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Groups > linux.kernel > #1261511
| From | Geert Uytterhoeven <geert@linux-m68k.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack |
| Date | 2015-11-03 15:00 +0100 |
| Message-ID | <qqKhX-3qa-7@gated-at.bofh.it> (permalink) |
| References | <qqryF-8gz-17@gated-at.bofh.it> <qqzZg-56X-3@gated-at.bofh.it> <qqGHp-1jJ-23@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Nov 3, 2015 at 11:03 AM, Nikolay Aleksandrov
<nikolay@cumulusnetworks.com> wrote:
> On 11/03/2015 03:55 AM, Jarod Wilson wrote:
> [snip]
>>
>> +#define for_each_netdev_feature(mask_addr, feature) \
>> + int bit; \
>> + for_each_set_bit(bit, (unsigned long *)mask_addr, NETDEV_FEATURE_COUNT) \
>> + feature = __NETIF_F_BIT(bit);
>> +
> ^
> This is broken, it will not work for more than a single feature.
Indeed it is.
This is used as:
for_each_netdev_feature(&upper_disables, feature) {
...
}
which expands to:
int bit;
for_each_set_bit(bit, (unsigned long *)mask_addr, NETDEV_FEATURE_COUNT)
feature = __NETIF_F_BIT(bit);
{
...
}
Note the assignment to "feature" happens outside the {}-delimited block.
And the block is always executed once.
Interestingly, arm-unknown-linux-gnueabi-gcc 4.9.0 warns about this in
some of my configs, but not in all of them:
net/core/dev.c: In function '__netdev_update_features':
net/core/dev.c:6302:16: warning: 'feature' may be used uninitialized
in this function [-Wmaybe-uninitialized]
features &= ~feature;
^
net/core/dev.c:6295:20: note: 'feature' was declared here
netdev_features_t feature;
^
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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[PATCH net-next] net/core: generic support for disabling netdev features down stack Jarod Wilson <jarod@redhat.com> - 2015-11-02 19:00 +0100
Re: [PATCH net-next] net/core: generic support for disabling netdev features down stack Alexander Duyck <alexander.duyck@gmail.com> - 2015-11-02 19:10 +0100
Re: [PATCH net-next] net/core: generic support for disabling netdev features down stack Jarod Wilson <jarod@redhat.com> - 2015-11-02 23:00 +0100
[PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Jarod Wilson <jarod@redhat.com> - 2015-11-03 04:00 +0100
Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack David Miller <davem@davemloft.net> - 2015-11-03 05:50 +0100
Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Nikolay Aleksandrov <nikolay@cumulusnetworks.com> - 2015-11-03 11:10 +0100
Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Geert Uytterhoeven <geert@linux-m68k.org> - 2015-11-03 15:00 +0100
Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Jarod Wilson <jarod@redhat.com> - 2015-11-03 15:00 +0100
Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Nikolay Aleksandrov <nikolay@cumulusnetworks.com> - 2015-11-03 15:10 +0100
Re: [PATCH v2 net-next] net/core: generic support for disabling netdev features down stack Jarod Wilson <jarod@redhat.com> - 2015-11-03 17:10 +0100
[PATCH net-next] net/core: fix for_each_netdev_feature Jarod Wilson <jarod@redhat.com> - 2015-11-03 16:20 +0100
Re: [PATCH net-next] net/core: fix for_each_netdev_feature Nikolay Aleksandrov <nikolay@cumulusnetworks.com> - 2015-11-03 16:50 +0100
Re: [PATCH net-next] net/core: fix for_each_netdev_feature David Miller <davem@davemloft.net> - 2015-11-03 17:40 +0100
[PATCH net-next] net/core: ensure features get disabled on new lower devs Jarod Wilson <jarod@redhat.com> - 2015-11-03 21:40 +0100
Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs Alexander Duyck <alexander.duyck@gmail.com> - 2015-11-03 22:20 +0100
Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs Jarod Wilson <jarod@redhat.com> - 2015-11-03 23:20 +0100
Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs Alexander Duyck <alexander.duyck@gmail.com> - 2015-11-04 00:10 +0100
Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs Nikolay Aleksandrov <nikolay@cumulusnetworks.com> - 2015-11-03 22:30 +0100
Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs Michal Kubecek <mkubecek@suse.cz> - 2015-11-03 23:00 +0100
Re: [PATCH net-next] net/core: ensure features get disabled on new lower devs Jarod Wilson <jarod@redhat.com> - 2015-11-03 23:00 +0100
[PATCH v2 net-next] net/core: ensure features get disabled on new lower devs Jarod Wilson <jarod@redhat.com> - 2015-11-04 05:10 +0100
Re: [PATCH v2 net-next] net/core: ensure features get disabled on new lower devs David Miller <davem@davemloft.net> - 2015-11-05 04:00 +0100
Re: [PATCH v2 net-next] net/core: ensure features get disabled on new lower devs Florian Fainelli <f.fainelli@gmail.com> - 2015-11-13 01:30 +0100
Re: [PATCH v2 net-next] net/core: ensure features get disabled on new lower devs Jiri Pirko <jiri@resnulli.us> - 2015-11-13 11:30 +0100
Re: [PATCH v2 net-next] net/core: ensure features get disabled on new lower devs Nikolay Aleksandrov <nikolay@cumulusnetworks.com> - 2015-11-13 12:00 +0100
Re: [PATCH v2 net-next] net/core: ensure features get disabled on new lower devs Laura Abbott <labbott@redhat.com> - 2015-11-13 23:40 +0100
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