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@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbobbi@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/comedi_buf.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
index fd2a92e..06dd544 100644
--- a/drivers/staging/comedi/comedi_buf.c
+++ b/drivers/staging/comedi/comedi_buf.c
@@ -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);
--
1.8.0
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