* [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1
@ 2017-08-23 15:39 Colin King
2017-08-24 8:48 ` Aviad Krawczyk
2017-08-24 21:32 ` David Miller
0 siblings, 2 replies; 6+ messages in thread
From: Colin King @ 2017-08-23 15:39 UTC (permalink / raw)
To: Aviad Krawczyk, netdev; +Cc: kernel-janitors, linux-kernel
From: Colin Ian King <colin.king@canonical.com>
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@canonical.com>
---
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);
--
2.14.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1
2017-08-23 15:39 [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1 Colin King
@ 2017-08-24 8:48 ` Aviad Krawczyk
2017-08-24 8:54 ` Colin Ian King
2017-08-24 21:32 ` David Miller
1 sibling, 1 reply; 6+ messages in thread
From: Aviad Krawczyk @ 2017-08-24 8:48 UTC (permalink / raw)
To: Colin King, netdev; +Cc: kernel-janitors, linux-kernel
On 8/23/2017 6:39 PM, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> 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@canonical.com>
> ---
> 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;
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1
2017-08-24 8:48 ` Aviad Krawczyk
@ 2017-08-24 8:54 ` Colin Ian King
2017-08-24 9:29 ` Dan Carpenter
0 siblings, 1 reply; 6+ messages in thread
From: Colin Ian King @ 2017-08-24 8:54 UTC (permalink / raw)
To: Aviad Krawczyk, netdev; +Cc: kernel-janitors, linux-kernel
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@canonical.com>
>>
>> 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@canonical.com>
>> ---
>> 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?
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1
2017-08-24 8:54 ` Colin Ian King
@ 2017-08-24 9:29 ` Dan Carpenter
2017-08-24 9:38 ` Aviad Krawczyk
0 siblings, 1 reply; 6+ messages in thread
From: Dan Carpenter @ 2017-08-24 9:29 UTC (permalink / raw)
To: Colin Ian King; +Cc: Aviad Krawczyk, netdev, kernel-janitors, linux-kernel
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@canonical.com>
> >>
> >> 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@canonical.com>
> >> ---
> >> 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
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1
2017-08-24 9:29 ` Dan Carpenter
@ 2017-08-24 9:38 ` Aviad Krawczyk
0 siblings, 0 replies; 6+ messages in thread
From: Aviad Krawczyk @ 2017-08-24 9:38 UTC (permalink / raw)
To: Dan Carpenter, Colin Ian King; +Cc: netdev, kernel-janitors, linux-kernel
On 8/24/2017 12:29 PM, Dan Carpenter wrote:
> 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@canonical.com>
>>>>
>>>> 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@canonical.com>
>>>> ---
>>>> 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
>
>
> .
>
Hi Dan,
What if HINIC_RX_BUF_SZ is changed to another value?
The test checks if the HINIC_RX_BUF_SZ is in the table, if not return -EINVAL.
Therefore I think the check of rx_buf_sz_table[i].sz != HINIC_RX_BUF_SZ is better.
Aviad
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1
2017-08-23 15:39 [PATCH][next] net: hinic: fix comparison of a uint16_t type with -1 Colin King
2017-08-24 8:48 ` Aviad Krawczyk
@ 2017-08-24 21:32 ` David Miller
1 sibling, 0 replies; 6+ messages in thread
From: David Miller @ 2017-08-24 21:32 UTC (permalink / raw)
To: colin.king; +Cc: aviad.krawczyk, netdev, kernel-janitors, linux-kernel
From: Colin King <colin.king@canonical.com>
Date: Wed, 23 Aug 2017 16:39:36 +0100
> From: Colin Ian King <colin.king@canonical.com>
>
> 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@canonical.com>
> ---
> 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);
This is really silly.
The code in question is trying to convert a size (HINIC_RX_BUF_SZ)
into a table index, using a loop.
It should just compute this at compile time and do away with this
overly confusing code.
Even a switch statement would be much better and the compiler
would optimize the whole away into a single assignment in
the generated code.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2017-08-24 8:48 ` Aviad Krawczyk
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2017-08-24 9:29 ` Dan Carpenter
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