kernel/linux.git/include/linux/comedi, branch master

comedi: isadma: use kzalloc_flex

2026-04-02T13:52:49+00:00

Switched struct pointer member to a flexible array member to get rid of kzalloc_objs as there's no need for them to be separately allocated. AAdded __counted_by for extra runtime analysis. Signed-off-by: Rosen Penev Link: https://patch.msgid.link/20260311232459.18407-1-rosenp@gmail.com Signed-off-by: Greg Kroah-Hartman

comedi: add comedi_check_request_region()

2026-04-02T13:49:36+00:00

There is an existing comedi_request_region(dev, start, len) function used by COMEDI drivers for legacy devices to request an I/O port region starting at a specified base address (which must be non-zero) and with a specified length. It uses request_region(). On success, it sets dev->iobase and dev->iolen and returns 0. There is a alternative function __comedi_request_region(dev, start, len) which does the same thing without setting dev->iobase and dev->iolen. Most hardware devices have restrictions on the allowed I/O port base address and alignment, so add new functions comedi_check_request_region(dev, start, len, minstart, maxend, minalign) and __comedi_check_request_region(dev, start, len, minstart, maxend, minalign) to perform these additional checks. Turn the original functions into static inline wrapper functions that call the new functions. Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20260130170416.49994-2-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: comedi_8254: correct kernel-doc warnings

2026-01-16T15:33:17+00:00

Correct typos in 3 struct member descriptions to eliminate all kernel-doc warnings in comedi_8254.h: Warning: include/linux/comedi/comedi_8254.h:112 struct member 'next_div' not described in 'comedi_8254' Warning: include/linux/comedi/comedi_8254.h:112 struct member 'clock_src' not described in 'comedi_8254' Warning: include/linux/comedi/comedi_8254.h:112 struct member 'gate_src' not described in 'comedi_8254' Signed-off-by: Randy Dunlap Reviewed-by: Ian Abbott Link: https://patch.msgid.link/20251214202727.2215461-1-rdunlap@infradead.org Signed-off-by: Greg Kroah-Hartman

comedi: kcomedilib: Add loop checking variants of open and close

2025-11-26T13:20:10+00:00

Add `comedi_open_from(path, from)` and `comedi_close_from(dev, from)` as variants of the existing `comedi_from(path)` and `comedi_close(dev)`. The additional `from` parameter is a minor device number that tells the function that the COMEDI device is being opened or closed from another COMEDI device if the value is in the range [0, `COMEDI_NUM_BOARD_MINORS`-1]. In that case the function will refuse to open the device if it would lead to a chain of devices opening each other. (It will also impose a limit on the number of simultaneous opens from one device to another because we need to count those.) The new functions are intended to be used by the "comedi_bond" driver, which is the only driver that uses the existing `comedi_open()` and `comedi_close()` functions. The new functions will be used to avoid some possible deadlock situations. Replace the existing, exported `comedi_open()` and `comedi_close()` functions with inline wrapper functions that call the newly exported `comedi_open_from()` and `comedi_close_from()` functions. Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20251027153748.4569-2-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: Add reference counting for Comedi command handling

2025-11-26T13:19:41+00:00

For interrupts from badly behaved hardware (as emulated by Syzbot), it is possible for the Comedi core functions that manage the progress of asynchronous data acquisition to be called from driver ISRs while no asynchronous command has been set up, which can cause problems such as invalid pointer dereferencing or dividing by zero. To help protect against that, introduce new functions to maintain a reference counter for asynchronous commands that are being set up. `comedi_get_is_subdevice_running(s)` will check if a command has been set up on a subdevice and is still marked as running, and if so will increment the reference counter and return `true`, otherwise it will return `false` without modifying the reference counter. `comedi_put_is_subdevice_running(s)` will decrement the reference counter and set a completion event when decremented to 0. Change the `do_cmd_ioctl()` function (responsible for setting up the asynchronous command) to reinitialize the completion event and set the reference counter to 1 before it marks the subdevice as running. Change the `do_become_nonbusy()` function (responsible for destroying a completed command) to call `comedi_put_is_subdevice_running(s)` and wait for the completion event after marking the subdevice as not running. Because the subdevice normally gets marked as not running before the call to `do_become_nonbusy()` (and may also be called when the Comedi device is being detached from the low-level driver), add a new flag `COMEDI_SRF_BUSY` to the set of subdevice run-flags that indicates that an asynchronous command was set up and will need to be destroyed. This flag is set by `do_cmd_ioctl()` and cleared and checked by `do_become_nonbusy()`. Subsequent patches will change the Comedi core functions that are called from low-level drivers for asynchrous command handling to make use of the `comedi_get_is_subdevice_running()` and `comedi_put_is_subdevice_running()` functions, and will modify the ISRs of some of these low-level drivers if they dereference the subdevice's `async` pointer directly. Signed-off-by: Ian Abbott Link: https://patch.msgid.link/20251023133001.8439-2-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: remove the mapping of the Comedi buffer in vmalloc address space

