Clarify the check to make sure the number of bytes to free is not more than the number of bytes allocated.
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 | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index a95bb3d..eefd49f 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -313,14 +313,19 @@ EXPORT_SYMBOL(comedi_buf_read_alloc); /* transfers control of a chunk from reader to free buffer space */ unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes) { - /* barrier insures data has been read out of - * buffer before read count is incremented */ + unsigned int allocated; + + /* + * barrier insures data has been read out of the + * buffer before read count is incremented + */ smp_mb(); - if ((int)(async->buf_read_count + nbytes - - async->buf_read_alloc_count) > 0) { + + allocated = async->buf_read_alloc_count - async->buf_read_count; + if (nbytes > allocated) { dev_info(async->subdevice->device->class_dev, "attempted to read-free more bytes than have been read-allocated.\n"); - nbytes = async->buf_read_alloc_count - async->buf_read_count; + nbytes = allocated; } async->buf_read_count += nbytes; async->buf_read_ptr += nbytes; -- 1.8.0 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
