* Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's
From: Doug Ledford @ 2013-10-30 13:22 UTC (permalink / raw)
To: David Laight, Neil Horman; +Cc: Ingo Molnar, Eric Dumazet, linux-kernel, netdev
In-Reply-To: <AE90C24D6B3A694183C094C60CF0A2F6026B73C5@saturn3.aculab.com>
On 10/30/2013 08:18 AM, David Laight wrote:
>> /me wonders if rearranging the instructions into this order:
>> adcq 0*8(src), res1
>> adcq 1*8(src), res2
>> adcq 2*8(src), res1
>
> Those have to be sequenced.
>
> Using a 64bit lea to add 32bit quantities should avoid the
> dependencies on the flags register.
> However you'd need to get 3 of those active to beat a 64bit adc.
>
> David
>
>
>
Already done (well, something similar to what you mention above anyway),
doesn't help (although doesn't hurt either, even though it doubles the
number of adds needed to complete the same work). This is the code I
tested:
#define ADDL_64 \
asm("xorq %%r8,%%r8\n\t" \
"xorq %%r9,%%r9\n\t" \
"xorq %%r10,%%r10\n\t" \
"xorq %%r11,%%r11\n\t" \
"movl 0*4(%[src]),%%r8d\n\t" \
"movl 1*4(%[src]),%%r9d\n\t" \
"movl 2*4(%[src]),%%r10d\n\t" \
"movl 3*4(%[src]),%%r11d\n\t" \
"addq %%r8,%[res1]\n\t" \
"addq %%r9,%[res2]\n\t" \
"addq %%r10,%[res3]\n\t" \
"addq %%r11,%[res4]\n\t" \
"movl 4*4(%[src]),%%r8d\n\t" \
"movl 5*4(%[src]),%%r9d\n\t" \
"movl 6*4(%[src]),%%r10d\n\t" \
"movl 7*4(%[src]),%%r11d\n\t" \
"addq %%r8,%[res1]\n\t" \
"addq %%r9,%[res2]\n\t" \
"addq %%r10,%[res3]\n\t" \
"addq %%r11,%[res4]\n\t" \
"movl 8*4(%[src]),%%r8d\n\t" \
"movl 9*4(%[src]),%%r9d\n\t" \
"movl 10*4(%[src]),%%r10d\n\t" \
"movl 11*4(%[src]),%%r11d\n\t" \
"addq %%r8,%[res1]\n\t" \
"addq %%r9,%[res2]\n\t" \
"addq %%r10,%[res3]\n\t" \
"addq %%r11,%[res4]\n\t" \
"movl 12*4(%[src]),%%r8d\n\t" \
"movl 13*4(%[src]),%%r9d\n\t" \
"movl 14*4(%[src]),%%r10d\n\t" \
"movl 15*4(%[src]),%%r11d\n\t" \
"addq %%r8,%[res1]\n\t" \
"addq %%r9,%[res2]\n\t" \
"addq %%r10,%[res3]\n\t" \
"addq %%r11,%[res4]" \
: [res1] "=r" (result1), \
[res2] "=r" (result2), \
[res3] "=r" (result3), \
[res4] "=r" (result4) \
: [src] "r" (buff), \
"[res1]" (result1), "[res2]" (result2), \
"[res3]" (result3), "[res4]" (result4) \
: "r8", "r9", "r10", "r11" )
^ permalink raw reply
* Re: 3.12-rc7 regression - network panic from ipv6
From: Steffen Klassert @ 2013-10-30 13:09 UTC (permalink / raw)
To: David Miller; +Cc: mroos, hannes, linux-kernel, netdev
In-Reply-To: <20131029.174258.1677867676998240250.davem@davemloft.net>
On Tue, Oct 29, 2013 at 05:42:58PM -0400, David Miller wrote:
> From: Meelis Roos <mroos@linux.ee>
> Date: Tue, 29 Oct 2013 23:38:28 +0200 (EET)
>
> >> > Some bad news - in a system where 3.12-rc6 and earlier worked fine,
> >> > 3.12-rc7 panics or hangs repeatedly with network traffic (torrent being
> >> > good test). First there is BUG from ipv6 code, followed by panic.
> >>
> >> Could you do a bisect on this? There seems to be one commit for this
> >> particular function _decode_session6:
> >>
> >> commit bafd4bd4dcfa13145db7f951251eef3e10f8c278
> >> Author: Steffen Klassert <steffen.klassert@secunet.com>
> >> Date: Mon Sep 9 10:38:38 2013 +0200
> >>
> >> xfrm: Decode sessions with output interface.
> >>
> >> The output interface matching does not work on forward
> >> policy lookups, the output interface of the flowi is
> >> always 0. Fix this by setting the output interface when
> >> we decode the session.
> >>
> >> Maybe try to just revert this change locally and try again?
> >
> > Yes, just reverting this patch on top of rc7 gets rid of the problem for
> > me.
>
> Steffen please fix this or I'll have to revert.
I was a bit surprised that the skb has no dst_entry attached.
But in the reported case, ip6_frag_queue() removes the dst_entry
explicitly on all but the last received fragments. And unlike the
ipv4 case, it does not restore it before ip6_expire_frag_queue()
calls icmpv6_send().
I'm currently testing the patch below. Meelis, could you please
check if this patch fixes your problems?
Unfortunately I'm off without network access for the whole day
tomorrow. So in case the patch fixes the problems, I'd integrate it
into the final ipsec pull request for this release cycle on friday.
Subject: [PATCH] xfrm: Fix null pointer dereference when decoding sessions
On some codepaths the skb does not have a dst entry
when xfrm_decode_session() is called. So check for
a valid skb_dst() before dereferencing the device
interface index. We use 0 as the device index if
there is no valid skb_dst(), or at reverse decoding
we use skb_iif as device interface index.
Bug was introduced with git commit bafd4bd4dc
("xfrm: Decode sessions with output interface.").
