net: autoconvert trivial BKL users to private mutex

All these files use the big kernel lock in a trivial
way to serialize their private file operations,
typically resulting from an earlier semi-automatic
pushdown from VFS.

None of these drivers appears to want to lock against
other code, and they all use the BKL as the top-level
lock in their file operations, meaning that there
is no lock-order inversion problem.

Consequently, we can remove the BKL completely,
replacing it with a per-file mutex in every case.
Using a scripted approach means we can avoid
typos.

file=$1
name=$2
if grep -q lock_kernel ${file} ; then
    if grep -q 'include.*linux.mutex.h' ${file} ; then
            sed -i '/include.*<linux\/smp_lock.h>/d' ${file}
    else
            sed -i 's/include.*<linux\/smp_lock.h>.*$/include <linux\/mutex.h>/g' ${file}
    fi
    sed -i ${file} \
        -e "/^#include.*linux.mutex.h/,$ {
                1,/^\(static\|int\|long\)/ {
                     /^\(static\|int\|long\)/istatic DEFINE_MUTEX(${name}_mutex);

} }"  \
    -e "s/\(un\)*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \
    -e '/[      ]*cycle_kernel_lock();/d'
else
    sed -i -e '/include.*\<smp_lock.h\>/d' ${file}  \
                -e '/cycle_kernel_lock()/d'
fi

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
ppp: potential NULL dereference in ppp_mp_explode()

Smatch complains because we check whether "pch->chan" is NULL and then
dereference it unconditionally on the next line.  Partly the reason this
bug was introduced is because code was too complicated.  I've simplified
it a little.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ppp: Use a real SKB control block in fragmentation engine.

Do this instead of subverting fields in skb proper.

The macros that could very easily match variable or function
names were also just asking for trouble.

Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:

	drivers/net/ppp_generic.c
llseek: automatically add .llseek fop

cherry-picked for ppp_generic.c
filter: optimize sk_run_filter

Remove pc variable to avoid arithmetic to compute fentry at each filter
instruction. Jumps directly manipulate fentry pointer.

As the last instruction of filter[] is guaranteed to be a RETURN, and
all jumps are before the last instruction, we dont need to check filter
bounds (number of instructions in filter array) at each iteration, so we
remove it from sk_run_filter() params.

On x86_32 remove f_k var introduced in commit 57fe93b374a6b871
(filter: make sure filters dont read uninitialized memory)

Note : We could use a CONFIG_ARCH_HAS_{FEW|MANY}_REGISTERS in order to
avoid too many ifdefs in this code.

This helps compiler to use cpu registers to hold fentry and A
accumulator.

On x86_32, this saves 401 bytes, and more important, sk_run_filter()
runs much faster because less register pressure (One less conditional
branch per BPF instruction)

   text    data     bss     dec     hex filename
   2948       0       0    2948     b84 net/core/filter.o
   3349       0       0    3349     d15 net/core/filter_pre.o

on x86_64 :
   text    data     bss     dec     hex filename
   5173       0       0    5173    1435 net/core/filter.o
   5224       0       0    5224    1468 net/core/filter_pre.o

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:

	net/core/filter.c
	net/core/timestamping.c
net, ppp: Report correct error code if unit allocation failed

Allocating unit from ird might return several error codes
not only -EAGAIN, so it should not be changed and returned
precisely. Same time unit release procedure should be invoked
only if device is unregistering.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
ppp: allow disabling multilink protocol ID compression

Linux would not connect to other router running old version Cisco IOS (12.0).
This is most likely a bug in that version of IOS, since it is fixed
in later versions. As a workaround this patch allows a module parameter
to be set to disable compressing the protocol ID.

See: https://bugzilla.vyatta.com/show_bug.cgi?id=3979

RFC 1990 allows an implementation to formulate MP fragments as if protocol
compression had been negotiated.  This allows us to always send compressed
protocol IDs.  But some implementations don't accept MP fragments with
compressed protocol IDs.  This parameter allows us to interoperate with
them.  The default value of the configurable parameter is the same as the
current behavior:  protocol compression is enabled.  If protocol compression
is disabled we will not send compressed protocol IDs.

This is based on an earlier patch by Bob Gilligan (using a sysctl).
Module parameter is writable to allow for enabling even if ppp
is already loaded for other uses.

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
ppp: Clean up kernel log messages.

Use netdev_*() and pr_*().

To preserve existing semantics in cases where KERN_DEBUG is indeed
appropriate, use netdev_printk(KERN_DEBUG, ...)

Convert PPPIOCDETACH to pr_warn() because an unexpected file count is
a serious bug and should be logged with KERN_WARN.

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
ppp: Reconstruct fragmented packets using frag lists instead of copying.

[paulus@samba.org: fixed a couple of bugs]

Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
ppp: Use SKB queue abstraction interfaces in fragment processing.

No more direct references to SKB queue and list implementation
details.

Signed-off-by: David S. Miller <davem@davemloft.net>
net: ppp: Fix common misspellings in ppp_generic
net: Reorder incoming packets in PPPoLAC and PPPoPNS.

PPP handles packet loss but does not work with out of order packets.
This change performs reordering of incoming data packets within a
sliding window of one second. Since sequence number is optional,
receiving a packet without it will drop all queued packets.

Currently the logic is triggered by incoming packets, so queued
packets have to wait till another packet is arrived. It is done for
simplicity since no additional locks or threads are required. For
reliable protocols, a retransmission will kick it. For unreliable
protocols, queued packets just seem like packet loss. Time-critical
protocols might be broken, but they never work with queueing anyway.

Signed-off-by: Chia-chi Yeh <chiachi@android.com>
net: constify some ppp/pptp structs

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Conflicts:

	drivers/net/pptp.c