On Wed, Jul 03, 2019 at 07:33:58PM +0300, Alexander Shishkin wrote: > Greg Kroah-Hartman <gre...@linuxfoundation.org> writes: > > >> + /* > >> + * ->assign() called when buffer 'mode' is set to this driver > >> + * (aka mode_store()) > >> + * @device: struct device * of the msc > >> + * @mode: allows the driver to set HW mode (see the enum above) > >> + * Returns: a pointer to a private structure associated with this > >> + * msc or NULL in case of error. This private structure > >> + * will then be passed into all other callbacks. > >> + */ > >> + void *(*assign)(struct device *dev, int *mode); > >> + /* ->unassign(): some other mode is selected, clean up */ > >> + void (*unassign)(void *priv); > >> + /* > >> + * ->alloc_window(): allocate memory for the window of a given > >> + * size > >> + * @sgt: pointer to sg_table, can be overridden by the buffer > >> + * driver, or kept intact > >> + * Returns: number of sg table entries <= number of pages; > >> + * 0 is treated as an allocation failure. > >> + */ > >> + int (*alloc_window)(void *priv, struct sg_table **sgt, > >> + size_t size); > >> + void (*free_window)(void *priv, struct sg_table *sgt); > >> + /* ->activate(): trace has started */ > >> + void (*activate)(void *priv); > >> + /* ->deactivate(): trace is about to stop */ > >> + void (*deactivate)(void *priv); > >> + /* > >> + * ->ready(): window @sgt is filled up to the last block OR > >> + * tracing is stopped by the user; this window contains > >> + * @bytes data. The window in question transitions into > >> + * the "LOCKED" state, indicating that it can't be used > >> + * by hardware. To clear this state and make the window > >> + * available to the hardware again, call > >> + * intel_th_msc_window_unlock(). > >> + */ > >> + int (*ready)(void *priv, struct sg_table *sgt, size_t bytes); > >> +}; > > > > Why isn't this based off of 'struct driver'? > > It's not a real driver, in a sense that there's no underlying > device. None of the usual driver stuff applies.
Then do not call it a "driver", as in the kernel we have a very well-defined and known definition of a driver. Call it something else please. Yes, naming is hard, but don't try to overload onto an already existing name. > It's still a set of callbacks, though. Should this be an elaborate > comment, should I replace the word "driver" with something else? Yes. > I'd really like to avoid shoehorning the whole 'struct device' + > 'struct driver' here. Why not? If you have a driver, just make it a real one. It not take all that much boiler-plate code to do so and then you get all of the things you will want in the end anyway (sysfs representation, attributes, auto-loading of modules, etc.) Try doing it "for real" and see what happens. thanks, greg k-h
