On Thu, Aug 24, 2017 at 09:54:03AM +0100, Colin Ian King wrote:
> On 24/08/17 09:48, Aviad Krawczyk wrote:
> > On 8/23/2017 6:39 PM, Colin King wrote:
> >> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >>
> >> The comparison of hw_ioctxt.rx_buf_sz_idx == -1 is always false because
> >> rx_buf_sz_idx is a uint16_t. Fix this by explicitly casting -1 to uint16_t.
> >>
> >> Detected by CoverityScan, CID#1454559 ("Operands don't affect result")
> >>
> >> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >> ---
> >> drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c b/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
> >> index 09dec6de8dd5..71e26070fb7f 100644
> >> --- a/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
> >> +++ b/drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
> >> @@ -352,7 +352,7 @@ static int set_hw_ioctxt(struct hinic_hwdev *hwdev, unsigned int rq_depth,
> >> }
> >> }
> >>
> >> - if (hw_ioctxt.rx_buf_sz_idx == -1)
> >> + if (hw_ioctxt.rx_buf_sz_idx == (uint16_t)-1)
> >> return -EINVAL;
> >>
> >> hw_ioctxt.sq_depth = ilog2(sq_depth);
> >>
> >
> > Many thanks, Colin.
> > I prefer to avoid casting when possible, what do you think about replacing the condition by:
> >
> > if (rx_buf_sz_table[i].sz != HINIC_RX_BUF_SZ)
> > return -EINVAL;
> >
>
> Does that work as expected when rx_buf_sz_table[i].sz == -1?
No it doesn't. Please, don't ask rhetorical questions. I have a
toddler and I constantly ask him toddler level questions and it drives
me nuts that all the adults in the room will answer me... "Yes, I
already know that's a cow. I was quizing my son. But thank you!"
Meanwhile I can't resist answering questions myself...
The code looks like this:
drivers/net/ethernet/huawei/hinic/hinic_hw_dev.c
345 hw_ioctxt.rq_depth = ilog2(rq_depth);
346
347 for (i = 0; ; i++) {
348 if ((rx_buf_sz_table[i].sz == HINIC_RX_BUF_SZ) ||
349 (rx_buf_sz_table[i].sz == -1)) {
350 hw_ioctxt.rx_buf_sz_idx = rx_buf_sz_table[i].idx;
351 break;
352 }
353 }
354
355 if (hw_ioctxt.rx_buf_sz_idx == -1)
356 return -EINVAL;
357
The loop doesn't make sense. We are looping through rx_buf_sz_table[]
until we hit 2048 or -1. But 2048 comes first so we always get there
and break.
We may as well replace all that code with:
hw_ioctxt.rx_buf_sz_idx = 11;
Something is very wrong.
regards,
dan carpenter
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