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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: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2013-01-09 13:30:22 -07:00 committed by Greg Kroah-Hartman
parent d21af4cbfb
commit 43f9137df4
1 changed files with 7 additions and 4 deletions
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11
drivers/staging/comedi/comedi_buf.c
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@ -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);