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
---
net/ipv4/xfrm4_policy.c | 6 +++++-
net/ipv6/xfrm6_policy.c | 6 +++++-
2 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 4764ee4..e1a6393 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -104,10 +104,14 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
const struct iphdr *iph = ip_hdr(skb);
u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
struct flowi4 *fl4 = &fl->u.ip4;
+ int oif = 0;
+
+ if (skb_dst(skb))
+ oif = skb_dst(skb)->dev->ifindex;
memset(fl4, 0, sizeof(struct flowi4));
fl4->flowi4_mark = skb->mark;
- fl4->flowi4_oif = skb_dst(skb)->dev->ifindex;
+ fl4->flowi4_oif = reverse ? skb->skb_iif : oif;
if (!ip_is_fragment(iph)) {
switch (iph->protocol) {
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index dd503a3..5f8e128 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -135,10 +135,14 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
struct ipv6_opt_hdr *exthdr;
const unsigned char *nh = skb_network_header(skb);
u8 nexthdr = nh[IP6CB(skb)->nhoff];
+ int oif = 0;
+
+ if (skb_dst(skb))
+ oif = skb_dst(skb)->dev->ifindex;
memset(fl6, 0, sizeof(struct flowi6));
fl6->flowi6_mark = skb->mark;
- fl6->flowi6_oif = skb_dst(skb)->dev->ifindex;
+ fl6->flowi6_oif = reverse ? skb->skb_iif : oif;
fl6->daddr = reverse ? hdr->saddr : hdr->daddr;
fl6->saddr = reverse ? hdr->daddr : hdr->saddr;
--
1.7.9.5
^ permalink raw reply related
* Re: [PATCH 1/4 net-next] net: phy: add Generic Netlink Ethernet switch configuration API
From: Felix Fietkau @ 2013-10-30 12:53 UTC (permalink / raw)
To: Jamal Hadi Salim, Florian Fainelli, Neil Horman
Cc: John Fastabend, netdev, David Miller, Sascha Hauer, John Crispin,
Jonas Gorski, Gary Thomas, Vlad Yasevich, Stephen Hemminger
In-Reply-To: <5270F161.80603@mojatatu.com>
On 2013-10-30 12:45, Jamal Hadi Salim wrote:
> On 10/29/13 05:34, Felix Fietkau wrote:
>> On 2013-10-28 23:53, Jamal Hadi Salim wrote:
>
>>
>> These are simple switches, why would they respond to ARP?
>> I suspect that you're attributing too much functionality to the switch
>> itself. Think of it as a device similar to the cheap unmanaged ones you
>> can buy in a shop and hook up to your machine via Ethernet.
>> Add to that some very limited VLAN grouping functionality, and you're
>> pretty close to the limits of what these switches can do.
>> They don't do ARP, IP or other things. They learn about MAC addresses
>> from incoming packets to build their forwarding path.
>> The CPU port in this case is whatever port on the switch that you plug
>> the cable of your machine into :)
>
> Ok, got it - the only use for cpu for these things is to retrieve things
> like stats, link state, etc; can you even read the fdb?
Where supported, all you can typically read is a list of which MAC
address was discovered behind which port - if you're lucky. You usually
won't find VLAN information attached to that.
Often it simply isn't supported at all.
>> The FDB related abstraction that you're describing will not work with
>> the hardware that I'm talking about. Let's leave that one out of this
>> discussion.
>
> sigh - ok. But you gotta help me understand why.
The hardware implementation of MAC address handling isn't even
consistent across chips from different vendors. Often you don't even get
things like the VLAN ID. Sometimes there's a global forwarding table,
sometimes you can have multiple tables and assign them to VLANs.
>>> Can we call that "L3" instead of software bridge?
>> L3? Why?
>
> We have two L2 domains. You want to connect them - you need a higher
> layer; Layer 3 seems to be the simple one (i.e typically people would
> use ip to link two layer 2 broadcast domains).
If you connect two L2 domains through a bridge, I still consider that L2
- it's still on the same layer, just goes through more hops.
>> I think that's way more confusing to users than presenting a consistent
>> model that properly reflects what you can do with the hardware.
> I think discovery from a control view is always a win.
Yes, and swconfig handles the discovery part fairly well.
>> I'm not going to try to enumerate all the case; I have other projects
>> that I need to work on. :)
>
> I understand. I am busy as well, just saying if we need to reach an
> agreement to either agree or disagree we need to capture the esoterics
> of the different cases; as you can see i tried to enumerate some in
> my previous email. In my case this would be useful to see, using current
> mechanisms, that it can or cant be done or can be done with mods etc.
At this point, I'm not sure if we will be able to reach an agreement. I
think I've shown over and over again that what you're proposing comes
with huge costs in terms of complexity and bloat, as demonstrated by the
fact that it adds so many corner cases that would have to be dealt with,
including many for which we haven't even the slightest idea of a good
solution.
Now, to make this a viable option, the benefits would have to be big and
significant enough to offset these costs.
The only real benefit you've pointed out so far is to be able to reuse
existing tools/APIs (but only with modifications, not as-is). I think
that's fairly small, when put in perspective with the hard problems that
this approach creates, both for users (hidden traps and surprises) and
for developers (implementation difficulties and incompatible abstractions).
>> Only a *tiny* part of the software bridge configuration model can be
>> emulated, the rest does not fit and has to be handled through extensions
>> or different APIs anyway. That's why I am convinced that it's a really
>> bad model to try to make these switches fit into it.
>>
>> You gain a tiny advantage with writing scripts, but at the same time,
>> the code gets more complex, the configuration interface gets more
>> confusing, there are more nasty corner cases to take care of.
>> Why do you insist on making so many things worse just for one tiny
>> advantage? Where's the pragmatic cost/benefit tradeoff?
>>
>
> There is nothing wrong with making extensions if they make sense.
Yes, but if the basic abstraction doesn't make sense for the use case,
and it leads to too many corner cases, there's everything wrong with
trying to work around that through extensions.
> My problem so far in this discussion is i havent figured which will be bad
> extensions you bring up. My approach is to list things and
> then point out which one will require some witchcraft on top of
> current interfaces. I am afraid I am still missing that part. Maybe
> I have to go back and study your patch some more.
Sure, go ahead.
>> On pretty much all devices that we work with, one of the ports
>> connects to a NIC in the CPU. It's just that the switch cannot be
>> assumed to have special treatment for that CPU port. As far as it is
>> concerned, it is just another port like the others.
>
> Aha. I think i see a small terminology cross-talk. You refer to things
> as NICs when i use the term netdev. So now i understand better what you
> mean by rx handler (I intepreted earlier to mean something at the tap
> level).
I only started using the term NIC to emphasize that it's not just a
netdev of the switch - it's a real Ethernet MAC (usually in the SoC),
with a separate driver that knows nothing about the switch.
> Ok, so Felix, for the case where we have switches with cpu ports
> that can tag incoming packets with ingress port ids - can we say the
> NIC rx handler is reasonable to be used as a demux point for the
> software version of the ports? I am not talking about the corner
> cases.
Yes, but when looking at the big picture, the switch being able to tag
incoming packets with the ingress port is a corner case!
Most switches that we work with aren't actually able to do that!
I want to have a decent baseline implementation that does not assume
this port tagging capability.
>>> - ive never seen table id, but i think this is another one; in which
>>> case the number of table ids becomes something one needs to discover..
>> Yes, and this is something that doesn't even map directly to something
>> in the software bridge world.
> It does - There is a single table per bridge on the software bridge
> world. You need multiple bridges, one per id.
Depends on which software bridge.
If I have two normal netdevs, eth0 and eth1, I can create eth0.4 and
bridge it to eth1.5. That's just one bridge.
I can't easily emulate that with fake per-port netdevs and a typical
switch supported by swconfig.
With just swconfig (no fake netdevs) switches that support these table
ids, I would need to have two VLANs in the switch (both connected to the
CPU port, each one getting a separate table id), and then one software
bridge between eth0.4 and eth0.5 (assuming eth0 connects to the switch).
