c383e2d6da
Low-level comedi drivers registered with the comedi core by `comedi_driver_register()` are linked together into a simple linked list headed by the `comedi_drivers` variable and chained by the `next` member of `struct comedi_driver`. A driver is removed from the list by `comedi_driver_unregister()`. The driver list is iterated through by `comedi_device_attach()` when the `COMEDI_DEVCONFIG` ioctl is used to attach a "legacy" device to a driver, and is also iterated through by `comedi_read()` in "proc.c" when reading "/proc/comedi". There is currently no protection against items being added or removed from the list while it is being iterated. Add a mutex `comedi_drivers_list_lock` to be locked while adding or removing an item on the list, or when iterating through the list. `comedi_driver_unregister()` also checks for and detaches any devices using the driver. This is currently done before unlinking the driver from the list, but it makes more sense to unlink the driver from the list first to prevent `comedi_device_attach()` attempting to use it, so move the unlinking part to the start of the function. Also, in `comedi_device_attach()` hold on to the mutex until we've finished attempting to attach the device to avoid it interfering with the detachment in `comedi_driver_unregister()`. Signed-off-by: Ian Abbott <abbotti@mev.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
51 lines
1.4 KiB
C
51 lines
1.4 KiB
C
#ifndef _COMEDI_INTERNAL_H
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#define _COMEDI_INTERNAL_H
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#include <linux/types.h>
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/*
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* various internal comedi stuff
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*/
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int do_rangeinfo_ioctl(struct comedi_device *dev,
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struct comedi_rangeinfo __user *arg);
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struct comedi_device *comedi_alloc_board_minor(struct device *hardware_device);
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void comedi_release_hardware_device(struct device *hardware_device);
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int comedi_alloc_subdevice_minor(struct comedi_subdevice *s);
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void comedi_free_subdevice_minor(struct comedi_subdevice *s);
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int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
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unsigned long new_size);
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void comedi_buf_reset(struct comedi_async *async);
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unsigned int comedi_buf_write_n_allocated(struct comedi_async *async);
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extern unsigned int comedi_default_buf_size_kb;
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extern unsigned int comedi_default_buf_maxsize_kb;
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/* drivers.c */
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extern struct comedi_driver *comedi_drivers;
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extern struct mutex comedi_drivers_list_lock;
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int insn_inval(struct comedi_device *, struct comedi_subdevice *,
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struct comedi_insn *, unsigned int *);
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void comedi_device_detach(struct comedi_device *);
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int comedi_device_attach(struct comedi_device *, struct comedi_devconfig *);
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#ifdef CONFIG_PROC_FS
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/* proc.c */
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void comedi_proc_init(void);
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void comedi_proc_cleanup(void);
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#else
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static inline void comedi_proc_init(void)
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{
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}
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static inline void comedi_proc_cleanup(void)
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{
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}
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#endif
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#endif /* _COMEDI_INTERNAL_H */
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