For aesthetic reasons, cleanup this function a bit. Change the (async == NULL) test to simply (!async). Add a comment about why the available number of bytes is modified by the modulus operator (%). Only space for full samples is returned. Cleanup the multi-line comment about the barrier. 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 | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index fe2dcae..a6b22c5 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -177,17 +177,22 @@ unsigned int comedi_buf_write_n_available(struct comedi_async *async) unsigned int free_end; unsigned int nbytes; - if (async == NULL) + if (!async) return 0; free_end = async->buf_read_count + async->prealloc_bufsz; nbytes = free_end - async->buf_write_alloc_count; + + /* don't allow partial samples */ nbytes -= nbytes % bytes_per_sample(async->subdevice); - /* barrier insures the read of buf_read_count in this - query occurs before any following writes to the buffer which - might be based on the return value from this query. + + /* + * barrier insures the read of buf_read_count above occurs + * before any following writes to the buffer which might + * be based on the return value from this query. */ smp_mb(); + return nbytes; } -- 1.8.0 _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