- Felix
^ permalink raw reply
* RE: [PATCH] x86: Run checksumming in parallel accross multiple alu's
From: David Laight @ 2013-10-30 12:18 UTC (permalink / raw)
To: Neil Horman, Doug Ledford; +Cc: Ingo Molnar, Eric Dumazet, linux-kernel, netdev
In-Reply-To: <20131030110214.GA10220@localhost.localdomain>
> /me wonders if rearranging the instructions into this order:
> adcq 0*8(src), res1
> adcq 1*8(src), res2
> adcq 2*8(src), res1
Those have to be sequenced.
Using a 64bit lea to add 32bit quantities should avoid the
dependencies on the flags register.
However you'd need to get 3 of those active to beat a 64bit adc.
David
^ permalink raw reply
* Re: [PATCH 1/4 net-next] net: phy: add Generic Netlink Ethernet switch configuration API
From: Felix Fietkau @ 2013-10-30 11:58 UTC (permalink / raw)
To: Jamal Hadi Salim, mbizon
Cc: Florian Fainelli, Neil Horman, John Fastabend, netdev,
David Miller, Sascha Hauer, John Crispin, Jonas Gorski,
Gary Thomas, Vlad Yasevich, Stephen Hemminger
In-Reply-To: <5270F282.6000708@mojatatu.com>
On 2013-10-30 12:50, Jamal Hadi Salim wrote:
> On 10/29/13 19:12, Maxime Bizon wrote:
>
>>
>> From a user POV, when you see a netdevice, you expect to be able to
>> receive or send packets from/to it. The ability to read stats/link is
>> only a secondary feature.
>>
>
> The important part is all the APIs stay consistent. I can use
> same netlink calls. ifconfig works.
> iproute2 works. People have written books on this stuff - we dont
> have MCSE(Must Call Software Engineer) certification, but this is
> as close as it gets. i.e the knowledge has been commoditized, even
> my kid knows how to use these tools.
>
> If i can get stats by doing ifconfig - that should provide illusion that
> the netdevice is sending/receiving packets.
Pretty much all of the above have serious limitations when you're not
actually able to run the data path through the per-port netdevs.
You can't assign IP addresses to them. The network stack will probably
even attempt to assign IPv6 link-local addresses to these things,
causing even more confusion.
You can't add them to normal software bridges like other devices.
You can't use bonding. I could probably go on for a while.
There's a huge list of things that you simply cannot do with these
interfaces, and without knowing the details of the implementation, users
will be left clueless as to why that is.
I'd say that's a very serious violation of the principle of least surprise.
And knowing what the typical OpenWrt users do with their devices, I can
already forsee the bogus bug reports trickling in, if this is to be
implemented.
- Felix
^ permalink raw reply
* Re: [PATCH 14/16] wl1251: add nvs file name to module firmware list
From: Pavel Machek @ 2013-10-30 11:55 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen
In-Reply-To: <1382819655-30430-15-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:13, Pali Rohár wrote:
> Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Reviewed-by: Pavel Machek <pavel@ucw.cz>
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 13/16] wl1251: enforce changed hw encryption support on monitor state change
From: Pavel Machek @ 2013-10-30 11:55 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-14-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:12, Pali Rohár wrote:
> From: David Gnedt <david.gnedt@davizone.at>
>
> The firmware doesn't support per packet encryption selection, so disable hw
> encryption support completly while a monitor interface is present to support
"completely".
> injection of packets (which shouldn't get encrypted by hw).
> To enforce the changed hw encryption support force a disassociation on
> non-monitor interfaces.
> For disassociation a workaround using hw connection monitor is employed,
> which temporary enables hw connection manager flag.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
Missing sign-off.
> index 174f403..f054741 100644
> --- a/drivers/net/wireless/ti/wl1251/main.c
> +++ b/drivers/net/wireless/ti/wl1251/main.c
> @@ -685,6 +685,16 @@ static int wl1251_op_config(struct ieee80211_hw *hw, u32 changed)
> wl->power_level = conf->power_level;
> }
>
> + /*
> + * Tell stack that connection is lost because hw encryption isn't
> + * supported in monitor mode.
> + * XXX This requires temporary enabling the hw connection monitor flag
> + */
"of the" and I guess you can remove the XXX? This way it looks like
workaround is not complete.
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 12/16] wl1251: disable retry and ACK policy for injected packets
From: Pavel Machek @ 2013-10-30 11:52 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-13-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:11, Pali Rohár wrote:
> From: David Gnedt <david.gnedt@davizone.at>
>
> Set the retry limit to 0 and disable the ACK policy for injected packets.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
Missing sign-off, otherwise ok:
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 11/16] wl1251: enable tx path in monitor mode if necessary for packet injection
From: Pavel Machek @ 2013-10-30 11:51 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-12-git-send-email-pali.rohar@gmail.com>
Hi!
>
> If necessary enable the tx path in monitor mode for packet injection using
> the JOIN command with BSS_TYPE_STA_BSS and zero BSSID.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
> ---
> drivers/net/wireless/ti/wl1251/main.c | 5 +++++
> drivers/net/wireless/ti/wl1251/tx.c | 17 +++++++++++++++++
> drivers/net/wireless/ti/wl1251/wl1251.h | 1 +
> 3 files changed, 23 insertions(+)
>
> diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c
> diff --git a/drivers/net/wireless/ti/wl1251/tx.c b/drivers/net/wireless/ti/wl1251/tx.c
> index 3cc82fd..1de4ccb 100644
> --- a/drivers/net/wireless/ti/wl1251/tx.c
> +++ b/drivers/net/wireless/ti/wl1251/tx.c
> @@ -28,6 +28,7 @@
> #include "tx.h"
> #include "ps.h"
> #include "io.h"
> +#include "event.h"
>
> static bool wl1251_tx_double_buffer_busy(struct wl1251 *wl, u32 data_out_count)
> {
> @@ -298,6 +299,22 @@ static int wl1251_tx_frame(struct wl1251 *wl, struct sk_buff *skb)
> }
> }
>
> + /* Enable tx path in monitor mode for packet injection */
> + if ((wl->vif == NULL) && !wl->joined) {
> + ret = wl1251_cmd_join(wl, BSS_TYPE_STA_BSS, wl->channel,
> + wl->beacon_int, wl->dtim_period);
> + if (ret < 0)
> + wl1251_warning("join failed");
> + else {
> + ret = wl1251_event_wait(wl, JOIN_EVENT_COMPLETE_ID,
> + 100);
> + if (ret < 0)
> + wl1251_warning("join timeout");
> + else
> + wl->joined = true;
> + }
> + }
Create function enable_tx_for_packet_injection() and then just return
so that you don't have to nest ifs?
