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From: Christoph Hellwig <hch@lst.de>
To: Damien Le Moal <Damien.LeMoal@wdc.com>
Cc: Bart Van Assche <bvanassche@acm.org>,
	Keith Busch <kbusch@kernel.org>, Sagi Grimberg <sagi@grimberg.me>,
	Christoph Hellwig <hch@lst.de>,
	"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>
Subject: Re: [PATCH v3] nvme: Fix handling of large MDTS values
Date: Fri, 2 Apr 2021 08:35:40 +0200	[thread overview]
Message-ID: <20210402063540.GA5570@lst.de> (raw)
In-Reply-To: <BL0PR04MB6514CD8EA0289C5C52A1C47AE77A9@BL0PR04MB6514.namprd04.prod.outlook.com>

On Fri, Apr 02, 2021 at 05:00:58AM +0000, Damien Le Moal wrote:
> On 2021/04/02 10:47, Bart Van Assche wrote:
> > Instead of triggering an integer overflow and undefined behavior if MDTS is
> > large, set max_hw_sectors to UINT_MAX.
> > 
> > Cc: Christoph Hellwig <hch@lst.de>
> > Cc: Sagi Grimberg <sagi@grimberg.me>
> > Cc: Keith Busch <kbusch@kernel.org>
> > Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> > ---
> > 
> > Changes compared to v2: reduced the two max_hw_sectors = UINT_MAX statements into a single assignment.
> > Changes compared to v1: removed a dev_err() call.
> > 
> >  drivers/nvme/host/core.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> > index 40215a0246e4..87d43309742b 100644
> > --- a/drivers/nvme/host/core.c
> > +++ b/drivers/nvme/host/core.c
> > @@ -3123,10 +3123,10 @@ static int nvme_init_identify(struct nvme_ctrl *ctrl)
> >  
> >  	atomic_set(&ctrl->abort_limit, id->acl + 1);
> >  	ctrl->vwc = id->vwc;
> > -	if (id->mdts)
> > -		max_hw_sectors = 1 << (id->mdts + page_shift - 9);
> > -	else
> > +	if (!id->mdts || check_shl_overflow(1U, id->mdts + page_shift - 9,
> > +					    &max_hw_sectors)) {
> >  		max_hw_sectors = UINT_MAX;
> > +	}
> 
> Nit: this could be rewritten as:
> 
> 	if (!id->mdts ||
> 	    check_shl_overflow(1U, id->mdts + page_shift - 9, &max_hw_sectors))
> 		max_hw_sectors = UINT_MAX;
> 
> More readable and no unneeded brackets. No ?

I'll just fix this up when applying the patch.

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  reply	other threads:[~2021-04-02  6:36 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-02  1:39 [PATCH v3] nvme: Fix handling of large MDTS values Bart Van Assche
2021-04-02  1:49 ` Keith Busch
2021-04-02  5:00 ` Damien Le Moal
2021-04-02  6:35   ` Christoph Hellwig [this message]
2021-04-02 16:50 ` Christoph Hellwig

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