RE: [PATCH] hv: hv_fcopy: drop the obsolete message on transfer failure

[Dexuan Cui]

> -----Original Message-----
> From: Greg KH [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
> Sent: Thursday, November 27, 2014 7:54 AM
> To: Dexuan Cui
> Cc: linux-kernel@xxxxxxxxxxxxxxx; driverdev-devel@xxxxxxxxxxxxxxxxxxxxxx;
> olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; jasowang@xxxxxxxxxx; KY Srinivasan;
> Haiyang Zhang; vkuznets@xxxxxxxxxx
> Subject: Re: [PATCH] hv: hv_fcopy: drop the obsolete message on transfer
> failure
> 
> On Tue, Nov 11, 2014 at 09:03:26PM -0800, Dexuan Cui wrote:
> > In the case the user-space daemon crashes, hangs or is killed, we
> > need to down the semaphore, otherwise, after the daemon starts next
> > time, the obsolete data in fcopy_transaction.message or
> > fcopy_transaction.fcopy_msg will be used immediately.
> >
> > Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> > Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
> > ---
> >  drivers/hv/hv_fcopy.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/drivers/hv/hv_fcopy.c b/drivers/hv/hv_fcopy.c
> > index 23b2ce2..177122a 100644
> > --- a/drivers/hv/hv_fcopy.c
> > +++ b/drivers/hv/hv_fcopy.c
> > @@ -86,6 +86,15 @@ static void fcopy_work_func(struct work_struct
> *dummy)
> >  	 * process the pending transaction.
> >  	 */
> >  	fcopy_respond_to_host(HV_E_FAIL);
> > +
> > +	/* In the case the user-space daemon crashes, hangs or is killed, we
> > +	 * need to down the semaphore, otherwise, after the daemon starts
> next
> > +	 * time, the obsolete data in fcopy_transaction.message or
> > +	 * fcopy_transaction.fcopy_msg will be used immediately.
> > +	 */
> > +	if (down_trylock(&fcopy_transaction.read_sema))
> > +		pr_debug("FCP: failed to acquire the semaphore\n");
> 
> Why is "FCP:" needed?  pr_debug() should never need any type of prefix.
> 
> Please fix.
> 
> thanks,
> 
> greg k-h

Ok, I'll send a v2 soon.

Thanks,
-- Dexuan
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