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 1/4 net-next] net: phy: add Generic Netlink Ethernet switch configuration API
From: Jamal Hadi Salim @ 2013-10-30 11:50 UTC (permalink / raw)
To: mbizon
Cc: Felix Fietkau, Florian Fainelli, Neil Horman, John Fastabend,
netdev, David Miller, Sascha Hauer, John Crispin, Jonas Gorski,
Gary Thomas, Vlad Yasevich, Stephen Hemminger
In-Reply-To: <1383088365.16822.22.camel@sakura.staff.proxad.net>
On 10/29/13 19:12, Maxime Bizon wrote:
>
> From a user POV, when you see a netdevice, you expect to be able to
> receive or send packets from/to it. The ability to read stats/link is
> only a secondary feature.
>
The important part is all the APIs stay consistent. I can use
same netlink calls. ifconfig works.
iproute2 works. People have written books on this stuff - we dont
have MCSE(Must Call Software Engineer) certification, but this is
as close as it gets. i.e the knowledge has been commoditized, even
my kid knows how to use these tools.
If i can get stats by doing ifconfig - that should provide illusion that
the netdevice is sending/receiving packets.
> Wireless subsystem moved away from using dummy/additional netdevices
> because it caused confusion.
>
This is a good arguement.
Can we hear a little more about this?
> multiqueue devices forced us to separate struct netdevice and struct
> netdev_queue, maybe it's time for more surgery :)
>
I think that would be a reasonable thing to do if it becomes necessary.
cheers,
jamal
^ permalink raw reply
* Re: [PATCH 10/16] wl1251: fix channel switching in monitor mode
From: Pavel Machek @ 2013-10-30 11:47 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-11-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:09, Pali Rohár wrote:
> From: David Gnedt <david.gnedt@davizone.at>
>
> Use the ENABLE_RX command for channel switching when no interface is present
> (monitor mode only).
> The advantage of ENABLE_RX is that it leaves the tx data path disabled in
> firmware, whereas the usual JOIN command seems to transmit some frames at
> firmware level.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
Missing signoff, otherwise
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 09/16] wl1251: disable power saving in monitor mode
From: Pavel Machek @ 2013-10-30 11:46 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-10-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:08, Pali Rohár wrote:
> From: David Gnedt <david.gnedt@davizone.at>
>
> Force power saving off while monitor interface is present.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
> ---
> drivers/net/wireless/ti/wl1251/main.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c
> index 727f2ee..62cb374 100644
> --- a/drivers/net/wireless/ti/wl1251/main.c
> +++ b/drivers/net/wireless/ti/wl1251/main.c
> @@ -617,7 +617,8 @@ static int wl1251_op_config(struct ieee80211_hw *hw, u32 changed)
> goto out_sleep;
> }
>
> - if (conf->flags & IEEE80211_CONF_PS && !wl->psm_requested) {
> + if (conf->flags & IEEE80211_CONF_PS && !wl->psm_requested &&
> + !wl->monitor_present) {
> wl1251_debug(DEBUG_PSM, "psm enabled");
>
> wl->psm_requested = true;
> @@ -633,8 +634,8 @@ static int wl1251_op_config(struct ieee80211_hw *hw, u32 changed)
> ret = wl1251_ps_set_mode(wl, STATION_POWER_SAVE_MODE);
> if (ret < 0)
> goto out_sleep;
> - } else if (!(conf->flags & IEEE80211_CONF_PS) &&
> - wl->psm_requested) {
> + } else if ((!(conf->flags & IEEE80211_CONF_PS) || wl->monitor_present)
> + && wl->psm_requested) {
> wl1251_debug(DEBUG_PSM, "psm disabled");
>
These boolean expressions make my head spin. Introduce helper function
can_do_pm()... return (conf->flags & IEEE80211_CONF_PS) &&
!wl->monitor_present
?
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 1/4 net-next] net: phy: add Generic Netlink Ethernet switch configuration API
From: Jamal Hadi Salim @ 2013-10-30 11:45 UTC (permalink / raw)
To: Felix Fietkau, Florian Fainelli, Neil Horman
Cc: John Fastabend, netdev, David Miller, Sascha Hauer, John Crispin,
Jonas Gorski, Gary Thomas, Vlad Yasevich, Stephen Hemminger
In-Reply-To: <526F8118.50909@openwrt.org>
On 10/29/13 05:34, Felix Fietkau wrote:
> On 2013-10-28 23:53, Jamal Hadi Salim wrote:
>
> These are simple switches, why would they respond to ARP?
> I suspect that you're attributing too much functionality to the switch
> itself. Think of it as a device similar to the cheap unmanaged ones you
> can buy in a shop and hook up to your machine via Ethernet.
> Add to that some very limited VLAN grouping functionality, and you're
> pretty close to the limits of what these switches can do.
> They don't do ARP, IP or other things. They learn about MAC addresses
> from incoming packets to build their forwarding path.
> The CPU port in this case is whatever port on the switch that you plug
> the cable of your machine into :)
Ok, got it - the only use for cpu for these things is to retrieve things
like stats, link state, etc; can you even read the fdb?
> The FDB related abstraction that you're describing will not work with
> the hardware that I'm talking about. Let's leave that one out of this
> discussion.
sigh - ok. But you gotta help me understand why.
> As for per-port netdevs: Yes, you could pull stats.
> No, flow control messages would not make it through.
> No idea how it would provide a *consistent* API.
> Either way, if adding netdevs just for stats and link state, that could
> be easily added on top of swconfig (or whatever name we pick for it)
> later. I just don't think it's worth it at this point.
>
Ok, progress, lets leave this one out.
>> Can we call that "L3" instead of software bridge?
> L3? Why?
We have two L2 domains. You want to connect them - you need a higher
layer; Layer 3 seems to be the simple one (i.e typically people would
use ip to link two layer 2 broadcast domains).
> I think that's way more confusing to users than presenting a consistent
> model that properly reflects what you can do with the hardware.
>
I think discovery from a control view is always a win.
> But I sense a pattern here. I've long had my beef with quite a few Linux
> network related APIs for being inconsistent, having no decent error
> reporting when you're trying to configure things (errno doesn't count,
> it's just too ambiguous), and just making it hard to figure out the
> capabilities. Of course, none of this can be easily fixed due to ABI
> stability constraints.
> I do NOT wish to follow that pattern!
>
You are preaching to the choir. The whole errno 8 bit thing is a mess;
I used to printk things in the kernel to indicate granularity of
which EINVAL i was returning (but i was shot down); one suggestion is
to also include a string description on the error. But that is a side
issue.
So, nod. Discovery of capabilities is better - you still have to defer
to error codes when all else fails.
> I'm not going to try to enumerate all the case; I have other projects
> that I need to work on. :)
>
I understand. I am busy as well, just saying if we need to reach an
agreement to either agree or disagree we need to capture the esoterics
of the different cases; as you can see i tried to enumerate some in
my previous email. In my case this would be useful to see, using current
mechanisms, that it can or cant be done or can be done with mods etc.
