From ccfabf967ddeff4dad95fe1b97ab3bc2f2da3683 Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Fri, 30 Mar 2012 17:14:58 +0100 Subject: [PATCH] staging: comedi: don't hijack hardware device private data 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 Signed-off-by: Greg Kroah-Hartman Signed-off-by: Ben Hutchings --- 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(-) diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index 9465bcea9260..ab9f5ed344da 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2207,6 +2207,7 @@ int comedi_alloc_board_minor(struct device *hardware_device) 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) { @@ -2295,6 +2296,23 @@ void comedi_free_board_minor(unsigned minor) } } +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) { diff --git a/drivers/staging/comedi/comedidev.h b/drivers/staging/comedi/comedidev.h index 7a0d4bcbc355..00d3c65589bd 100644 --- 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 diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index db1fd63aaab3..538b5680a4f0 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -823,25 +823,14 @@ static int comedi_auto_config(struct device *hardware_device, 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)); @@ -854,25 +843,22 @@ static int comedi_auto_config(struct device *hardware_device, 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) diff --git a/drivers/staging/comedi/internal.h b/drivers/staging/comedi/internal.h index 434ce3433368..4208fb4cf0ff 100644 --- 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_subdevice *s, 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); -- 2.39.2