Arnd Bergmann <a...@arndb.de> writes:
> The nb8800_poll() function initializes the 'next' variable in the
> loop looking for new input data. We know this will be called at
> least once because 'budget' is a guaranteed to be a positive number
> when we enter the function, but the compiler doesn't know that
> and warns when the variable is used later:
>
> drivers/net/ethernet/aurora/nb8800.c: In function 'nb8800_poll':
> drivers/net/ethernet/aurora/nb8800.c:350:21: warning: 'next' may be used
> uninitialized in this function [-Wmaybe-uninitialized]
Which gcc version is this? 4.9 doesn't warn here, presumably because
it's clever enough to notice that the offending use of 'next' is under a
condition that can only be true if the first one was. Of course fixing
the code so older compilers don't warn is a good idea.
> Changing the 'while() {}' loop to 'do {} while()' makes it obvious
> to the compiler what is going on so it no longer warns.
>
> Signed-off-by: Arnd Bergmann <a...@arndb.de>
Acked-by: Mans Rullgard <m...@mansr.com>
> ---
> drivers/net/ethernet/aurora/nb8800.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/aurora/nb8800.c
> b/drivers/net/ethernet/aurora/nb8800.c
> index ecc4a334c507..f71ab2647a3b 100644
> --- a/drivers/net/ethernet/aurora/nb8800.c
> +++ b/drivers/net/ethernet/aurora/nb8800.c
> @@ -302,7 +302,7 @@ static int nb8800_poll(struct napi_struct *napi, int
> budget)
> nb8800_tx_done(dev);
>
> again:
> - while (work < budget) {
> + do {
> struct nb8800_rx_buf *rxb;
> unsigned int len;
>
> @@ -330,7 +330,7 @@ again:
> rxd->report = 0;
> last = next;
> work++;
> - }
> + } while (work < budget);
>
> if (work) {
> priv->rx_descs[last].desc.config |= DESC_EOC;
> --
> 2.7.0
>
--
Måns Rullgård
