From: Jakub Kicinski <kuba@kernel.org>
To: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Cc: netdev@vger.kernel.org, Dany Madden <drt@linux.ibm.com>,
Lijun Pan <ljp@linux.ibm.com>
Subject: Re: [PATCH 5/7] ibmvnic: use a lock to serialize remove/reset
Date: Mon, 11 Jan 2021 11:43:09 -0800 [thread overview]
Message-ID: <20210111114309.6de6a281@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <20210111035225.GB165065@us.ibm.com>
On Sun, 10 Jan 2021 19:52:25 -0800 Sukadev Bhattiprolu wrote:
> Jakub Kicinski [kuba@kernel.org] wrote:
> > On Thu, 7 Jan 2021 23:12:34 -0800 Sukadev Bhattiprolu wrote:
> > > Use a separate lock to serialze ibmvnic_reset() and ibmvnic_remove()
> > > functions. ibmvnic_reset() schedules work for the worker thread and
> > > ibmvnic_remove() flushes the work before removing the adapter. We
> > > don't want any work to be scheduled once we start removing the
> > > adapter (i.e after we have already flushed the work).
> >
> > Locking based on functions, not on data being accessed is questionable
> > IMO. If you don't want work to be scheduled isn't it enough to have a
> > bit / flag that you set to let other flows know not to schedule reset?
>
> Maybe I could improve the description, but the "data" being protected
> is the work queue. Basically don't add to the work queue while/after
> it is (being) flushed.
>
> Existing code is checking for the VNIC_REMOVING state before scheduling
> the work but without a lock. If state goes to REMOVING after we check,
> we could schedule work after the flush?
I see, and you can't just use the state_lock because it has to be a
spin_lock? If that's the case please just update the commit message
and comments to describe the data protected.
next prev parent reply other threads:[~2021-01-11 19:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-08 7:12 [PATCH 0/7] ibmvnic: Use more consistent locking Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 1/7] ibmvnic: restore state in change-param reset Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 2/7] ibmvnic: update reset function prototypes Sukadev Bhattiprolu
2021-01-10 3:37 ` Jakub Kicinski
2021-01-11 3:12 ` Sukadev Bhattiprolu
2021-01-11 19:32 ` Jakub Kicinski
2021-01-11 19:57 ` Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 3/7] ibmvnic: avoid allocating rwi entries Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 4/7] ibmvnic: switch order of checks in ibmvnic_reset Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 5/7] ibmvnic: use a lock to serialize remove/reset Sukadev Bhattiprolu
2021-01-10 3:41 ` Jakub Kicinski
2021-01-11 3:52 ` Sukadev Bhattiprolu
2021-01-11 19:43 ` Jakub Kicinski [this message]
2021-01-11 20:15 ` Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 6/7] ibmvnic: check adapter->state under state_lock Sukadev Bhattiprolu
2021-01-08 7:12 ` [PATCH 7/7] ibmvnic: add comments about adapter->state_lock Sukadev Bhattiprolu
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