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While documentation suggests atomic_inc_not_zero_hint() will perform better
than atomic_inc_not_zero(), this is unlikely to be the case. No architectures
implement atomic_inc_not_zero_hint() directly, and thus it either falls back to
atomic_inc_not_zero(), or a loop using atomic_cmpxchg().
Whenever the hint does not match the value in memory, the repeated use of
atomic_cmpxchg() will be more expensive than the read that
atomic_inc_not_zero_hint() attempts to avoid. For architectures with LL/SC
atomics, a read cannot be avoided, and it would always be better to use
atomic_inc_not_zero() directly. For other architectures, their own
atomic_inc_not_zero() is likely to be more optimal than an atomic_cmpxchg()
loop regardless.
Generally, atomic_inc_not_zero_hint() is liable to perform worse than
atomic_inc_not_zero(). Further, atomic_inc_not_zero_hint() only exists
for atomic_t, and not atomic64_t or atomic_long_t, and there is only one
user in the kernel tree.
Given all this, let's remove atomic_inc_not_zero_hint(), and migrate the
existing user over to atomic_inc_not_zero().
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-4-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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ATM accounts for in-flight TX packets in sk_wmem_alloc of the VCC on
which they are to be sent. But it doesn't take ownership of those
packets from the sock (if any) which originally owned them. They should
remain owned by their actual sender until they've left the box.
There's a hack in pskb_expand_head() to avoid adjusting skb->truesize
for certain skbs, precisely to avoid messing up sk_wmem_alloc
accounting. Ideally that hack would cover the ATM use case too, but it
doesn't — skbs which aren't owned by any sock, for example PPP control
frames, still get their truesize adjusted when the low-level ATM driver
adds headroom.
This has always been an issue, it seems. The truesize of a packet
increases, and sk_wmem_alloc on the VCC goes negative. But this wasn't
for normal traffic, only for control frames. So I think we just got away
with it, and we probably needed to send 2GiB of LCP echo frames before
the misaccounting would ever have caused a problem and caused
atm_may_send() to start refusing packets.
Commit 14afee4b609 ("net: convert sock.sk_wmem_alloc from atomic_t to
refcount_t") did exactly what it was intended to do, and turned this
mostly-theoretical problem into a real one, causing PPPoATM to fail
immediately as sk_wmem_alloc underflows and atm_may_send() *immediately*
starts refusing to allow new packets.
The least intrusive solution to this problem is to stash the value of
skb->truesize that was accounted to the VCC, in a new member of the
ATM_SKB(skb) structure. Then in atm_pop_raw() subtract precisely that
value instead of the then-current value of skb->truesize.
Fixes: 158f323b9868 ("net: adjust skb->truesize in pskb_expand_head()")
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Tested-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
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refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Mostly scripted conversion of the smp_mb__* barriers.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/n/tip-55dhyhocezdw1dg7u19hmh1u@git.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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We don't need to schedule the wakeup tasklet on *every* unlock; only if we
actually blocked the channel in the first place.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Krzysztof Mazur <krzysiek@podlesie.net>
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Now that we can return zero from pppoatm_send() for reasons *other* than
the queue being full, that means we can't depend on a subsequent call to
pppoatm_pop() waking the queue, and we might leave it stalled
indefinitely.
Use the ->release_cb() callback to wake the queue after the sock is
unlocked.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Acked-by: Krzysztof Mazur <krzysiek@podlesie.net>
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The pppoatm_may_send() is quite heavy and it's called three times
in pppoatm_send() and inlining costs more than 200 bytes of code
(more than 10% of total pppoatm driver code size).
add/remove: 1/0 grow/shrink: 0/1 up/down: 132/-367 (-235)
function old new delta
pppoatm_may_send - 132 +132
pppoatm_send 900 533 -367
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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The vcc_destroy_socket() closes vcc before the protocol is detached
from vcc by calling vcc->push() with NULL skb. This leaves some time
window, where the protocol may call vcc->send() on closed vcc
and crash.
