tree d94a35abcd3b227b072955622f703a2cdc3c309d
parent c4ec7908c2c5125f75fabd100e7a95626a6883ee
author Artem Bityutskiy <Artem.Bityutskiy@nokia.com> 1280057355 +0300
committer Jens Axboe <jaxboe@fusionio.com> 1281200035 +0200

writeback: do not lose wake-ups in bdi threads

Currently, bdi threads ('bdi_writeback_thread()') can lose wake-ups. For
example, if 'bdi_queue_work()' is executed after the bdi thread have had
finished 'wb_do_writeback()' but before it called
'schedule_timeout_interruptible()'.

To fix this issue, we have to check whether we have works to process after we
have changed the task state to 'TASK_INTERRUPTIBLE'.

This patch also clean-ups handling of the cases when 'dirty_writeback_interval'
is zero or non-zero.

Additionally, this patch also removes unneeded 'list_empty_careful()' call.

Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>