> Only a *tiny* part of the software bridge configuration model can be
> emulated, the rest does not fit and has to be handled through extensions
> or different APIs anyway. That's why I am convinced that it's a really
> bad model to try to make these switches fit into it.
>
> You gain a tiny advantage with writing scripts, but at the same time,
> the code gets more complex, the configuration interface gets more
> confusing, there are more nasty corner cases to take care of.
> Why do you insist on making so many things worse just for one tiny
> advantage? Where's the pragmatic cost/benefit tradeoff?
>
There is nothing wrong with making extensions if they make sense. My
problem so far in this discussion is i havent figured which will be bad
extensions you bring up. My approach is to list things and
then point out which one will require some witchcraft on top of
current interfaces. I am afraid I am still missing that part. Maybe
I have to go back and study your patch some more.
> Right, with most of the switches that we support, almost none of these
> things work in a way that can be integrated with the network stack.
>
Good to know. These are useful components for slightly higher end
switches.
> I'm not even sure what you mean when you say 'cpu port cannot be
> assumed'.
Meant for other devices which are dumb - lets move past this point.
> On pretty much all devices that we work with, one of the ports
> connects to a NIC in the CPU. It's just that the switch cannot be
> assumed to have special treatment for that CPU port. As far as it is
> concerned, it is just another port like the others.
>
Aha. I think i see a small terminology cross-talk. You refer to things
as NICs when i use the term netdev. So now i understand better what you
mean by rx handler (I intepreted earlier to mean something at the tap
level). Ok, so Felix, for the case where we have switches with cpu ports
that can tag incoming packets with ingress port ids - can we say the
NIC rx handler is reasonable to be used as a demux point for the
software version of the ports? I am not talking about the corner
cases.
>> - ive never seen table id, but i think this is another one; in which
>> case the number of table ids becomes something one needs to discover..
> Yes, and this is something that doesn't even map directly to something
> in the software bridge world.
>
It does - There is a single table per bridge on the software bridge
world. You need multiple bridges, one per id.
cheers,
jamal
^ permalink raw reply
* Re: [PATCH 08/16] wl1251: implement multicast address filtering
From: Pavel Machek @ 2013-10-30 11:41 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-9-git-send-email-pali.rohar@gmail.com>
Hi!
> Port multicast address filtering from wl1271 driver.
> It sets up the hardware multicast address filter in configure_filter() with
> addresses supplied through prepare_multicast().
> +static u64 wl1251_op_prepare_multicast(struct ieee80211_hw *hw,
> + struct netdev_hw_addr_list *mc_list)
> +{
> + struct wl1251_filter_params *fp;
> + struct netdev_hw_addr *ha;
> + struct wl1251 *wl = hw->priv;
> +
> + if (unlikely(wl->state == WL1251_STATE_OFF))
> + return 0;
> +
> + fp = kzalloc(sizeof(*fp), GFP_ATOMIC);
> + if (!fp) {
> + wl1251_error("Out of memory setting filters.");
> + return 0;
> + }
So if there's not enough memory, we return 0.
> + /* update multicast filtering parameters */
> + fp->mc_list_length = 0;
> + if (netdev_hw_addr_list_count(mc_list) > ACX_MC_ADDRESS_GROUP_MAX) {
> + fp->enabled = false;
> + } else {
> + fp->enabled = true;
> + netdev_hw_addr_list_for_each(ha, mc_list) {
> + memcpy(fp->mc_list[fp->mc_list_length],
> + ha->addr, ETH_ALEN);
> + fp->mc_list_length++;
> + }
> + }
> +
> + return (u64)(unsigned long)fp;
> +}
Hiding pointers into u64 is not exactly nice, but I guess that's how
interface is designed? :-(.
> @@ -737,6 +779,15 @@ static void wl1251_op_configure_filter(struct ieee80211_hw *hw,
> if (ret < 0)
> goto out;
>
> + if (*total & FIF_ALLMULTI || *total & FIF_PROMISC_IN_BSS)
> + ret = wl1251_acx_group_address_tbl(wl, false, NULL, 0);
> + else if (fp)
> + ret = wl1251_acx_group_address_tbl(wl, fp->enabled,
> + fp->mc_list,
> + fp->mc_list_length);
Is it correct not to call anything in !fp case (for example because we
were out of memory?)
> + if (ret < 0)
> + goto out;
> +
> /* send filters to firmware */
> wl1251_acx_rx_config(wl, wl->rx_config, wl->rx_filter);
>
> @@ -744,6 +795,7 @@ static void wl1251_op_configure_filter(struct ieee80211_hw *hw,
>
> out:
> mutex_unlock(&wl->mutex);
> + kfree(fp);
> }
Umm, this is interesting. Who frees the memory in the success case?
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 07/16] wl1251: configure hardware en-/decryption for monitor mode
From: Pavel Machek @ 2013-10-30 11:35 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-8-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:06, Pali Rohár wrote:
> From: David Gnedt <david.gnedt@davizone.at>
>
> Disable hardware encryption (DF_ENCRYPTION_DISABLE) and decryption
> (DF_SNIFF_MODE_ENABLE) via wl1251_acx_feature_cfg while monitor interface is
> present.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
You need to sign off the patch, otherwise looks ok.
Reviewed-by: Pavel Machek <pavel@ucw.cz>
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH 06/16] wl1251: split RX and TX data path initialisation
From: Pavel Machek @ 2013-10-30 11:31 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-7-git-send-email-pali.rohar@gmail.com>
Hi!
> Split up data path initialisation into RX and TX data path initialisation
> functions. This change is required for channel switching in monitor mode.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
> ---
> drivers/net/wireless/ti/wl1251/cmd.c | 37 ++++++++++++++++++++++++++-------
> drivers/net/wireless/ti/wl1251/cmd.h | 3 ++-
> drivers/net/wireless/ti/wl1251/init.c | 9 ++++++--
> 3 files changed, 39 insertions(+), 10 deletions(-)
>
> @@ -238,6 +235,32 @@ int wl1251_cmd_data_path(struct wl1251 *wl, u8 channel, bool enable)
> wl1251_debug(DEBUG_BOOT, "rx %s cmd channel %d",
> enable ? "start" : "stop", channel);
>
> +out:
> + kfree(cmd);
> + return ret;
> +}
> +
> +int wl1251_cmd_data_path_tx(struct wl1251 *wl, u8 channel, bool enable)
> +{
> + struct cmd_enabledisable_path *cmd;
> + int ret;
> + u16 cmd_tx;
> +
> + wl1251_debug(DEBUG_CMD, "cmd data path");
> +
> + cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
> + if (!cmd) {
> + ret = -ENOMEM;
> + goto out;
> + }
Again, doing jump just to kfree(NULL)... is probably not worth
it.
