In order to align the coding styles of ip_vs_zero_stats() and
its child-function ip_vs_zero_estimator(), clear ip_vs_stats
members explicitlty rather than doing a limited memset().

This was chosen over modifying ip_vs_zero_estimator() to use
memset() as it is more robust against changes in members
in the relevant structures. memset() would be prefered if
all members of the structure were to be cleared.

Cc: Sven Wegener <sven.wegener@stealer.net>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>

It's a global variable and automatically initialized to zero. And now we can
also initialize the lock at compile time.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

There's no reason for dynamically allocating an estimator object for every
stats object. Directly embed an estimator object into every stats object and
switch to using the kernel-provided list implementation. This makes the code
much simpler and faster, as we do not need to traverse the list of all
estimators to find the one belonging to a stats object. There's no need to use
an rwlock, as we only have one reader. Also reorder the members of the
estimator structure slightly to avoid padding overhead. This can't be done
with the stats object as the members are currently copied to our user space
object via memcpy() and changing it would break ABI.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

Being able to discard these functions saves a couple of bytes at runtime. The
cleanup functions can't be annotated with __exit as they are also called from
init functions.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

No need to do it at runtime and this saves a couple of bytes in the text
section.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

There is a slight chance for a deadlock in the estimator code. We can't call
del_timer_sync() while holding our lock, as the timer might be active and
spinning for the lock on another cpu. Work around this issue by using
try_to_del_timer_sync() and releasing the lock. We could actually delete the
timer outside of our lock, as the add and kill functions are only every called
from userspace via [gs]etsockopt() and are serialized by a mutex, but better
make this explicit.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Cc: stable <stable@kernel.org>
Acked-by: Simon Horman <horms@verge.net.au>

Commit 998e7a76804b7a273a0460c2cdd5a51fa9856717 ("ipvs: Use kthread_run()
instead of doing a double-fork via kernel_thread()") introduced a possible
deadlock in the sync code. We need to use the _bh versions for the lock, as the
lock is also accessed from a bottom half.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>