workqueues - how to use them correctly

Arun KS getarunks at
Wed Feb 11 06:28:27 EST 2015

Hello Roshan,

On Tue, Feb 10, 2015 at 2:20 PM, Roshan A <roshan.len at> wrote:
> hi all,
> My question is regarding the correct use of workqueues. I have a
> driver which queues a work item in the interrupt handler. The bottom
> half function ( the workitem -function ) does have proper locking (
> mutex ) in place for atomicity.
> With this setup, since the interrupts are enabled, it's possible to
> have a scenario where, when one workitem is being executed, another
> can be queued up, which results in the workitems being executed in
> parallel, however since there is a mutex, one thread will sleep.
> is this particular scenario considered bad or discouraged ?

This should not happen if you are using the same work item.
All workqueues are now non-reentrant - any work item is guaranteed to
be executed by at most one worker system-wide at any given time.

> Thank you,
> -Roshan
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