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH net-next 0/5] SCTP fix/updates
From: Neil Horman @ 2013-10-30 11:29 UTC (permalink / raw)
To: Daniel Borkmann; +Cc: davem, netdev, linux-sctp
In-Reply-To: <1383130252-1515-1-git-send-email-dborkman@redhat.com>
On Wed, Oct 30, 2013 at 11:50:47AM +0100, Daniel Borkmann wrote:
> Please see patch 5 for the main description/motivation, the rest just
> brings in the needed functionality for that. Although this is actually
> a fix, I've based it against net-next as some additional work for
> fixing it was needed.
>
> Thanks!
>
> Daniel Borkmann (5):
> lib: crc32: clean up spacing in test cases
> lib: crc32: add functionality to combine two crc32{,c}s in GF(2)
> lib: crc32: add test cases for crc32{,c}_combine routines
> net: skb_checksum: allow custom update/combine for walking skb
> net: sctp: fix and consolidate SCTP checksumming code
>
> include/linux/crc32.h | 40 ++++
> include/linux/skbuff.h | 13 +-
> include/net/checksum.h | 6 +
> include/net/sctp/checksum.h | 56 ++----
> lib/crc32.c | 453 +++++++++++++++++++++++++-------------------
> net/core/skbuff.c | 31 ++-
> net/sctp/output.c | 9 +-
> 7 files changed, 350 insertions(+), 258 deletions(-)
>
> --
> 1.8.3.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-sctp" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
^ permalink raw reply
* Re: [PATCH 05/16] wl1251: implement hardware ARP filtering
From: Pavel Machek @ 2013-10-30 11:28 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-6-git-send-email-pali.rohar@gmail.com>
Hi!
> Update hardware ARP filter configuration on BSS_CHANGED_ARP_FILTER
> notification from mac80211.
> Ported from wl1271 driver.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
> ---
> drivers/net/wireless/ti/wl1251/acx.c | 31 +++++++++++++++++++++++++++++++
> drivers/net/wireless/ti/wl1251/acx.h | 15 +++++++++++++++
> drivers/net/wireless/ti/wl1251/main.c | 13 +++++++++++++
> 3 files changed, 59 insertions(+)
>
> diff --git a/drivers/net/wireless/ti/wl1251/acx.c b/drivers/net/wireless/ti/wl1251/acx.c
> index cce50e2..9295090 100644
> --- a/drivers/net/wireless/ti/wl1251/acx.c
> +++ b/drivers/net/wireless/ti/wl1251/acx.c
> @@ -1062,6 +1062,37 @@ out:
> return ret;
> }
>
> +int wl1251_acx_arp_ip_filter(struct wl1251 *wl, bool enable, __be32 address)
> +{
> + struct wl1251_acx_arp_filter *acx;
> + int ret;
> +
> + wl1251_debug(DEBUG_ACX, "acx arp ip filter, enable: %d", enable);
> +
> + acx = kzalloc(sizeof(*acx), GFP_KERNEL);
> + if (!acx) {
> + ret = -ENOMEM;
> + goto out;
> + }
I'd do "return -ENOMEM;" here. Trying to free NULL pointer is
unneccessary complication.
> + acx->version = ACX_IPV4_VERSION;
> + acx->enable = enable;
> +
> + if (enable == true)
if (enable) would be C way of writing stuff.
> + memcpy(acx->address, &address, ACX_IPV4_ADDR_SIZE);
> +
> + ret = wl1251_cmd_configure(wl, ACX_ARP_IP_FILTER,
> + acx, sizeof(*acx));
> + if (ret < 0) {
> + wl1251_warning("failed to set arp ip filter: %d", ret);
> + goto out;
> + }
> +
> +out:
No need for the out label now.
> diff --git a/drivers/net/wireless/ti/wl1251/main.c b/drivers/net/wireless/ti/wl1251/main.c
> index 46a2494..9752745 100644
> --- a/drivers/net/wireless/ti/wl1251/main.c
> +++ b/drivers/net/wireless/ti/wl1251/main.c
> @@ -1078,6 +1078,19 @@ static void wl1251_op_bss_info_changed(struct ieee80211_hw *hw,
> }
> }
>
> + if (changed & BSS_CHANGED_ARP_FILTER) {
> + __be32 addr = bss_conf->arp_addr_list[0];
> + WARN_ON(wl->bss_type != BSS_TYPE_STA_BSS);
> +
> + if (bss_conf->arp_addr_cnt == 1 && bss_conf->assoc)
> + ret = wl1251_acx_arp_ip_filter(wl, true, addr);
> + else
> + ret = wl1251_acx_arp_ip_filter(wl, false, addr);
enable = bss_conf->arp_addr_cnt == 1 && bss_conf->assoc;
ret = wl1251_acx_arp_ip_filter(wl, enable, addr);
?
Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* [PATCH ] net_sched: actions - Add default lookup
From: Jamal Hadi Salim @ 2013-10-30 11:25 UTC (permalink / raw)
To: David Miller; +Cc: netdev@vger.kernel.org, Eric W. Biederman, Alexander Duyck
[-- Attachment #1: Type: text/plain, Size: 53 bytes --]
Attached. Tested with simple action.
cheers,
jamal
[-- Attachment #2: p1 --]
[-- Type: text/plain, Size: 613 bytes --]
commit 80f80120ba4b85daf00c53eceebe7f0ad0b58a57
Author: Jamal Hadi Salim <jhs@mojatatu.com>
Date: Wed Oct 30 07:03:55 2013 -0400
Provide default lookup function for actions that dont provide one
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
diff --git a/net/sched/act_api.c b/net/sched/act_api.c
index fd70728..3c974a0 100644
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -279,6 +279,10 @@ int tcf_register_action(struct tc_action_ops *act)
}
act->next = NULL;
*ap = act;
+
+ if (!act->lookup)
+ act->lookup = tcf_hash_search;
+
write_unlock(&act_mod_lock);
return 0;
}
^ permalink raw reply related
* Re: [PATCH 02/16] wl1251: fix scan behaviour while not associated
From: Pavel Machek @ 2013-10-30 11:24 UTC (permalink / raw)
To: Pali Rohár
Cc: Luciano Coelho, John W. Linville, Johannes Berg, David S. Miller,
linux-wireless, netdev, linux-kernel, freemangordon,
aaro.koskinen, sre, joni.lapilainen, David Gnedt
In-Reply-To: <1382819655-30430-3-git-send-email-pali.rohar@gmail.com>
On Sat 2013-10-26 22:34:01, Pali Rohár wrote:
> From: David Gnedt <david.gnedt@davizone.at>
>
> With a dissacociated card I often encoutered very long scan delays.
>
> My guess is that it has something to do with the cards DTIM handling and
> another firmware bug mentioned in the TI WLAN driver, which is described as
> the card may never end scanning if the channel is overloaded because it
> can't send probe requests. I think the firmware somehow also tries to
> receive DTIM messages when the BSSID is not set. Therefore most of the time
> it waits for DTIM messages and can't do scanning work.
