Messages in this thread | | | From | Tejun Heo <> | Subject | [PATCHSET wq/for-3.15] workqueue: remove PREPARE_[DELAYED_]WORK() | Date | Thu, 20 Feb 2014 15:44:22 -0500 |
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Peter Hurley noticed that since a2c1c57be8d9 ("workqueue: consider work function when searching for busy work items"), a work item which gets assigned a different work function would break out of the non-reentrancy guarantee as workqueue would consider it a different work item.
This is fragile and extremely subtle. PREPARE_[DELAYED_]WORK() have never been used widely and its semantics has always been somewhat iffy. If the work item is known not to be on queue when PREPARE_WORK() is called, there's no difference from using INIT_WORK(). If the work item may be queued at the time of PREPARE_WORK(), we can't really tell whether the old or new function will be executed the next time.
We really don't want this level of subtlety in workqueue interface for such marginal use cases. The previous patches converted all existing users away from PREPARE_[DELAYED_]WORK(). Let's remove them.
This patchset contains the following nine patches.
0001-wireless-rt2x00-don-t-use-PREPARE_WORK-in-rt2800usb..patch 0002-ps3-vuart-don-t-use-PREPARE_WORK.patch 0003-floppy-don-t-use-PREPARE_-DELAYED_-WORK.patch 0004-firewire-don-t-use-PREPARE_DELAYED_WORK.patch 0005-usb-don-t-use-PREPARE_DELAYED_WORK.patch 0006-nvme-don-t-use-PREPARE_WORK.patch 0007-afs-don-t-use-PREPARE_WORK.patch 0008-staging-fwserial-don-t-use-PREPARE_WORK.patch 0009-workqueue-remove-PREPARE_-DELAYED_-WORK.patch
0001-0008 convert existing users.
0009 removes them.
This patchset is on top of e95003c3f9ccb ("Merge tag 'nfs-for-3.14-4' of git://git.linux-nfs.org/projects/trondmy/linux-nfs") and also available in the following git branch.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git review-kill-PREPARE_WORK
diffstat follows.
drivers/block/floppy.c | 42 +++++++++++++++++++++----------- drivers/block/nvme-core.c | 18 +++++++++---- drivers/firewire/core-device.c | 22 +++++++++++----- drivers/firewire/sbp2.c | 17 +++++++++--- drivers/net/wireless/rt2x00/rt2800usb.c | 2 - drivers/ps3/ps3-vuart.c | 4 --- drivers/staging/fwserial/fwserial.c | 13 +++++++-- drivers/staging/fwserial/fwserial.h | 1 drivers/usb/core/hub.c | 13 +++++++-- drivers/usb/core/hub.h | 1 fs/afs/internal.h | 1 fs/afs/rxrpc.c | 12 +++++++-- include/linux/firewire.h | 1 include/linux/nvme.h | 1 include/linux/workqueue.h | 15 +---------- 15 files changed, 107 insertions(+), 56 deletions(-)
Thanks.
-- tejun
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