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Commit 43f9137d authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: comedi_buf: cleanup comedi_buf_read_n_available() 



For aesthetic reasons, cleanup this function a bit.

Change the (async == NULL) test to simply (!async).

Reword the comment about the need for the smp_rmb()..

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d21af4cb

drivers/staging/comedi/comedi_buf.c

+7 −4
Original line number Diff line number Diff line
@@ -273,14 +273,17 @@ unsigned int comedi_buf_read_n_available(struct comedi_async *async) 
{

	unsigned num_bytes;



	if (async == NULL)

	if (!async)

		return 0;



	num_bytes = async->munge_count - async->buf_read_count;

	/* barrier insures the read of munge_count in this

	   query occurs before any following reads of the buffer which

	   might be based on the return value from this query.



	/*

	 * ensure the async buffer 'counts' are read before we

	 * attempt to read data from the buffer

	 */

	smp_rmb();



	return num_bytes;

}

EXPORT_SYMBOL(comedi_buf_read_n_available);