Commit 432fbde7 authored by Ian Abbott's avatar Ian Abbott Committed by Greg Kroah-Hartman
Browse files

staging: comedi: add new comedi_buf_write_n_available() 



Add a new function `comedi_buf_write_n_available()` to return the amount
of buffer space available for writing, including space already allocated
by `comedi_buf_write_alloc()` plus any unallocated space available.
This is currently just for internal use by the comedi core, so is not
exported.

Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Reviewed-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 274ec5ee

drivers/staging/comedi/comedi_buf.c

+8 −0
Original line number Diff line number Diff line
@@ -253,6 +253,14 @@ static unsigned int comedi_buf_write_n_unalloc(struct comedi_subdevice *s) 
	return free_end - async->buf_write_alloc_count;

}



unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s)

{

	struct comedi_async *async = s->async;

	unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;



	return free_end - async->buf_write_count;

}



/**

 * comedi_buf_write_alloc() - Reserve buffer space for writing

 * @s: COMEDI subdevice.

drivers/staging/comedi/comedi_internal.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ void comedi_buf_map_get(struct comedi_buf_map *bm); 
int comedi_buf_map_put(struct comedi_buf_map *bm);

struct comedi_buf_map *comedi_buf_map_from_subdev_get(

		struct comedi_subdevice *s);

unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s);

unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s);

void comedi_device_cancel_all(struct comedi_device *dev);

bool comedi_can_auto_free_spriv(struct comedi_subdevice *s);

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