Re: [PATCH] scsi: core: Fix missing lock when read async_scan in Scsi_Host

[Chaohai Chen]

On Tue, Mar 03, 2026 at 05:45:13PM +0900, Damien Le Moal wrote:
> On 3/2/26 21:13, Chaohai Chen wrote:
> > When setting the async_scan flag in host, the host lock was locked,
> > but it is not locked during reading. Encapsulate the corresponding
> > API to fix this issue.
> > 
> > Signed-off-by: Chaohai Chen <wdhh6@xxxxxxxxxx>
> > ---
> >  drivers/scsi/scsi_scan.c | 60 +++++++++++++++++++++++++++++-----------
> >  1 file changed, 44 insertions(+), 16 deletions(-)
> > 
> > diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
> > index 60c06fa4ec32..8b63130ef2e5 100644
> > --- a/drivers/scsi/scsi_scan.c
> > +++ b/drivers/scsi/scsi_scan.c
> > @@ -122,6 +122,42 @@ struct async_scan_data {
> >  	struct completion prev_finished;
> >  };
> >  
> > +static bool scsi_test_async_scan(struct Scsi_Host *shost)
> > +{
> > +	bool async;
> > +	unsigned long flags;
> > +
> > +	lockdep_assert_not_held(shost->host_lock);
> > +
> > +	spin_lock_irqsave(shost->host_lock, flags);
> > +	async = shost->async_scan;
> > +	spin_unlock_irqrestore(shost->host_lock, flags);
> > +
> > +	return async;
> > +}
> 
> Use an atomic ?
> 
The structure member async_stcan is defined in a bit field manner, 
and using atomic may change the structure definition, making it too complex