2025-04-25T13:53:19+00:00

Now that all the code that accesses the Comedi buffer data does so page-by-page, using the `virt_addr` member of `struct comedi_buf_page` to point to the data of each page, do not linearly map the buffer into vmalloc address space (pointed to by the `prealloc_buf` member of `struct comedi_async`). That was only done for convenience, but was not done for those drivers that need a DMA coherent buffer, which is allocated in a single chunk. Remove the `prealloc_buf` member as it is no longer used. Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20250415114008.5977-4-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: Annotate struct comedi_lrange with __counted_by

2023-10-05T11:34:05+00:00

Prepare for the coming implementation by GCC and Clang of the __counted_by attribute. Flexible array members annotated with __counted_by can have their accesses bounds-checked at run-time checking via CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family functions). Signed-off-by: Christophe JAILLET Reviewed-by: Kees Cook Reviewed-by: "Gustavo A. R. Silva" Link: https://lore.kernel.org/r/5c3b7459b820e22e2ac6ce892d4aadcc119cc919.1696065263.git.christophe.jaillet@wanadoo.fr Signed-off-by: Greg Kroah-Hartman

comedi: comedi_8255: Conditionally remove I/O port support

2023-10-05T11:34:04+00:00

In a future patch, the port I/O functions (`inb()`, `outb()`, and friends will only be declared in the `HAS_IOPORT` configuration option is enabled. The comedi_8255 module supports both port I/O and memory-mapped I/O. Conditionally compile the parts of the module that use port I/O if and only if the `CONFIG_HAS_IOPORT` macro is defined so that it can still be built if the port I/O functions have not been declared. If the `CONFIG_HAS_IOPORT` macro is undefined, replace the GPL-exported `subdev_8255_io_init()` function with a dummy static inline version that just returns `-ENXIO`. Cc: Arnd Bergmann Cc: Niklas Schnelle Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20230913170712.111719-8-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: comedi_8255: Rework subdevice initialization functions

2023-10-05T11:34:04+00:00

Comedi drivers can initialize an 8255 subdevice in I/O space by calling `subdev_8255_init()`, or in memory-mapped I/O space by calling `subdev_8255_mm_init()`, or by supplying a call-back function pointer and context to either of those functions. Change it so that a new function `subdev_8255_cb_init()` shall be called instead when supplying a callback function and context, and remove the call-back function parameter from `subdev_8255_init()` and `subdev_8255_mm_init()`. Also rename `subdev_8255_init()` to `subdev_8255_io_init()`. The parameters are changing, so might as well rename it at the same time. Also rename the `regbase` member of `struct subdev_8255_private` to `context` since this holds the context for the call-back function call. Cc: Arnd Bergmann Cc: Niklas Schnelle Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20230913170712.111719-7-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman

comedi: comedi_8254: Conditionally remove I/O port support

2023-10-05T11:34:04+00:00

The comedi_8254 module supports both port I/O and memory-mapped I/O. In a future patch, the port I/O functions (`inb()`, `outb()`, and friends) will only be declared if the `HAS_IOPORT` configuration option is enabled. Conditionally compile the parts of the module that use port I/O so they are compiled if and only if the `CONFIG_HAS_IOPORT` macro is defined, so that it can still be built if the port I/O functions have not been declared. If `CONFIG_HAS_IOPORT` is undefined, replace the GPL-exported `comedi_8254_io_alloc()` function with a dummy static inline version that just returns `ERR_PTR(-ENXIO)`. Cc: Arnd Bergmann Cc: Niklas Schnelle Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20230913170712.111719-5-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman