Re: [PATCH] net: wan: wanxl.c: Cleaning up declaration of a while loop

From: Krzysztof Halasa
Date: Sat Jun 07 2014 - 13:48:36 EST


Rickard Strandqvist <rickard_strandqvist@xxxxxxxxxxxxxxxxxx> writes:

> Unusual declaration of a while loop.
> However, believe you also want to make sure that the pointer is not NULL

Not really. The code is meant to do exactly what it currently does -
set variable desc and then check desc->stat.
All rx_descs are at this point already initialized and not NULL
(if desc was indeed NULL we better BUG*() or Oops on desc->stat access
instead of failing silently).

> --- a/drivers/net/wan/wanxl.c
> +++ b/drivers/net/wan/wanxl.c
> @@ -196,7 +196,7 @@ static inline void wanxl_tx_intr(port_t *port)
> static inline void wanxl_rx_intr(card_t *card)
> {
> desc_t *desc;
> - while (desc = &card->status->rx_descs[card->rx_in],
> + while (desc = &card->status->rx_descs[card->rx_in] &&
> desc->stat != PACKET_EMPTY) {
> if ((desc->stat & PACKET_PORT_MASK) > card->n_ports)
> pr_crit("%s: received packet for nonexistent port\n",

--
Krzysztof Halasa
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