>
> Anyway we can workaround this misbehaviour by setting the HIGH_PRIORITY
> bit for scans in disassociated state.
>
> Signed-off-by: David Gnedt <david.gnedt@davizone.at>
I guess you should add your Signed-off-by: here (as you are sending
the patch forward).
Other than that:
Reviewed-by: Pavel Machek <pavel@ucw.cz>
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
^ permalink raw reply
* Re: [PATCH net-next RFC 3/5] xen-netback: Remove old TX grant copy definitons
From: Wei Liu @ 2013-10-30 11:13 UTC (permalink / raw)
To: Zoltan Kiss
Cc: ian.campbell, wei.liu2, xen-devel, netdev, linux-kernel,
jonathan.davies
In-Reply-To: <1383094220-14775-4-git-send-email-zoltan.kiss@citrix.com>
On Wed, Oct 30, 2013 at 12:50:18AM +0000, Zoltan Kiss wrote:
> These became obsolate with grant mapping.
>
I'm afraid not.
This TX coalescing mechanism is designed to handle the situation where
guest's MAX_SKB_FRAGS > host's MAX_SKB_FRAGS.
To a further extent, I think you might need to add mechanism for backend
to tell frontend how many frags it can handle, and frontend needs to do
necessary coalescing. Until then you can safely use this new mapping
scheme.
Wei.
^ permalink raw reply
* Re: [PATCH net-next RFC 4/5] xen-netback: Fix indentations
From: Wei Liu @ 2013-10-30 11:13 UTC (permalink / raw)
To: Zoltan Kiss
Cc: ian.campbell, wei.liu2, xen-devel, netdev, linux-kernel,
jonathan.davies
In-Reply-To: <1383094220-14775-5-git-send-email-zoltan.kiss@citrix.com>
On Wed, Oct 30, 2013 at 12:50:19AM +0000, Zoltan Kiss wrote:
> I've left intentionally these indentations in this way, to improve readability of previous patches.
>
Apparently this doesn't deserve a single patch -- please squash it when
you post non-RFC series.
Wei.
^ permalink raw reply
* Re: [PATCH] x86: Run checksumming in parallel accross multiple alu's
From: Neil Horman @ 2013-10-30 11:02 UTC (permalink / raw)
To: Doug Ledford; +Cc: Ingo Molnar, Eric Dumazet, linux-kernel, netdev
In-Reply-To: <201310300525.r9U5Pdqo014902@ib.usersys.redhat.com>
On Wed, Oct 30, 2013 at 01:25:39AM -0400, Doug Ledford wrote:
> * Neil Horman <nhorman@tuxdriver.com> wrote:
> > 3) The run times are proportionally larger, but still indicate that Parallel ALU
> > execution is hurting rather than helping, which is counter-intuitive. I'm
> > looking into it, but thought you might want to see these results in case
> > something jumped out at you
>
> So here's my theory about all of this.
>
> I think that the original observation some years back was a fluke caused by
> either a buggy CPU or a CPU design that is no longer used.
>
> The parallel ALU design of this patch seems OK at first glance, but it means
> that two parallel operations are both trying to set/clear both the overflow
> and carry flags of the EFLAGS register of the *CPU* (not the ALU). So, either
> some CPU in the past had a set of overflow/carry flags per ALU and did some
> sort of magic to make sure that the last state of those flags across multiple
> ALUs that might have been used in parallelizing work were always in the CPU's
> logical EFLAGS register, or the CPU has a buggy microcode that allowed two
> ALUs to operate on data at the same time in situations where they would
> potentially stomp on the carry/overflow flags of the other ALUs operations.
>
> It's my theory that all modern CPUs have this behavior fixed, probably via a
> microcode update, and so trying to do parallel ALU operations like this simply
> has no effect because the CPU (rightly so) serializes the operations to keep
> them from clobbering the overflow/carry flags of the other ALUs operations.
>
> My additional theory then is that the reason you see a slowdown from this
> patch is because the attempt to parallelize the ALU operation has caused
> us to write a series of instructions that, once serialized, are non-optimal
> and hinder smooth pipelining of the data (aka going 0*8, 2*8, 4*8, 6*8, 1*8,
> 3*8, 5*8, and 7*8 in terms of memory accesses is worse than doing them in
> order, and since we aren't getting the parallel operation we want, this
> is the net result of the patch).
>
> It would explain things anyway.
>
That does makes sense, but it then begs the question, whats the advantage of
having multiple alu's at all? If they're just going to serialize on the
updating of the condition register, there doesn't seem to be much advantage in
having multiple alu's at all, especially if a common use case (parallelizing an
operation on a large linear dataset) resulted in lower performance.
/me wonders if rearranging the instructions into this order:
adcq 0*8(src), res1
adcq 1*8(src), res2
adcq 2*8(src), res1
would prevent pipeline stalls. That would be interesting data, and (I think)
support your theory, Doug. I'll give that a try
Neil
^ permalink raw reply
* Re: [PATCH 00/19] Enable various Renesas drivers on all ARM platforms
From: Tomi Valkeinen @ 2013-10-30 10:59 UTC (permalink / raw)
To: Simon Horman, Mark Brown, Laurent Pinchart
Cc: linux-fbdev, Wolfram Sang, Linus Walleij, Guennadi Liakhovetski,
Thierry Reding, linux-mtd, linux-i2c, Laurent Pinchart,
Vinod Koul, Joerg Roedel, linux-sh, Magnus Damm, Eduardo Valentin,
linux-serial, linux-input, Zhang Rui, Chris Ball,
Jean-Christophe Plagniol-Villard, linux-media, linux-pwm,
Samuel Ortiz, linux-pm, Ian Molton, linux-arm-kernel, Sergei
In-Reply-To: <20131030000501.GE21262@verge.net.au>
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On 2013-10-30 02:05, Simon Horman wrote:
> On Tue, Oct 29, 2013 at 10:58:34AM -0700, Mark Brown wrote:
>> On Tue, Oct 29, 2013 at 06:29:59PM +0100, Laurent Pinchart wrote:
>>> On Tuesday 29 October 2013 10:23:31 Mark Brown wrote:
>>>> On Tue, Oct 29, 2013 at 06:05:53PM +0100, Laurent Pinchart wrote:
>>>>> The first one is that I can't compile-test all those drivers on all
>>>>> architectures. The spi-sh-msiof driver, for instance, uses
>>>>> io(read|write)(16|
>>
>>>> Which architectures are these and is there not a symbol we can depend on
>>>> for them?
>>
>>> arch/cris for instance. We can use readl/writel instead (maybe it would be
>>> time to rationalize and document the I/O accessors across all architectures,
>>> but that's another topic).
>>
>> It'd certainly be sensible, or adding a config option to depend on if
>> you rely on these functions.
>>
>>> My point is that there might be other issues that I won't be able to easily
>>> catch. This would break compilation for everybody for no reason, as the
>>> drivers are useless on non-SuperH, non-ARM platforms. That's why I believe
>>> COMPILE_TEST would be a better option as a first step.
