Messages in this thread | | | Date | Wed, 25 Jul 2007 22:20:19 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 1/4] drivers edac fix reset edac_mc pollmsec |
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On Wed, 25 Jul 2007 14:54:21 -0600 dougthompson@xmission.com wrote:
> +void edac_mc_reset_delay_period(int value) > { > - /* cancel the current workq request */ > - edac_mc_workq_teardown(mci); > + struct mem_ctl_info *mci; > + struct list_head *item; > + > + mutex_lock(&mem_ctls_mutex); > + > + /* scan the list and turn off all workq timers, doing so under lock > + */ > + list_for_each(item, &mc_devices) { > + mci = list_entry(item, struct mem_ctl_info, link); > + > + if (mci->op_state == OP_RUNNING_POLL) > + cancel_delayed_work(&mci->work); > + } > + > + mutex_unlock(&mem_ctls_mutex);
cancel_delayed_work() on its own looks a bit racy. The work could presently be running on another CPU.
So generally we'll run flush_workqueue() or cancel_work_sync() after the cancel_delayed_work() to make sure that it has really gone away.
Beware however that you're holding a lock here. If any of the work functions which can be at mci->work also take mem_ctls_mutex then it is deadlocky to run flush_workqueue() or cancel_work_sync() while holding that lock.
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