Clarify the check to make sure the number of bytes to free is not more than the number of bytes allocated.
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 | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c index 5e08266..246f577 100644 --- a/drivers/staging/comedi/comedi_buf.c +++ b/drivers/staging/comedi/comedi_buf.c @@ -313,14 +313,16 @@ 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) { + unsigned allocated; + /* barrier insures data has been read out of * buffer before read count is incremented */ smp_mb(); - if ((int)(async->buf_read_count + nbytes - - async->buf_read_alloc_count) > 0) { + allocated = comedi_buf_read_n_allocated(async); + 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