>>
>> Yes, it would - please do that. Note that it won't stop anyone running
>> into build issues on other architectures though, it's just about
>> stopping Kconfig noise.
>
> FWIW, I am happy with using COMPILE_TEST for this series.
I'd also go for COMPILE_TEST. I once enabled omapdss and omapfb to be
compilable without any extra dependencies, and Linus wasn't fond of
getting asked if he wants to compile omapfb or not...
Tomi
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^ permalink raw reply
* [PATCH net-next 5/5] net: sctp: fix and consolidate SCTP checksumming code
From: Daniel Borkmann @ 2013-10-30 10:50 UTC (permalink / raw)
To: davem; +Cc: netdev, linux-sctp
In-Reply-To: <1383130252-1515-1-git-send-email-dborkman@redhat.com>
This fixes an outstanding bug found through IPVS, where SCTP packets
with skb->data_len > 0 (non-linearized) and empty frag_list, but data
accumulated in frags[] member, are forwarded with incorrect checksum
letting SCTP initial handshake fail on some systems. Linearizing each
SCTP skb in IPVS to prevent that would not be a good solution as
this leads to an additional and unnecessary performance penalty on
the load-balancer itself for no good reason (as we actually only want
to update the checksum, and can do that in a different/better way
presented here).
The actual problem is elsewhere, namely, that SCTP's checksumming
in sctp_compute_cksum() does not take frags[] into account like
skb_checksum() does. So while we are fixing this up, we better reuse
the existing code that we have anyway in __skb_checksum() and use it
for walking through the data doing checksumming. This will not only
fix this issue, but also consolidates some SCTP code with core
sk_buff code, bringing it closer together and removing respectively
avoiding reimplementation of skb_checksum() for no good reason.
As crc32c() can use hardware implementation within the crypto layer,
we leave that intact (it wraps around / falls back to e.g. slice-by-8
algorithm in __crc32c_le() otherwise); plus use the __crc32c_le_combine()
combinator for crc32c blocks.
Also, we remove all other SCTP checksumming code, so that we only
have to use sctp_compute_cksum() from now on; for doing that, we need
to transform SCTP checkumming in output path slightly, and can leave
the rest intact.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
---
include/net/sctp/checksum.h | 56 +++++++++++++++------------------------------
net/sctp/output.c | 9 +-------
2 files changed, 20 insertions(+), 45 deletions(-)
diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
index 259924d..6bd44fe 100644
--- a/include/net/sctp/checksum.h
+++ b/include/net/sctp/checksum.h
@@ -42,56 +42,38 @@
#include <linux/types.h>
#include <net/sctp/sctp.h>
#include <linux/crc32c.h>
+#include <linux/crc32.h>
-static inline __u32 sctp_crc32c(__u32 crc, u8 *buffer, u16 length)
+static inline __wsum sctp_csum_update(const void *buff, int len, __wsum sum)
{
- return crc32c(crc, buffer, length);
-}
-
-static inline __u32 sctp_start_cksum(__u8 *buffer, __u16 length)
-{
- __u32 crc = ~(__u32)0;
- __u8 zero[sizeof(__u32)] = {0};
-
- /* Optimize this routine to be SCTP specific, knowing how
- * to skip the checksum field of the SCTP header.
+ /* This uses the crypto implementation of crc32c, which is either
+ * implemented w/ hardware support or resolves to __crc32c_le().
*/
-
- /* Calculate CRC up to the checksum. */
- crc = sctp_crc32c(crc, buffer, sizeof(struct sctphdr) - sizeof(__u32));
-
- /* Skip checksum field of the header. */
- crc = sctp_crc32c(crc, zero, sizeof(__u32));
-
- /* Calculate the rest of the CRC. */
- crc = sctp_crc32c(crc, &buffer[sizeof(struct sctphdr)],
- length - sizeof(struct sctphdr));
- return crc;
-}
-
-static inline __u32 sctp_update_cksum(__u8 *buffer, __u16 length, __u32 crc32)
-{
- return sctp_crc32c(crc32, buffer, length);
+ return crc32c(sum, buff, len);
}
-static inline __le32 sctp_end_cksum(__u32 crc32)
+static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
+ int offset, int len)
{
- return cpu_to_le32(~crc32);
+ return __crc32c_le_combine(csum, csum2, len);
}
-/* Calculate the CRC32C checksum of an SCTP packet. */
static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
unsigned int offset)
{
- const struct sk_buff *iter;
+ struct sctphdr *sh = sctp_hdr(skb);
+ __le32 ret, old = sh->checksum;
+ const struct skb_checksum_ops ops = {
+ .update = sctp_csum_update,
+ .combine = sctp_csum_combine,
+ };
- __u32 crc32 = sctp_start_cksum(skb->data + offset,
- skb_headlen(skb) - offset);
- skb_walk_frags(skb, iter)
- crc32 = sctp_update_cksum((__u8 *) iter->data,
- skb_headlen(iter), crc32);
+ sh->checksum = 0;
+ ret = cpu_to_le32(~__skb_checksum(skb, offset, skb->len - offset,
+ ~(__u32)0, &ops));
+ sh->checksum = old;
- return sctp_end_cksum(crc32);
+ return ret;
}
#endif /* __sctp_checksum_h__ */
diff --git a/net/sctp/output.c b/net/sctp/output.c
index 3191373..e650978 100644
--- a/net/sctp/output.c
+++ b/net/sctp/output.c
@@ -390,7 +390,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
__u8 has_data = 0;
struct dst_entry *dst = tp->dst;
unsigned char *auth = NULL; /* pointer to auth in skb data */
- __u32 cksum_buf_len = sizeof(struct sctphdr);
pr_debug("%s: packet:%p\n", __func__, packet);
@@ -493,7 +492,6 @@ int sctp_packet_transmit(struct sctp_packet *packet)
if (chunk == packet->auth)
auth = skb_tail_pointer(nskb);
- cksum_buf_len += chunk->skb->len;
memcpy(skb_put(nskb, chunk->skb->len),
chunk->skb->data, chunk->skb->len);
@@ -538,12 +536,7 @@ int sctp_packet_transmit(struct sctp_packet *packet)
if (!sctp_checksum_disable) {
if (!(dst->dev->features & NETIF_F_SCTP_CSUM) ||
(dst_xfrm(dst) != NULL) || packet->ipfragok) {
- __u32 crc32 = sctp_start_cksum((__u8 *)sh, cksum_buf_len);
-
- /* 3) Put the resultant value into the checksum field in the
- * common header, and leave the rest of the bits unchanged.
- */
- sh->checksum = sctp_end_cksum(crc32);
+ sh->checksum = sctp_compute_cksum(nskb, 0);
} else {
/* no need to seed pseudo checksum for SCTP */
nskb->ip_summed = CHECKSUM_PARTIAL;
--
1.8.3.1
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