0) { - kfree(private_data); + if (retval < 0) comedi_free_board_minor(minor); - } return retval; } static void comedi_auto_unconfig(struct device *hardware_device) { - unsigned *minor = (unsigned *)dev_get_drvdata(hardware_device); - if (minor == NULL) - return; - - BUG_ON(*minor >= COMEDI_NUM_BOARD_MINORS); + int minor; - comedi_free_board_minor(*minor); - dev_set_drvdata(hardware_device, NULL); - kfree(minor); + if (hardware_device == NULL) + return; + minor = comedi_find_board_minor(hardware_device); + if (minor < 0) + return; + BUG_ON(minor >= COMEDI_NUM_BOARD_MINORS); + comedi_free_board_minor(minor); } int comedi_pci_auto_config(struct pci_dev *pcidev, const char *board_name) --- a/drivers/staging/comedi/internal.h +++ b/drivers/staging/comedi/internal.h @@ -7,6 +7,7 @@ int insn_inval(struct comedi_device *dev struct comedi_insn *insn, unsigned int *data); int comedi_alloc_board_minor(struct device *hardware_device); void comedi_free_board_minor(unsigned minor); +int comedi_find_board_minor(struct device *hardware_device); void comedi_reset_async_buf(struct comedi_async *async); int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s, unsigned long new_size);
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