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NeilBrown authored
This patch converts bioset_create() to not create a workqueue by default, so alloctions will never trigger punt_bios_to_rescuer(). It also introduces a new flag BIOSET_NEED_RESCUER which tells bioset_create() to preserve the old behavior. All callers of bioset_create() that are inside block device drivers, are given the BIOSET_NEED_RESCUER flag. biosets used by filesystems or other top-level users do not need rescuing as the bio can never be queued behind other bios. This includes fs_bio_set, blkdev_dio_pool, btrfs_bioset, xfs_ioend_bioset, and one allocated by target_core_iblock.c. biosets used by md/raid do not need rescuing as their usage was recently audited and revised to never risk deadlock. It is hoped that most, if not all, of the remaining biosets can end up being the non-rescued version. Reviewed-by:
Christoph Hellwig <hch@lst.de> Credit-to: Ming Lei <ming.lei@redhat.com> (minor fixes) Reviewed-by:
Ming Lei <ming.lei@redhat.com> Signed-off-by:
NeilBrown <neilb@suse.com> Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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