Now pppoatm_send(), like vcc_sendmsg(), checks for vcc flags that
indicate that vcc is not ready. If the vcc is not ready we just
drop frame. Queueing frames is much more complicated because we
don't have callbacks that inform us about vcc flags changes.
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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The pppoatm_send() does not take any lock that will prevent concurrent
vcc_sendmsg(). This causes two problems:
- there is no locking between checking the send queue size
with atm_may_send() and incrementing sk_wmem_alloc,
and the real queue size can be a little higher than sk_sndbuf
- the vcc->sendmsg() can be called concurrently. I'm not sure
if it's allowed. Some drivers (eni, nicstar, ...) seem
to assume it will never happen.
Now pppoatm_send() takes ATM socket lock, the same that is used
in vcc_sendmsg() and other ATM socket functions. The pppoatm_send()
is called with BH disabled, so bh_lock_sock() is used instead
of lock_sock().
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Cc: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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The pppoatm used module_put() during unassignment from vcc with
hope that we have BKL. This assumption is no longer true.
Now owner field in atmvcc is used to move this module_put()
to vcc_destroy_socket().
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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The pppoatm does not check if used vcc is in connected state,
causing an Oops in pppoatm_send() when vcc->send() is called
on not fully connected socket.
Now pppoatm can be assigned only on connected sockets; otherwise
-EINVAL error is returned.
Signed-off-by: Krzysztof Mazur <krzysiek@podlesie.net>
Cc: Chas Williams - CONTRACTOR <chas@cmf.nrl.navy.mil>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
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Remove some dropwatch/drop_monitor false positives.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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We discovered that PPPoATM has an excessively deep transmit queue. A
queue the size of the default socket send buffer (wmem_default) is
maintained between the PPP generic core and the ATM device.
Fix it to queue a maximum of *two* packets. The one the ATM device is
currently working on, and one more for the ATM driver to process
immediately in its TX done interrupt handler. The PPP core is designed
to feed packets to the channel with minimal latency, so that really
ought to be enough to keep the ATM device busy.
While we're at it, fix the fact that we were triggering the wakeup
tasklet on *every* pppoatm_pop() call. The comment saying "this is
inefficient, but doing it right is too hard" turns out to be overly
pessimistic... I think :)
On machines like the Traverse Geos, with a slow Geode CPU and two
high-speed ADSL2+ interfaces, there were reports of extremely high CPU
usage which could partly be attributed to the extra wakeups.
(The wakeup handling could actually be made a whole lot easier if we
stop checking sk->sk_sndbuf altogether. Given that we now only queue
*two* packets ever, one wonders what the point is. As it is, you could
already deadlock the thing by setting the sk_sndbuf to a value lower
than the MTU of the device, and it'd just block for ever.)
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Since all that include/linux/if_ppp.h does is #include <linux/ppp-ioctl.h>,
this replaces the occurrences of #include <linux/if_ppp.h> with
#include <linux/ppp-ioctl.h>.
It also corrects an error in Documentation/networking/l2tp.txt, where
it referenced include/linux/if_ppp.h as the source of some definitions
that are actually now defined in include/linux/if_pppol2tp.h.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This function moves the implementation found in the clip and br2684
modules to common code, correctly unlinks the skb from the queue
before pushing it and makes pppoatm use it.
Signed-off-by: Jorge Boncompte [DTI2] <jorge@dti2.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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* remove interrupt.g inclusion from netdevice.h -- not needed
* fixup fallout, add interrupt.h and hardirq.h back where needed.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The PPP channel ops structure should be const.
Cleanup the declarations to use standard C99 format.
Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
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Move embedded assigns out of tests
Move trailing statements to new lines
Move labels to column 1
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Add #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
Remove function names from output
Use single line pr_debug instead of broken multiple uses without newline
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Get rid of using DPRINTK macro in ATM and use pr_debug (in kernel.h).
Using the standard macro is cleaner and forces code to check for bad arguments
and formatting.
Fixes from Thomas Graf.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Panagiotis Issaris <takis@issaris.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
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net: Use <linux/capability.h> where capable() is used.
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
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