From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Sagi Grimberg <sagi@grimberg.me>,
chaitanya.kulkarni@wdc.com, kernel-janitors@vger.kernel.org,
james.smart@broadcom.com, linux-nvme@lists.infradead.org,
linux-kernel@vger.kernel.org,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
hch@lst.de
Subject: Re: [PATCH] nvmet-fc: Fix a missed _irqsave version of spin_lock in 'nvmet_fc_fod_op_done()'
Date: Tue, 25 Aug 2020 09:09:40 +0200 [thread overview]
Message-ID: <20200825070940.GD29268@lst.de> (raw)
In-Reply-To: <20200824211630.GA1490518@dhcp-10-100-145-180.wdl.wdc.com>
On Mon, Aug 24, 2020 at 02:16:30PM -0700, Keith Busch wrote:
> On Mon, Aug 24, 2020 at 01:00:11PM -0700, Sagi Grimberg wrote:
> > > The way 'spin_lock()' and 'spin_lock_irqsave()' are used is not consistent
> > > in this function.
> > >
> > > Use 'spin_lock_irqsave()' also here, as there is no guarantee that
> > > interruptions are disabled at that point, according to surrounding code.
> > >
> > > Fixes: a97ec51b37ef ("nvmet_fc: Rework target side abort handling")
> > > Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> > > ---
> > > Not tested, only based on what looks logical to me according to
> > > surrounding code
> > > ---
> > > drivers/nvme/target/fc.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
> > > index 55bafd56166a..e6861cc10e7d 100644
> > > --- a/drivers/nvme/target/fc.c
> > > +++ b/drivers/nvme/target/fc.c
> > > @@ -2342,9 +2342,9 @@ nvmet_fc_fod_op_done(struct nvmet_fc_fcp_iod *fod)
> > > return;
> > > if (fcpreq->fcp_error ||
> > > fcpreq->transferred_length != fcpreq->transfer_length) {
> > > - spin_lock(&fod->flock);
> > > + spin_lock_irqsave(&fod->flock, flags);
> > > fod->abort = true;
> > > - spin_unlock(&fod->flock);
> > > + spin_unlock_irqrestore(&fod->flock, flags);
> > > nvmet_req_complete(&fod->req, NVME_SC_INTERNAL);
> > > return;
> > >
> >
> > James, can I get a reviewed-by from you on this?
>
> afaics, the lock just serializes single writes, in which
> WRITE/READ_ONCE() can handle that without a lock, right?
It synchronizes a few fields, sometimes taken over multiple updates.
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next prev parent reply other threads:[~2020-08-25 7:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-21 7:58 [PATCH] nvmet-fc: Fix a missed _irqsave version of spin_lock in 'nvmet_fc_fod_op_done()' Christophe JAILLET
2020-08-24 20:00 ` Sagi Grimberg
2020-08-24 21:16 ` Keith Busch
2020-08-25 7:09 ` Christoph Hellwig [this message]
2020-08-25 7:10 ` Christoph Hellwig
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