kernel/linux.git/include/linux/comedi/comedidev.h, branch v6.19.11

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: Move the main COMEDI headers

2021-11-26T15:48:59+00:00

Move the main COMEDI driver headers out of "drivers/comedi/" into new directory "include/linux/comedi/". These are "comedidev.h", "comedilib.h", "comedi_pci.h", "comedi_pcmcia.h", and "comedi_usb.h". Additionally, move the user-space API header "comedi.h" into "include/uapi/linux/" and add "WITH Linux-syscall-note" to its SPDX-License-Identifier. Update the "COMEDI DRIVERS" section of the MAINTAINERS file to account for these changes. Signed-off-by: Ian Abbott Link: https://lore.kernel.org/r/20211117120604.117740-2-abbotti@mev.co.uk Signed-off-by: Greg Kroah-Hartman