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| /openbmc/linux/drivers/block/drbd/ |
| H A D | drbd_actlog.c | diff 7dc1d67f7c324e5bf23883b94508112ca7a70f62 Tue May 03 09:49:20 CDT 2011 Lars Ellenberg <lars.ellenberg@linbit.com> drbd: skip spurious wait_event in drbd_al_begin_io
Activity log transaction writes are serialized on a bit lock.
If several CPUs race to write an AL transaction,
those that did not get the lock the first time
may continue as soon as there are no more pending transactions.
The do not need to all grab the lock in turn,
just to realize that the AL is clean already,
and they have nothing to do.
This also closes a potential deadlock with drbd_adm_disk_opts.
Once it got the AL bit lock, it knows there are no pending transactions,
the AL is clean, and it should be safe to wait for all element references
to drop to zero.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
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