Clarify the check to make sure the number of bytes to allocate is available.
Also, cleanup the multi-line comment about the barrier. Signed-off-by: H Hartley Sweeten <[email protected]> Cc: Ian Abbott <[email protected]> Cc: Greg Kroah-Hartman <[email protected]> --- drivers/staging/comedi/comedi_buf.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index a12b70b..a95bb3d 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -293,14 +293,19 @@ EXPORT_SYMBOL(comedi_buf_read_n_available); /* allocates a chunk for the reader from filled (and munged) buffer space */ unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes) { - if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) > - 0) { - nbytes = async->munge_count - async->buf_read_alloc_count; - } + unsigned int available = async->munge_count - async->buf_read_alloc_count; + + if (nbytes > available) + nbytes = available; + async->buf_read_alloc_count += nbytes; - /* barrier insures read of munge_count occurs before we actually read - data out of buffer */ + + /* + * barrier insures the read of munge_count above occurs + * before any following reads out of the buffer + */ smp_rmb(); + return nbytes; } EXPORT_SYMBOL(comedi_buf_read_alloc); -- 1.8.0 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
